Thioguard® is Superior to Lime Slurry and Caustic Soda



On the surface, it’s easy to do the theoretical calculations and provide exact alkaline equivalents. However, field and trial experience tells us something different. The amount of high grade Thioguard® – magnesium hydroxide required to achieve equivalent buffering/performance benefits in the biological reactors tends to be much lower than the calculations would suggest. Why?

Often overlooked are some of the side impacts of lime use, such as softening and pH spikes, and confusion about what standard total alkalinity tests are telling us. An easy way to find out the extent of softening that is taking place in your facility, is to filter your sample with a 0.45 micron filter before titration. This will remove the insoluble CaCO3 particles that are not “biologically available.” Another significant, yet overlooked impact is the EPA documented sludge production typically associated with lime.

EPA – wastewater technology fact sheet – chemical precipitation: “the addition of treatment chemicals, especially lime, may increase volume of waste sludge up to 50%.”


Lime is commonly used in potable water to “soften,” or remove hardness minerals, such as calcium and magnesium from drinking water, in an effort to minimize the effects of potential scaling in the water distribution system. However, in the softening process, calcium and magnesium are removed from water in the form of calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) which are also forms of alkalinity. Removing hardness from water also removes alkalinity.

Lime SofteningIn wastewater, lime is often considered as an alkalinity supplement. However, the effects of lime softening can have undesirable consequences to the biological system, e.g., removal of alkalinity, creation of CaCO3 sludge, and the potential for bio-upsetting pH spikes.

Hot Zones Temperate ZonesThe simple fact: Thioguard® and lime slurry have different physical and chemical properties that affect how each responds to and reacts with the systems to which they are added. And because of these differences in properties, the impacts they impart and the utility for their use are starkly different.


  • Because of the high solubility of both caustic soda and lime, pH often becomes
    biologically prohibitive before ideal alkalinity levels and process stability can
    be reached.
  • The use of lime in, or prior to, primary treatment can actually reduce alkalinity going into the secondary treatment processes by precipitating CaCO3 in the primary clarifiers
  • Lime produces calcium carbonate in wastewater which acts as a coagulant for hardness and particulate matter.
  • Lime is an effective phosphate removal agent, but results in a large sludge volume and the addition of treatment chemicals, especially lime, may increase the volume of waste sludge up to 50 percent.

Hydrated Lime added in collection systems increases O&M costs
related to formation of scale and accumulated solids/sludge.
In severe cases this leads to line blockages and SSO’s

The use of lime generates significant amounts of sludge in wastewater collection systems and treatment plants. On a chemical basis, one ton of lime can generate as much as 5 tons of 20% sludge cake to remove or dispose. In contrast, Thioguard® reactions in wastewater produce only water and water-soluble products as TDS with NO added sludge. In fact, customers using Thioguard® have reported reductions of 15%-25% in total solids/sludge produced, due to a combination of improved biological performance, divalent cation bridging of floc matrix, and reduced inorganic solids loading.

Most wastewater treatment plant operators understand that their wastewater treatment plants function best at some ideal pH and that a minimum amount of alkalinity is required to keep microorganisms happy. But too often, the values of pH and alkalinity are incorrectly used interchangeably, and a thorough understanding of each parameter’s true relationship to biological stability and optimal performance – gets lost in the translation.

Most often this error in terminology stems from the use of the most common alkaline pH modifiers and alkalinity supplements, caustic soda and lime, where their use may successfully meet pH demands, but will likely fall short in supplying adequate alkalinity requirements without adversely elevating pH beyond biologically healthy limits. And often, maintaining pH stability and uniformity across entire treatment basins remains a virtual impossibility.

Compared to caustic soda or lime, Thioguard® is capable of supplying significantly more alkalinity in a bio-available form to a microbial wastewater system without adversely affecting pH. This creates a more suitable environment for bioremediation of BOD and nutrients like nitrogen and phosphorus. Moreover, because magnesium supplies a light-weight, divalent cation, unlike the monovalent sodium in caustic, and heavier calcium in lime, Thioguard® helps to generate a denser, more easily dewatered sludge, with a higher percentage of cake solids.

Lb.s Alkalinity Per Gallon


  • It takes 100+ mg/L of Thioguard® to raise a water sample to pH 8.8.
  • This same 100 mg/L of Thioguard® has the same neutralizing power as 138 mg/L of caustic soda and 135 mg/L of lime and would be the equivalent of, though significantly more reactive than, adding 172 mg/ L calcium carbonate alkalinity on a CaCO3 basis, assuming 100% bicarbonate conversion.

Thioguard Reactor systems treated to an initial pH of 8.5 using Thioguard, caustic soda and lime.Equivalent amounts of acid added to each over time.


THIOGUARD® Outperforms Nitrates from Collection System to Effluent

Calcium Nitrate products are commonly used in many of the nation’s wastewater collection systems, and they do essentially one thing – they treat odors from H2S. Unfortunately, there are multiple costly and problematic unintended consequences of the use of nitrate products. In addition, while nitrate use may temporarily address H2S odor problems, nitrate products are of little or no use in combating corrosion, which is a tremendous problem both in-plant and throughout every segment of wastewater treatment infrastructure.

where you don’t want them to occur.
Think denitrification…which consumes organics, and produces nitrogen gas N2 and carbon dioxide CO2, all seemingly innocuous by-products of Calcium Nitrate’s intended use as an odor control technology…but let’s take a closer look…

1. Nitrates contribute to the formation of F.O.G.
The addition of nitrates contributes to the accumulation of an odorous film, often referred to as a F.O.G. (Fats, Oils and Grease) mat in pumping stations and at your plant. Blockages associated with F.O.G. have been shown to be the greatest contributors to O&M costs including energy consumption, maintenance costs, and Sanitary Sewer Overflows (SSOs).

2. Nitrates contribute to Gas Binding in the Collection System
The transfer of wastewater can result in the release of gases such as O2 – Oxygen, CO2 – Carbon Dioxide, N2 – Nitrogen Gas, H2S – Hydrogen Sulfide, CH4 – Methane, VOCs – Volatile Organic Compounds, and VOSCs – Volatile Organic Sulfur Compounds, among others. Some of these gases are drawn into the system through pumping and ventilation, while others are generated within the system either chemically or biologically. These gases can result in the development of gas binding in the system, and are dramatically exacerbated with the utilization of calcium nitrate.


3. Nitrates upset the Bio-P process at your plant
The use of nitrates in the collection system alter the chemical and biological conditions of the collection system, which would otherwise facilitate the formation and transport of VFAs to the treatment plant, where they can be used by PAOs in Bio-P processes.

As VFAs (Volatile Fatty Acids) are eliminated with calcium nitrate addition, VFAs are therefore not available for PAOs (phosphorus accumulating organisms) for phosphate removal at the wastewater treatment plant.

4. Nitrates negatively impact Primary and Secondary Clarification
The addition of nitrates is not an exact science, and unfortunately, every step along the way there are costly unintended consequences. Add too little, and you’re facing odor problems. Add too much, and you’re faced with the formation of unwanted bubble-forming gases (N2 and CO2 from denitrification) in your settling tank, exactly where you DON’T WANT IT, continuing the formation of F.O.G. mat, (as well as creating an environment unfavorable to your biological processes). This often results in increased metal salts usage or increased polymer usage and associated increases in costs.

Calcium Nitrate has a short half-life in sewers, and therefore many addition locations are required to achieve adequate system-wide control. This requires several addition locations, and corresponding higher costs and operational oversight. In contrast, a single THIOGUARD Feed Unit can often replace several nitrate feed stations, and maintain a relatively constant pH level throughout.

Maintaining a constant surface pH of 6-8 can reduce the rate of corrosion by as much as 100X. The cost of simply ignoring this problem is monumental and THIOGUARD is the only commonly used product that has a direct mechanism to increase surface pH and prevent corrosion.


  • Decrease maintenance costs
  • Decrease operating power costs
  • Decrease F.O.G. related SSOs and ARV malfunction
  • Improve efficiency due to reduced discharge pressure in manifolded force mains
  • Improve Biosolids
  • Save money and improve plant performance ACROSS THE BOARD!

Nurturing the Brain with Magnesium

Magnesium is everywhere – it does not occur free in nature, only in combination with other elements, but it is the eighth most abundant chemical element in the Earth’s crust and the third most abundant element in seawater; it is even the ninth most abundant in the Milky Way. In the human body, magnesium is the fourth most abundant ion and the eleventh most abundant element by mass, being stored in bones, muscles, and soft tissues.

Magnesium is fundamental for health: it is essential to all cells and to the function of hundreds of enzymes, including enzymes that synthesize DNA and RNA, and enzymes involved in cellular energy metabolism, many of which are vital. Magnesium is involved in virtually every major metabolic and biochemical process in our cells and it plays a critical role in the physiology of basically every single organ.

Low plasma levels of magnesium are common and are mostly due to poor dietary intake, which has lowered significantly in the last decades. Magnesium can be found in high quantities in foods containing dietary fiber, including green leafy vegetables, legumes, nuts, seeds, and whole grains. But although magnesium is widely distributed in vegetable and animal foods, some types of food processing can lower magnesium content up to 90%. Also, the soil used for conventional agriculture is becoming increasingly deprived of essential minerals. In the last 60 years, the magnesium content in fruit and vegetables has decreased by around 20 to 30%.

Symptomatic magnesium deficiency due to low dietary intake in healthy people is not very frequent, but a consistently poor dietary supply of magnesium has insidious effects. Magnesium deficiency alters biochemical pathways and increases the risk of a wide range of diseases over time, namely hypertension and cardiovascular diseases, metabolic diseases, osteoporosis, and migraine headaches, for example.

In the brain, magnesium is an important regulator of neurotransmitter signaling, particularly glutamate and GABA, the main neurotransmitters by modulating the activation of NMDA glutamate receptors and GABAA receptors. It also contributes to the maintenance of adequate calcium levels in the cell through the regulation of calcium channels’ activity.

These physiological roles make magnesium an essential element in important neuronal processes. Magnesium participates in the mechanisms of synaptic transmission, neuronal plasticity, and consequently, learning and memory. Accordingly, increased levels of magnesium in the brain have been shown to promote multiple mechanisms of synaptic plasticity that enhance different forms of learning and memory, and delay age-related cognitive decline. Increased levels of magnesium in the brain have also been linked to an increased proliferation of neural stem cells, indicating that it may promote the generation of new neurons (neurogenesis) in adulthood. This is an important feature because neurogenesis is a key mechanism in the brain’s structural and functional adaptability, in cognitive flexibility, and in mood regulation.

Magnesium supplementation has also been shown to modulate the neuroendocrine system and to improve sleep quality by promoting slow wave (deep) sleep, which, among many other functions, is also important for cognition and memory consolidation.

Furthermore, magnesium may enhance the beneficial effects of exercise in the brain, since it has been shown to increase the availability of glucose in the blood, muscle, and brain, and diminish the accumulation of lactate in the blood and muscles during exercise.

But just as increasing magnesium levels can be beneficial, magnesium deficiency can have serious harmful effects.

Magnesium has important roles in the regulation of oxidative stress, inflammatory processes and modulation of brain blood flow. In circumstances of magnesium deficiency, all of these functions can potentially be dysregulated, laying ground for neurological disorders. Also, in a context of low magnesium availability in the brain, NMDA glutamate receptors, which are excitatory, may become excessively activated, and GABAA receptors, which are inhibitory, may become insufficiently activated; this can lead to neuronal hyperactivity and to a condition known as glutamate excitotoxicity. This causes an excessive accumulation of calcium in neurons, which in turn leads to the production of toxic reactive oxygen species and, ultimately, to neuronal cell death.

Magnesium deficiency has been associated with several neurological and psychiatric diseases, including migraine, epilepsy, depression, schizophrenia, bipolar disorder, stress, and neurodegenerative diseases. Magnesium supplementation has shown beneficial effects on many of these conditions, as well as in post-stroke, post-traumatic brain injury, and post-spinal cord injury therapies. This therapeutic action is likely due to its action in blocking NMDA glutamate receptors and decreasing excitotoxicity, in reducing oxidative stress and inflammation, and in increasing blood flow to the brain, all of which are determinant in the outcome of these conditions.

There are multiple benefits to be obtained from magnesium, both from a health promotion, and from a disease prevention and management perspective. The recommended daily intake of magnesium is of 320mg for females and 420mg for males. Too much magnesium from food sources has no associated health risks in healthy individuals because the kidneys readily eliminate the excess. However, there is a recommended upper intake level for supplemental magnesium, since it can cause gastrointestinal side effects. So, keep it below 350mg/day.


Magnesium, Hard Water, and Health

The risk relationship between hard water and reduced cardiovascular disease is well known, but it’s the magnesium portion of the hardness that accounts for most of the beneficial effect. Magnesium is important in hundreds of biochemical processes, and adult daily requirements are approximately 300-350 mg/day. Most Americans consume less than the optimal daily amount of magnesium recommended for good health. Although diet is the major source of magnesium, drinking water can be an important contributor, and the uptake of magnesium from drinking water is more efficient than from most dietary components except milk/dairy. Dairy intake tends to decline with age, so even a small (~10 mg/L) consistent lifetime contribution from water can be an important supplement as we age. Bottled waters and naturally soft and softened waters tend to have little or no magnesium.


Approximately half of the US population has been shown to consume less than the daily requirement of magnesium from foods (USDA & HHS 2015). The 2015 Dietary Guidelines Advisory Committee considered magnesium to be a shortfall nutrient that was under-consumed relative to the estimated average requirement (EAR) for many Americans. Magnesium deficiency and hypomagnesemia manifest in numerous disorders and diseases. Although diet is the primary source of intake, drinking water can be a lifetime contributor of supplemental magnesium to one’s total daily intake depending on the source water composition and the treatment it has received.


Daily Dose with Dr. Oz: Magnesium

Dr. Oz Investigates…

Magnesium has been in the spotlight lately and getting a lot of attention from health experts. This mineral plays a role in the physiological functions of the brain, heart, and muscles. Researchers continue to study how it can help your health by improving sleep, fighting depression, and reducing the risk of disease. You may want to consider adding a magnesium supplement to your daily routine and eating foods that are rich in magnesium, like leafy greens and pumpkin seeds. As always, make sure to speak to your doctor before making any major health changes. Want to learn more about the benefits? Check out six of the most significant reasons to give magnesium a try.

THIOGUARD® OMEGA-S: Nutrient Management

The chemical components of struvite (magnesium, ammonia, phosphorous) exist in every wastewater system. They are specifically found at more highly concentrated levels in biological processes, such as anaerobic digestion… yet struvite scale is not prolific at every plant. This is irrespective of their use of magnesium hydroxide. For several years, Premier has had many customers using THIOGUARD® experiencing no negative impacts from struvite.

Why? Magnesium, an ingredient in THIOGUARD®, is rarely the causative factor for struvite formation. The real explanation is the concentration ratio of the three components mentioned above, COUPLED with mechanical, hydraulic, or chemical inputs facilitating localized aqueous pH spikes, promoting high omega factors, and thus struvite formation (i.e. pump volute or mixer, turbulent elbow, excess caustic or soda ash addition).

THIOGUARD® ΩMEGA-S is an easy turnkey patent pending process. The THIOGUARD® ΩMEGA-S program is a small fraction of the cost of other aggressive methods. A few milligrams of Omega-S combined with THIOGUARD® treatment will insure that struvite will not form under any of the many circumstances that can cause the problem.

Preserving and Maintaining Assets with Thioguard


Sulfide gas is converted to corrosive sulfuric acid on infrastructure surfaces.

The acid dissolves concrete and metal on surfaces inside sewers and wastewater treatment plants, throughout the entire treatment and delivery process. Acidic Corrosion is prevalent in virtually every stage of the process – in your Collection System, your Headworks, in Primary and Secondary Clarifiers, in your Digesters, and in the Disinfection Processes. Corrosion is a system-wide problem, requiring a system-wide solution.


Adding or creating ALKALINITY is the most direct and effective way to neutralize the problem of excessive acidity in our water and wastewater infrastructure. However, many common treatments either provide no acid neutralization, or actually consume alkalinity in their chemistry.

Thioguard® provides the greatest power to neutralize acid over long infrastructure distances while providing additional benefits to your WWTP plant’s biological treatment processes. The chart above compares the alkalinity per gallon, among the most commonly used treatment options.


In an acidic environment (pH=2), corrosion is rampant, tearing through 2″ of concrete in as little as 8 years. When effective surface pH=4, similar corrosion levels are pushed out to 50+ years.


By reducing the acidity in your system, you’ll reduce corrosion dramatically, in some cases by as much as 100X, when compared to other treatments. Thioguard® is typically added through a single Feed Unit, and provides “corrosion-controlling” benefits throughout your system, from collection system source to treatment plant discharge.

The measured surface pH can then be used to correlate corrosion rate and subsequently, remaining years of useful life of a concrete structure.

The use of Thioguard® by direct addition has been demonstrated to elevate surface pH from a highly corrosive pH=0-2 up to a more desirable range of pH=5-9.


Thioguard® is the ONLY commonly used product that has a direct mechanism to PREVENT CORROSION. The benefits of adding Thioguard® to your treatment processes are not limited to the prevention or reduction of corrosion. You will also benefit from a reduction in the formation of sludge – significantly reducing your handling and transportation costs. The benefits are numerous and system-wide, making Thioguard® the Practical Choice for your system.


Thioguard: The Safe Alternative



One total system treatment (Thioguard® TST) replaces multiple chemical additives, saving money and hassle.

Technical grade magnesium hydroxide is environmentally safe, non-hazardous and safe to handle.

Thioguard® will provide a no-cost, no-obligation
expert system assessment.

Thioguard® provides positive plant benefits for nitrification, biosolids production & digester performance.

Technical grade magnesium hydroxide provides highest pounds of alkalinity per gallon, compared to any other additive. (See chart below. Click to view larger size.)

Enhance Phosphate Treatment with THIOGUARD®

In plants currently using metal salts, the addition of
THIOGUARD® technical grade magnesium hydroxide can

Increased regulation of total phosphorus limits are a fact of life, and another challenge for WWT plant operators and engineers. In most treatment plants, metal salts (ferrous/ferric or aluminum) are added for the treatment of phosphates.

Adding THIOGUARD® technical grade magnesium hydroxide will:

  • Minimize or eliminate the addition of metal salts
  • Enhance biological phosphorus uptake in bioreactors
  • Reduce the amount of metal-laden sludge
  • Increase agricultural phosphate recovery
  • Reduce dewatering, handling and transportation costs
  • Eliminate the need for expensive plant upgrades

THIOGUARD® is specifically formulated for maximum alkalinity
and magnesium utilization in biological processes, enhancing the
performance of metal salts in removing phosphates chemically –
while simultaneously improving biological uptake in bioreactors.



THIOGUARD® improves plant performance
Improved plant performance =
Significant Savings

Thioguard is engineered to provide maximum magnesium hydroxide and sustained alkaline utilization, enhancing the formation of metal hydroxide precipitate and increasing the adsorption of soluble phosphorus.



The benefits of adding THIOGUARD® to your treatment processes are not limited to enhanced phosphorus treatment and management. In addition, THIOGUARD® is the ONLY commonly used product that has a direct mechanism to prevent corrosion through sustainable and balanced pH levels. You will also benefit from a reduction in the formation of metal-laden sludge – significantly reducing your handling and transportation costs. The benefits are numerous and system-wide, making THIOGUARD® the practical choice for your entire system.

Thioguard-Mg: Enhancing Resource Recovery and Reuse Value – Biosolids, Energy, Nutrients


Chlorophyll is essential in photosynthesis, allowing plants to absorb energy from light.




Magnesium occupies the central position of the chlorophyll molecule, the green pigment which enables the plant to utilize solar energy for the production of organic matter (figure 1).

It is, therefore, not surprising that an adequate Mg supply to the plants may act as an activator of important enzymes in phosphorylation, the fundamental process of energy transfer in the plant. The involvement of Mg in the formation of protein is illustrated in Figure 4 which shows the protein content of young oat plants as influenced by Mg supply.


Although the parent materials of some soils may contain very high amounts of magnesium (e.g. basalt, peridotite and dolomite), the total Mg contents of most soils are rather low, namely between 0.05% and 0.5% Mg . Of this amount only a fraction is easily available to the plant, i.e. the magnesium present in the soil solution and the exchangeable Mg absorbed to clay minerals or soil organic matter. High levels of Mg are found in some saline and alkali soils and in soils with a high content of magnesium carbonate. But many of the agricultural soils are low in exchangeable magnesium, particularly those in the humid zones of temperate and tropical climates. High rainfall and soil acidity together with low cation exchange capacity increase the mobility of magnesium and cause heavy losses by leaching. Under these conditions the Mg status of the soils is poor.

In tropical Latin America, for instance, 731 million hectares are deficient in magnesium (or 49% all soils) mostly classified as Oxisols and Utisols (Ferralsols & Acisols according to the FAO-UNESCO soil map of the world).  In Brazil, Mg deficiency symptoms on annual crops have been recorded as frequently as potassium deficiency. In the humid tropics and the wooded savannah of Africa, the soils with low base status which are presently or potentially deficient in Mg cover 44% of the area. In tropical Asia, they amount to 59%. Mg deficient areas in the USA are shown in Figure 2.

Usually, soils are considered deficient in plant available magnesium when the content of exchangeable magnesium is below 3-4 mg/100 g of soil. The critical values differ according to the soil texture. They are higher in soils with high content of 2:1 layer clay minerals and high organic matter. An example of Mg soil test rating for the Federal Republic of Germany is given in Table 2.

As for other plant nutrients, the status of available magnesium in the soil cannot be considered independently. It is influenced by the contents of other cations, such as calcium (Ca) and potassium (K), and by the soil acidity (pH). The relationship between Mg deficiency of oats and the pH of sandy soils is illustrated in Figure 5.

The occurrence of Mg deficiency symptoms was lowest at about pH 5, indicating an optimum of Mg availability at this pH range. At lower pH, the uptake of Mg is reduced due to the increased concentration of hydrogen (H) and aluminum (al) ions. In very acid tropical soils, mainly formed by sesquioxides of aluminum and iron, the addition of magnesium fertilizers to the soil reduces Al toxicity. At high soil pH, the competition of Ca ions is responsible for the lower Mg uptake. Regardless of the PH, ammonium (NH4) and potassium (K) affect the uptake of magnesium. Thus, heavy dressings of ammonium sulphate or potassium chloride can aggravate Mg deficiency.


Plants take up magnesium in smaller quantities than potassium, although the contents of exchangeable Mg in the soil and the Mg concentration of the soil solution are often higher than the corresponding values for K. There is antagonism between K and Mg but it seems to be confined to the deficiency range of nutrient availability. Under such conditions, increasing the supply of one nutrient aggravates the deficiency of the other. Usually high contents of Mg can be found in plants deficient in K (plants try to keep the sum of the cations K, Ca, Mg, Na fairly constant). Application of potash fertilizers to correct K deficiency leads to a gradual decrease of magnesium contents in the plant. Provided that the soil is well supplied with available Mg, leaf magnesium will not fall off to dangerously low values but remains above the critical level even at the high K rates needed to exploit the genetic yield potential of the plant (Figure 6).

When both K and Mg are deficient, it is advisable to improve the magnesium status of the soil by adequate Mg fertilizer dressings before applying heavy doses of K.


Magnesium deficiency symptoms are more and more observed not only on Mg defined soils but also on soils originally well supplied with this nutrient. This is due to higher Mg uptake by high yielding crops under intensive cultivation.

If the requirements are not met by the magnesium supply of the soil or by the application of Mg-containing fertilizers, plants will suffer from Mg deficiency and may show deficiency symptoms at various growth stages.

As magnesium is rather mobile and can be easily transported to the actively growing plant parts, Mg deficiency generally first becomes visible on the older leaves. Although the symptoms differ between plant species, some general characteristics are apparent.

Mg deficiency becomes manifest by pale discoloration of the leaves in part or as a whole (chlorosis) while the veins remain green. At a later stage the color of the affected areas changes to yellowish white; they become translucent and then take a dark color and eventually die (necrosis). In most cases the leaves are brittle and premature defoliation is observed, especially in fruit trees.

For graminaceous crops, ratings of Mg deficiency symptoms have been established as given in Table 3.

Magnesium plays an essential role in the human and animal metabolism. It is a constituent of many enzymes, the key substances that regulate the life processes in the cells and organs of the body. Too low a Magnesium supply may lead to tetany (e.g. grass tetany, a lethal disease of dairy cattle), brain disturbances, muscular cramp, and eventually heart diseases.

Magnesium deficiency can be avoided if a food source contains sufficient Magnesium. The daily requirement is about 0.3-0.4g of Magnesium for an adult person. The magnesium needs of animals differ greatly. A dairy cow may require 3-6 g of magnesium per day, depending on the level of milk production. However, as the utilization of the magnesium contained in the forage is rather low (in young pasture grass only 10%), the actual quantity needed may become as high as 50 grams of magnesium per day or more. To assure an adequate supply of magnesium to dairy cattle, the forage should contain sufficient magnesium, at least 2 grams of magnesium per kg dry matter. The average Magnesium contents of some food and forage materials are given in Table 4.