What Is It?

Aluminum, Cadmium, Chromium, Lead, Mercury, Nickel, and Zinc

Any of these elements at slightly elevated levels are undesirable in an aquatic system. Traces are commonly found in many municipal water supplies, chemical additives, and various water treatment chemicals. However, in an aquatic system they can slowly accumulate to toxic levels. If your water supply contains slightly elevated levels, even reverse osmosis can only remove a percentage of them. Therefore, you could be introducing these toxic elements into your delicate life support system.

If test results indicate high levels of any of these elements, the source must be identified and eliminated to prevent further addition of these very undesirable components.

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Boron levels are important for the buffering capacity or carbonate hardness of a marine system. Some synthetic salts contain elevated levels and many aquarists use excessive amounts of buffers to control pH. This creates an imbalance in the water chemistry and provides a less than optimum environment for the lifeforms. We suggest a natural approach to pH control without "stressing" the chemistry.

If test results indicate elevated levels of Boron, stop using buffers and hardness builders and monitor pH closely. Usually pH will maintain desirable levels in a chemically balanced system. If pH continues to drop, perhaps some other source of acidification exists. Food, additives, and decomposition by-products are often the cause. If these cannot be eliminated, we recommend judicious use of high purity sodium hydroxide. Small amounts of this will raise the pH and by diluting in water before addition, one can also increase the buffering capacity. Consult our lab for more details.


Most Aquarists realize the importance of Calcium in a marine system and often measure its concentration with kits that usually don't provide accurate results. The Hach kit for example cannot measure calcium in seawater accurately. It suffers from interferences from other alkali earths (Magnesium, Strontium, and Barium) and others. Try using several different kits for Calcium and you will probably get several different values. If you truly need to boost Calcium levels, we offer a custom-made Calcium salt which is added to your kalkwasser and naturally supplements your system with this important element.


Copper in a fish-only system may safely run as high as 300 ppb, but a reef system should contain from less than 1 to 5 or 10 ppb Copper! Most test kits cannot measure at these levels and if they do, their accuracy is dubious. Our Copper test truly measures total Copper, including that which may be chelated with citrate, EDTA, or other unnatural sequestering agents. Most kits provide free Copper concentrations only. This is a misleading measurement.


Iron is an element that is often overdosed in a closed system. Elevated levels can cause undesirable algal blooms and create an imbalanced micronutrient profile. Natural reef waters contain low ppb levels of this element as hydroxy complexes. Most kits that measure Iron suffer from interferences with Copper and Cobalt. Additionally, they usually measure only one form of Iron and don't react with complexed (naturally occurring) forms. Our method measures total Iron, in any form or complex that it may exist in.


Iodine is probably the most controversial element in closed marine systems. It is very difficult to accurately measure and exists in several forms in seawater. Its stability is still not fully understood, especially in closed systems with powerful filtration. The few kits that do exist suffer from a plethora of interferences and only measure elemental iodine. The Iodine in natural seawater exists as both Iodide and Iodate, not elemental Iodine. Most Aquarists supplement closed systems with this element, however both correct forms should be added judiciously. ENC Labs provides a custom-made, stable supplement of Iodine in the dry form that is tailored to your system capacity. It delivers the same types and amounts of Iodine present in natural seawater to your system.


Some synthetic salts contain significantly elevated levels of Lithium probably from the impurities found in the chemicals which they are made from. This certainly provides an environment different from that of natural ocean/reef water. The effects of these levels have not been fully investigated, however current research indicates obvious biological effects {Proc. Natl. Acad. Sci., 86, 3669-3673} and {Develop. Growth & Diff., 33(4), 411-419 (1991)}. Some additives also contain traces of this element which contribute to the high levels of lithium found in some marine systems. Does your salt suffer from this potential problem? If test results indicate high levels of this element, we simply recommend changing salts and stop using additives that may contain these impurities. If this is not practical, specific media to reduce levels of this element can be employed {Colloids and Surfaces, 47 (1990) 69-79}.


Molybdenum is another element which many Aquarists recognize the importance of. However, in closed systems it is often at levels that are not optimum like those found in natural ocean/reef water. Natural reef water contains about 5 to 15 ppb of this trace element which participates in biochemical re-dox reactions such as nitrogen fixation among other things. Many Aquarists add mixtures of trace elements which provide uncertain amounts of this important element. Some salts are notorious for having reduced levels of Molybdenum. If test results indicate a deficiency of this component ENC Labs provides a custom-made, stable form in the dry state that is tailored to your system capacity. Additionally, it delivers the correct amount and form of Molybdenum found in natural seawater (Mo+6).


Most Aquarists recognize the importance of Strontium in marine systems, especially those with hard corals and more delicate species. However, it is often added improperly and not measured accurately with the few kits that do exist. If needed, ENC Labs offers a purified, caustic form of this element that is added to your kalkwasser and delivered in a more effective way than other supplements on the market. It is also custom-made to the capacity of your system. Additionally, it boosts the alkalinity of your kalkwasser by virtue of its elevated pH.

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Phosphorus and Phosphates are often discussed but almost always incorrectly measured. A necessary nutrient in all marine systems, but elevated levels cause excess algal growth and create an unhealthy environment for the lifeforms. Most kits measure ortho-phosphate, which is only one form of Phosphorus. Many other forms exist which are not measured and will cause similar problems in a marine system. Our method firsts digests all forms of this element and measures the liberated Phosphorus for a total-Phosphorus determination.

Water supplies often contain elevated levels of various forms of this element and RO/DI systems must therefore be properly maintained to control levels of this nutrient. Additionally, many foods and some additives contain excess amounts of this element. Even seafood purchased for human consumption contain levels of Phosphorus that are unacceptable in delicate marine systems. If you have any type of excess algal growth, you may have too much of this component in your system. If test results indicate elevated levels, ENC Labs must identify the source of this nutrient and prevent further addition to your system.

Total Organic Carbon (TOC)

This is an excellent measure of the bio-load on an aquatic system. It represents any carbon derived from organic matter (other than inorganic sources such as carbonates). In natural seawater, the primary input of this component is from the photosynthetic fixation of inorganic carbon dioxide by phytoplankton. In a closed system, the TOC could be coming from any photosynthetic organism which also fixes carbon, waste from various life forms, or other artificial sources such as vitamins, supplements, and additives that are dosed into the system. Ultimately, these organic components become nutrients, but excessive levels are unhealthy.

Natural seawater contains about 1 ppm TOC and is considered to be "nutrient-poor." Closed marine systems often contain elevated levels such as 10 to 25 ppm TOC. This is undesirable, especially in a reef environment. If test results indicate this condition, we advise judicious use of a high quality activated carbon strategically placed in the water flow. Ozone can also be used to control this parameter in closed systems. If elevated levels persist, we must identify the source of this nutrient and limit its addition to the system creating a more desirable environment for the lifeforms.

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To obtain sample containers or request additional information contact us at inquiry@enclabs.com