Salt Mixes

All salt mixes are not alike.· They vary in quality of starting materials, percentages of components and additional additive quantities not normally found in sea water.

Starting Materials

The major component of salt mixes is sodium chloride or better known as table salt. It is mined in enormous quantities and purified in different ways. For aquarium salt, they use a “technical grade”.· An old joke was “Technically its salt” and it is 99+% pure. The other percent is comprised of other minerals and things like dust and clay. When you mix up a batch for your tank you often find sediment in the bottom of the mixing tank if you turn off the pump. This is harmless like dust on the furniture· There are other chemical grades listed below FYI. Considering the composition of natural seawater, technical grade is good enough and it is cost effective.· If a salt manufacture says they use more pure chemicals than the others, it’s only a fraction of a percent more pure and has no effect on the final product·except increasing the price. Other components are usually no more pure than lab grade·

Quality Control

This is one aspect few think about· There are specific percentages of each part of a saltwater mix. Let’s take iodide for example· Natural seawater has 0.06 % iodide content.· This amounts to 1.6 grams of sodium iodide added to a 1000 lbs of sodium chloride.· If you want to cut costs or you don’t care about consistency, a few tenths of a gram makes a significant difference and iodide is much more important than calcium.

Do you know what’s in your Salt Mix?

Let’s pretend you mix 109 pounds of sodium chloride (table salt), 5 pounds of calcium chloride (Turbo Calcium aka road deicer available at Home Depot in 50 lb. bags under $10)) and 25 pounds of magnesium sulfate (Epsom Salts) · This is about enough mix for 450 gallons· When you test the water, calcium will be 400+, pH will be 8.3, and magnesium will be really high. Everything you testing maniacs want will be there but it will be the worst mix you could get. My point is: TEST KITS can only tell you so much.

Things they don’t tell you

You don’t need dechlorinators when using salt mixes. You shouldn’t use tap water anyway and RO and/or DI water has already removed any chlorine. A very small amount of sodium thiosulfate is in the mix which destroys any chlorine but harmless otherwise. Second, salt water naturally reduces chlorine to chloride.

Fast dissolving Salt Mixes

This hobby is not for those who lack patience.· When mixing a new batch of saltwater, it should circulate for 24 hours.· During this time all the components are able to dissolve completely.· This also lets the pH and alkalinity stabilize.· Brands like Instant Ocean, Reef Crystals, and Oceanic (and others, I have been informed) use an additive called EDTA (EthyleneDiamineTetraacetic Acid). ·To keep it simple, things dissolve faster with it. It is also a cumulative poison that is absorbed by corals.· Eventually they are unable to take up food. We sell Crystal Sea that does not include EDTA which leads us to the next problem·

Coral Bleaching

Common reasons for coral bleaching include:

Not mixing salt long enough — 24 hours is necessary for stability. Less mixing may leave solids

Changing salt mixes too quickly — water changes should be 5 to 10% initially· If your water has lower than normal pH and it jumps quickly it hurts corals.

Large water changes — remove organics from the water that act as light filters.· The intensity of light increases noticeable with a large water change.

Critical Parameters

From most to least critical
Ammonia greater than minimum on most test kits
Nitrites greater than zero
pH under 8.2 or above 8.6 (average reading between morning and night)
Nitrates greater than 40 ppm (less critical in FISH ONLY tanks)
Temperature sustained under 70 or sustained above 80. See page on No Heaters .
Salinity too high (1.026 or greater)
Alkalinity lower than 240 ppm (4.8 Meq/L)
Light is too Iow or too high (coral/reef tanks only)
Salinity is too Iow (less than 1.020 for reefs, less than 1.015 sustained for fish)
Voltage in your tank above 2 volts AC (induced, shorts in equipment, not having a grounding wire).


Crystal Sea Marine Mix

At Seahorse we offer the best products at the best prices. After reading a research paper by Dr. Ronald Shimek, I chose to use and sell Crystal Sea Marine Mix because it fulfilled both criteria.  It’s made in Maryland and each batch is assayed by an independent laboratory and available upon request.  It is the only salt mix I’ve found that maintained a consistent pH and alkalinity up to 2 months without adding additional supplements. Since 1988, the U.S. EPA has referenced Crystal Sea as a replacement for natural seawater for bioassay testing.

Chemical Grades - from Highest Purity to Lowest
Highest quality; often equals or exceeds the latest purity standards set by the American Chemical Society (ACS). This is the only universally accepted standard. Chemicals are of the highest purity attainable.
Purity is generally equal to ACS grade. This grade is suitable for analytical work and is more than adequate for general lab use.
A grade of sufficient purity to pass certain tests prescribed by the US Pharmacopoeia (USP); acceptable for drug use. USP grade may be used for most laboratory purposes.
A grade of sufficient purity to meet the standards of the National Formulary (NF).
An upper-level intermediate quality, Exact impurities may not be known; however, lab grade is usually pure enough for most educational laboratories.
Purified, pure, or practical grade; a lower-level intermediate quality, Although this grade does contain impurities, it is usually pure enough for use in educational laboratories.

A good-quality grade used industrially, Use caution when substituting for reagent-grade or lab-grade chemicals.


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