Switching from BRS to ESV B ionic. What should I expect to change?

Randy Holmes-Farley · Mar 24, 2019

Yes, I meant I’d answered you a few minutes earlier. [emoji23]

soeminpaing · Jul 25, 2020

JimWelsh said:
My attempt at a Recipe for a True Two Part DIY Calcium and Alkalinity Supplement

In Randy's "Improved Do-it-Yourself Two-Part" Recipe #1, the two "parts" are Part 1, calcium chloride, and Part 2, sodium carbonate, in balanced proportions. After the calcium from Part 1 and the carbonate from Part 2 combine to create calcium carbonate, which is consumed by corals, coralline algae, or precipitation on heaters, etc., what remains is the sodium chloride. After using one gallon of each part, there will be about 413 grams of sodium chloride left over.

The Magnesium Portion Part 3A of Randy's recipe is designed to provide the correct amounts of magnesium, chloride, and sulfate to restore the ionic balance, so that the residual left over from the combined dosing of all three parts (after accounting for the magnesium that is integrated into coral skeletons) more closely resembles natural sea water rather than just a sodium chloride brine. Part 3A consists of a mixture of magnesium sulfate and magnesium chloride in the proper ratio to achieve this goal.

The exercise here is to figure out how we can accomplish the same thing, but using only two parts. The problem is that if we were to add magnesium sulfate to the calcium chloride solution (Part 1), then insoluble calcium sulfate will precipitate out. Similarly, if either magnesium compound were to be added to the sodium carbonate solution (Part 2), then insoluble magnesium carbonate and/or magnesium hydroxide will form. So, we need to use a combination of magnesium chloride, which will be added to Part 1, and sodium sulfate, which will be added to Part 2. Neither of these will cause any precipitation.

Keeping Randy's Recipe #1 at its original concentration, then to each gallon of Part 1 we will need to add 9 + 19.5 = 28.5 grams of magnesium (see Randy's article for the math behind these numbers). Since the atomic mass of magnesium is 24.305, we need 28.5 / 24.305 = 1.173 moles of magnesium chloride, which is about 238g of magnesium chloride hexahydrate, giving us the same about of magnesium as is in 610 ml of Randy's Part 3A. Since Part 3A has 70,000 ppm sulfate, then 610 ml of it contains 70,000 * 0.610 = about 42.7 g of sulfate, which is the amount found in about 63.14 g of sodium sulfate, which will need to be added to Part 2. These calculations are based on needing to provide the proper balance for that 413 grams of leftover sodium chloride after we use up one gallon of both Part 1 and Part 2.

Notice that all of the required magnesium is being added in the form of magnesium chloride, instead of a mixture of magnesium chloride and magnesium sulfate. That implies that we are adding more chloride than is necessary, since Randy's Part 3A strikes a proper balance between the relative amounts of magnesium, chloride, and sulfate needed. Notice also that all of the sulfate is being added in the form of sodium sulfate, meaning that we're also adding more sodium than is necessary. That extra sodium and the extra chloride means that we have added still more sodium chloride, and have thrown our mixtures out of balance once again, so now we have roughly 52 more grams of sodium chloride that needs balancing. Now we must calculate how much more magnesium chloride and sodium sulfate is needed to balance out that 52 more grams of sodium chloride, and then that will leave us once again with a bit more (about 6.25 g) leftover sodium chloride, and so on. After a few iterations of these calculations, though, the amounts we are talking about are so small that they really don't matter any more.

So, a True Two Part DIY can be created using the following recipe:

Part 1 - The Calcium and Magnesium Part
Dissolve 500 g of calcium chloride dihydrate plus 261.2 g of magnesium chloride hexahydrate in enough water to make a total volume of one gallon.

Part 2 - The Alkalinity and Sulfate Part
Dissolve 374.7 g of sodium carbonate (594 g of baking soda that has been baked) plus 68.7 g of sodium sulfate in enough water to make a total volume of one gallon.

This recipe is the same strength as Randy's Recipe #1. To make these two parts with the same strength as B-Ionic, then multiply the amounts of the salts by 1.5.

Comments / corrections / questions are welcome!

If I need to dose potassium can I switch potassium sulphate with sodium sulphate or will it screw the ionic balance .