Large tank diy 2 part solution (Very long winded warning!)

[Herpervet]

So I have used Randy's diy 3 part solution and for my 300 gallon and 500 gallon plus systems the solution volumes become ridiculous and I was adding over a liter a day of each part at one point.

I ended up going with a calcium reactor on my 550 system.

Anyway for my 300 I wanted the simplicity of the 2 part solution without having to mix up the solution, i.e. dosing dry products into my sump.

Here is the way I figured it out and I would like to get some feedback to make sure I havn't missed anything or made any major math errors.

Step 1- dkh was adjusted to 12.5 with bicarb and calcium adjusted to 430 with calcium chloride.

20 days later dkh was 6.4. Using the reef chemistry calculator I determined that it would take about 1.25tsp of baking soda daily to keep up with this rate of consumption.

This is only my starting point and of course I may have to increase or decrease depending on the dynamics of coralline growth, stony corals etc.

So 1.25tsp of baking soda weighs 8.175grams on my triple beam.

Randy's recipe 1 part 1 calls for 594grams of baking soda baked to remove water and C02 per gallon of water. I am assuming that there isn't a huge weight difference as a result of water and CO2 loss.

EDIT: I don't believe it matters at all since I am using an un-baked baking soda and Randy's solution contains 594 grams of baking soda. i.e. it is weighed before baking not after.

So 8.175/594=.01376 of a gallon per day if your still with me.

The calcium solution calls for 500grams of cacl2 or 400 grams of anhydrous cacl2 (Peladow) which is what I have.


.01376 x 400= 5.506 grams.

This is a very convenient number as 1tsp of peladow weighs right at 5.5 grams on my scale.

So if my math is correct I can add 1.25tsp of baking soda and 1 tsp of peladow daily to my sump daily and these are roughly equivalent to equal volumes of randy's solutions but without mixing the solution.

Please point out if I have made any mistakes here.

The last step is to figure how much magnesium to add.

After each gallon of part 1 and 2 is added 610 ml of mg solution is added.

One gallon of the calcium part contains roughly 72.75 tsp of peladow (400grams/5.5grams per tsp=72.72 tsp)

One gallon of the alk solution contains 90.68tsp of baking soda
594grams/6.55grams per tsp=90.68tsp

So after roughly 73 tsp of peladow and 91tsp baking soda is added 610ml of the magnesium stock solution is needed.

1 gallon= 3785ml

610/3785= .16116 of a gallon per dose.

The magnesium solution is made with 3 cups epsom salts and 5 cups mag chloride.

1 cup =48tsp

.16116x3x48=23.2tsp epsom salts


.16116x5x48=38.67tsp mg chloride.


So every 73 days I will use the equivalent of 1 gallon of part1 and 2 (calcium and alkalinity parts) and need to add 23 tsp epsom salts and 39tsp mg chloride.

I would rather dose more frequently to keep the magnesium up so I figured out a weekly dose.

If you divide this out to once a week it comes to roughly 2.25tsp epsom salts and 3.75tsp mg chloride every 7 days.


So to recap: For my large system I am adding 1.25tsp baking soda and 1tsp anhydrous cacl2 daily.

2.25tsp epsom salts and 3.75tsp mg chloride every 7 days.

Please correct any significant errors in math or reasoning.

If the math is indeed correct then you can scale this up or down for any relatively large system and still be essentially as balanced as Randy's solutions I would think.

[Mike O'Brien]

That's basically what I do. My ATO is a constant drip, so I put a cup under that that I add the baking soda to. That gives it a slow dose to the tank. I mix the calcium with RO water before adding, and only occasionally add Mg as needed. I'm not sure what the difference would be adding the chemicals dry, but it only takes a minute or two to dissolve the Calcium.