Help me with mixing up liquid ferts

1171 Views 8 Replies 3 Participants Last post by Rush3737, Mar 4, 2014

Rush3737

Discussion Starter · Mar 3, 2014

Okay, so all the calculators I found online confuse me. Some do some good stuff, and others do other stuff well, but I really didn't find any that would do exactly what I wanted.

I have KNO3, KH2PO4, and K2SO4 for Macro, and CSM+B for micro.

I just ordered 32oz (946 mL) bottles.

How much of each do I add when I mix? And how much do I dose for a 75g tank. Even If someone could kind of just give some pointers on working my way through the calculators with this info that would also be great.

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Darkblade48

· #2 · Mar 3, 2014

There are lots of dosing regimens out there; which do you plan to use?

For example, classic EI, as outlined by Tom Barr (for the aquarium you have) would be as follows:

60 – 80 Gallon Aquariums
+/- 3/4 tsp KNO3 3x a week
+/- 3/16 tsp KH2PO4 3x a week
+/- 1 tsp once a week (water change only)
+/- ¼ tsp (15ml) Trace 3x a week
50% weekly water change

You will simply want to figure out how many doses you want to have in your (about) 1L bottle, and then multiply up the doses.

For example, if you want to have 25 mL doses, then you will have 40 doses in 1L. This means you'd multiply the above (single) doses by 40.

It is generally advised to mix the micronutrients separate from the macronutrients.

Furthermore, you may want to double check solubilities of the salts, as you don't want to oversaturate the solution.

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Rush3737

Discussion Starter · #3 · Mar 3, 2014

Well, I currently use the following dosing:

60-80 Gallons
3/4 tsp KNO3 3x a week
3/16 tsp KH2PO4 3x a week
1/4 tsp K2SO4 3x a week
1/4 tsp (15ml) traces 3x a week

Interesting that Tom doesn't include K2SO4 at all, while this one uses a substantial amount of it. The dosage in the bottle can be whatever is safe to maintain solubility. The ferts I have are from Nilcog and are a powder, so can I assume when you use the word salts its by a purely chemical definition? Because the texture is certainly nothing like typical salt. For dosing, the container has markings at 15ml and 30ml. So I could go in those intervals easily. While 30 would be easiest, if I have to do 60 or 90ml as to cut down the amount of ferts in the bottle to maintain solubility I'm fine with that. And I would of course do two different bottles.

Also, in your post I see "+/- 1 tsp once a week (water change only)" is that for Iron? It doesn't say, but I'm guessing so.

I'll start trying to compute for 30 30ml doses and see if I can figure it out from there.

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Darkblade48

· #4 · Mar 3, 2014

Rush3737 said:
Interesting that Tom doesn't include K2SO4 at all, while this one uses a substantial amount of it.

See below.

Rush3737 said:
The ferts I have are from Nilcog and are a powder, so can I assume when you use the word salts its by a purely chemical definition? Because the texture is certainly nothing like typical salt.

Correct; I am using "salt" in the chemical sense. The chemicals you have will likely not have the same consistency as table salt (sodium chloride).

Rush3737 said:
Also, in your post I see "+/- 1 tsp once a week (water change only)" is that for Iron? It doesn't say, but I'm guessing so.

I think this was for the GH booster that Tom Barr advocates. The GH booster is a mixture of calcium, potassium and magnesium sulfates (and this is where the K2SO4 appears).

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Rush3737

Discussion Starter · #5 · Mar 3, 2014 (Edited)

Thanks.

So using my current dosing schedule (since I don't have GH booster and do have K2SO4) in 30 dosings I would need 22.5 tsp of KNO3, 5.625 tsp of KH2PO4, and 7.5 tsp of K2SO4. This totals 35.625 tsp, which is 175.6ml. This means I would add 724.4 ml of water for a total of 900ml, which would dose out 30 times at 30ml each.

Sound good? Do you think that solubility would be any issue? Also, I've heard people refer to RO water. Online somewhere someone had a video that used boiled and cooled water. If I added conditioner to that would it still work? My guess is it would be bad because elements in the water could react with the ferts. And if that doesn't work, does distilled water from grocery stores work? And finally, if not, does any place other than LFS sell RO water?

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Aqualady

· #6 · Mar 3, 2014

I use distilled water from my grocery store

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Rush3737

Discussion Starter · #7 · Mar 3, 2014

One other question is this, using the calculator from fertilator, why is it that with my formula, which obviously many people use and works, ends up with most things outside the normal parameters?

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Darkblade48

· #8 · Mar 4, 2014

Rush3737 said:
So using my current dosing schedule (since I don't have GH booster and do have K2SO4) in 30 dosings I would need 22.5 tsp of KNO3, 5.625 tsp of KH2PO4, and 7.5 tsp of K2SO4. This totals 35.625 tsp, which is 175.6ml. This means I would add 724.4 ml of water for a total of 900ml, which would dose out 30 times at 30ml each.

Sound good? Do you think that solubility would be any issue? Also, I've heard people refer to RO water. Online somewhere someone had a video that used boiled and cooled water. If I added conditioner to that would it still work? My guess is it would be bad because elements in the water could react with the ferts. And if that doesn't work, does distilled water from grocery stores work? And finally, if not, does any place other than LFS sell RO water?

I did not check the math, but you might run into solubility issues. You're getting close to the maximum solubility of KNO3, and then there will be some common ion effect that might force stuff out of solution.

Also, you don't want to add 724.4 mL of water, as some of the solutes will dissolve into the water (causing volumes to change). An example of this is mixing 1L of water with 1L of ethanol. The total volume is ~1.92L and not the expected 2L. For your fertilizers, the proper way is to top off to your desired volume.

Finally, it is best to use distilled water (grocery store is fine).

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Rush3737

Discussion Starter · #9 · Mar 4, 2014

Sounds good. I'll resolve (hopefully) both issues you presented by making 45ml doses, which at 21 doses would be 945ml, or basically the exact 946ml the bottle holds!

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