Starting Trisodium Phophate and Calcium Nitrate dosing, need help with recipe

kishstl · Feb 15, 2023

As my tank is growing I'm fighting with very low phosphate and nitrate. I have been feeding more and adding reef roids and AB+ but still have very low numbers. Just received my Na3PO4 and Ca(NO3)2 from Loudwolf. I have looked for a calculator/recipe but can't find one for these reagents. Any help would be appreciated. approx 85 gal water volume and almost undetectable values for both.

Thanks!!!

P.S. Also dose Kalk through ATO

Randy Holmes-Farley · Feb 15, 2023

kishstl said:
As my tank is growing I'm fighting with very low phosphate and nitrate. I have been feeding more and adding reef roids and AB+ but still have very low numbers. Just received my Na3PO4 and Ca(NO3)2 from Loudwolf. I have looked for a claculator/recipe but can't find one for these reagents. Any help would be appreciated. approx 85 gal water volume and almost undetectable values for both.

Thanks!!!

As a rough guide, you can use this calculator and the entry for phosphate from potassium phosphate and nitrate from potassium nitrate. The values will be close enough for our purposes.

James' Planted Tank - Dosing Calculator

www.theplantedtank.co.uk

Corrections are not needed, but if you did want to correct the calculated dose, the nitrate dose will use about 81% of the recommended dose to the tank.

The phosphate correction is not worth bothering with since so much gets bound to rock and sand anyway.

kishstl · Feb 15, 2023

Perfect. I looked at that one but didn't know if the amounts would be the same.

THANKS!!!

GuppyHJD · Feb 25, 2023

Randy Holmes-Farley said:
As a rough guide, you can use this calculator and the entry for phosphate from potassium phosphate and nitrate from potassium nitrate. The values will be close enough for our purposes.

James' Planted Tank - Dosing Calculator

www.theplantedtank.co.uk

Corrections are not needed, but if you did want to correct the calculated dose, the nitrate dose will use about 81% of the recommended dose to the tank.

The phosphate correction is not worth bothering with since so much gets bound to rock and sand anyway.

Hello Randy,
I am using Sodium Phosphate Dibasic (2 tsp in 1 gallon RODI) dosed at 10ml to raise my phosphate 0.05 ppm per the calculator above. When I test, I am still getting a 0.0 reading using a Salifert Phosphate test. I cannot use the Hanna Phosphate checker because I have high silicate in the tank. Is there a concern with adding too much of the phosphate at a time to the tank? Can I double my dose to 20ml and test an hour later etc.?
Thank you

JGT · Feb 26, 2023

Seems like the accuracy of the calculator isn’t that precise but I guess close enough for dosing purposes.
If I select 250 US GALS, Potassium phosphate into 1892 ml of water (1/2 gal) and want to raise PO4 by .01 ppm, adding anywhere between 2 and 5 teaspoons yields the same .01 ppm results. So then do you use 2 or 5?

Randy Holmes-Farley · Feb 26, 2023

GuppyHJD said:
Hello Randy,
I am using Sodium Phosphate Dibasic (2 tsp in 1 gallon RODI) dosed at 10ml to raise my phosphate 0.05 ppm per the calculator above. When I test, I am still getting a 0.0 reading using a Salifert Phosphate test. I cannot use the Hanna Phosphate checker because I have high silicate in the tank. Is there a concern with adding too much of the phosphate at a time to the tank? Can I double my dose to 20ml and test an hour later etc.?
Thank you

Yes, I'd add more.

Using the Hanna, what do you get? If there is an effect from the silicate, the response will be reading too high, not too low, so a low phosphate reading still means too low.

Randy Holmes-Farley · Feb 26, 2023

JGT said:
Seems like the accuracy of the calculator isn’t that precise but I guess close enough for dosing purposes.
If I select 250 US GALS, Potassium phosphate into 1892 ml of water (1/2 gal) and want to raise PO4 by .01 ppm, adding anywhere between 2 and 5 teaspoons yields the same .01 ppm results. So then do you use 2 or 5?

Yes, it cannot read to better than 0.01 precision. So it rounds the answers to the nearest 0.01 ppm phosphate.

If you want better precision, you can input 10x as much for one of the entries (such as volume dosed) and then divide the answer by 10.

Doing this, I can see that for 3 teaspoons, 10 ml dosed gives 0.08 ppm, 4 teaspoons gives 0.1 ppm, and 5 teaspoons gives 0.13 ppm. Diving all of them by 10 shows that 4 teaspoons will give 0.01 ppm. The others are above or below 0.01 ppm.

Bear in mind this can only estimate what is added, not how much will remain after much of it binds to rock and sand.

tgn225 · Sep 7, 2023

Apologies for reviving this thread, I have filled out the calculator and have a question.

My current parameters are as follows:
NO3: 0.01mg/L
PO4: 0.003mg/L
Net Water Volume: 265L

I am using a stock solution of 85g/L for NaNO3 and 1.88g/L for Na3PO4.

It is telling me to add 40.5ml of KNO3 which would be 40.5*0.81=32.805mL of NaNO3
and 239.5mL of Na3PO4.

It is my understanding that this will get me to an ideal Redfield Ratio but I am unsure of what those final targeted values of nitrates and phosphates will be. Can this be safely dosed all at once or should I spread this throughout the course of a week?

Randy Holmes-Farley · Sep 7, 2023

There is no such thing as an ideal Redfield ratio, IMO. I strongly advise to ignore ratios as they are often misleading and just target absolute values.

I’d aim to start by adding a few ppm of nitrate and 0.02 ppm phosphate each day for a few days and see what happens.

tgn225 · Sep 7, 2023

Randy Holmes-Farley said:
There is no such thing as an ideal Redfield ratio, IMO. I strongly advise to ignore ratios as they are often misleading and just target absolute values.

I’d aim to start by adding a few ppm of nitrate and 0.02 ppm phosphate each day for a few days and see what happens.

Thanks Randy! I am struggling to keep up my nutrients and my hanna checkers and ATI-ICP test states that they're undetectable. Looking to hover around 10ppm NO3 and .06-.08ppm PO4

JoJosReef · Sep 7, 2023

I'm unsure about conversions for this calculator if I'm using Ca(NO3)2 and the calculator is returning ppm for KNO3. For example, I have selected KNO3 in 30 US gal, 42g in 45mL = 5.04ppm nitrate per 1mL dosed. What is the conversion to calculate ppm for using Ca(NO3)2? KNO3 has 61.3% of weight as NO3, and Ca(NO3)2 has 75.6% of weight as NO3. Add about 15% less?

Thanks!

EricR · Sep 7, 2023

My personal opinion is that you're more likely to end up dialing in your dose based on testing over getting it exactly right based on calculations.

I go with the following to end up with mixes that are somewhat in the ballpark of same potency as Brightwell NeoPhos and NeoNitro:
-- 0.5 tsp of Trisodium Phosphate (dry) into 1 L of RO/DI water
-- 113 grams of Calcium Nitrate (full 4 oz bottle) into 500 mL of RO/DI water

*don't take any of that as gospel, just what has worked for me, personally

Randy Holmes-Farley · Sep 7, 2023

JoJosReef said:
I'm unsure about conversions for this calculator if I'm using Ca(NO3)2 and the calculator is returning ppm for KNO3. For example, I have selected KNO3 in 30 US gal, 42g in 45mL = 5.04ppm nitrate per 1mL dosed. What is the conversion to calculate ppm for using Ca(NO3)2? KNO3 has 61.3% of weight as NO3, and Ca(NO3)2 has 75.6% of weight as NO3. Add about 15% less?

Thanks!

Calculated values for nitrate from calcium nitrate are close enough to nitrate from potassium nitrate to ignnore the difference since you will adjust the dose based on results.

OceanDreamer · Nov 4, 2023

Do you think its ok to create a single solution with both Ammonium Bicarbonate and potassium phosphate? Can I mix potassium phosphate with the ato RODI water container?

Randy Holmes-Farley · Nov 4, 2023

OceanDreamer said:
Do you think its ok to create a single solution with both Ammonium Bicarbonate and potassium phosphate? Can I mix potassium phosphate with the ato RODI water container?

What type of potassium phosphate?