How to mix Sodium Nitrate& Potassium Phosphate

IvanW · Oct 12, 2017

I am sure this has been asked and answered somewhere I just can't find an easy answer. I am going to start dosing the above two products which were purchased through Etsy (RHF recommendation). Before I go any further I need to retest Phosphates and Nitrates before I start.
My question is how,in what proportions do you mix these products with water,and I take it, that it is better to dose with a dosser over the course of a 24 hour period.
Total system volume is 650 gallons,not sure that is relevant.

Randy Holmes-Farley · Oct 12, 2017

I doubt you need a doser and once a day should be fine. But a doser certainly won't hurt

Any amount of freshwater that the needed dose dissolves in is fine. They are pretty soluble.

Here's a calculator. They don't list an entry for sodium nitrate, so use the entry for potassium nitrate and multiply the dose by a factor of 0.84 (so dose 0.84 grams instead of 1.00 grams, if 1.00 grams was the desired dose of potassium nitrate).

http://www.theplantedtank.co.uk/calculator.htm

IvanW · Oct 12, 2017

Thanks for the info. If I dose on a once a day schedule till the desired levels are reached,does this shock the tank in any way. Would lets say 3 times a week be preferable or does it not make any difference and can both levels be raised together.

Randy Holmes-Farley · Oct 12, 2017

Both can be raised together. IMO, once a day is a good plan.

IvanW · Oct 17, 2017

I started dosing Sodium Nitrate and Potassium Phosphate. I went to check the phosphate levels,I use a Milwaukee tester and when I mixed in the reagent it turned the water a light blue, obviously I did not get a good reading. Do you know if this is normal?

Randy Holmes-Farley · Oct 18, 2017

What color does the Milwaukee test get? The tests I've used turn blue.

IvanW · Oct 18, 2017

Color is usually clear. With the blue color I presumed it would give a false reading am I correct in my assumption.

Randy Holmes-Farley · Oct 18, 2017

IvanW said:
Color is usually clear. With the blue color I presumed it would give a false reading am I correct in my assumption.

In most phosphate tests, phosphate shows as blue. Maybe you just have more phosphate than usual.

IvanW · Oct 20, 2017

Thanks for all the help Randy,but I have one more for you. I dosed Potassium Phosphate (Monobasic) about 3 or 4 times,as per the calculator 1/4 tsp dissolved in 3000 ml of water.I checked phosphate this morning and it was at 1.48meg/l, I realize that this is a little on the high side,so will wait for it to drop. Is it common for the Phosphate level to go up that rapidly by adding a total of 1 teaspoon to a system that had undetectable levels.This is still a learning curve for me. Just fyi I am trying to bring Phosphate and Nitrate levels up as I have a Dinoflagellate problem (be much easier to take Pepto Bismol for it? No Dr you have missed the point.........)

Randy Holmes-Farley · Oct 20, 2017

IvanW said:
Thanks for all the help Randy,but I have one more for you. I dosed Potassium Phosphate (Monobasic) about 3 or 4 times,as per the calculator 1/4 tsp dissolved in 3000 ml of water.I checked phosphate this morning and it was at 1.48meg/l, I realize that this is a little on the high side,so will wait for it to drop. Is it common for the Phosphate level to go up that rapidly by adding a total of 1 teaspoon to a system that had undetectable levels.This is still a learning curve for me. Just fyi I am trying to bring Phosphate and Nitrate levels up as I have a Dinoflagellate problem (be much easier to take Pepto Bismol for it? No Dr you have missed the point.........)

What are the units? 1.48 meg/l. mg/L?

IvanW · Oct 20, 2017

Should be mg/L

Randy Holmes-Farley · Oct 20, 2017

That's a huge level.

I'm confused. What exactly did you add to what?

IvanW · Oct 20, 2017

I mixed 1/4 teaspoon Potassium Phosphate in 3000ml of water and added it to the sump.

Randy Holmes-Farley · Oct 21, 2017

That was a lot to add at once (too much, IMO).

The calculator I linked above shows that 1/4 teaspoon potassium phosphate in 650 gallons would boost phosphate to 0.47 ppm phosphate.

IvanW · Oct 21, 2017

I guess the screw up was mine. Even with the level that high the inhabitants look no worse for it,in fact I might have inadvertently killed off the Dino problem, as the mat on the sand bed has gone from a lightish brown to a very dark brown. I am going to try siphon it out and see what happens after that.

Randy Holmes-Farley · Oct 21, 2017

IvanW said:
I guess the screw up was mine. Even with the level that high the inhabitants look no worse for it,in fact I might have inadvertently killed off the Dino problem, as the mat on the sand bed has gone from a lightish brown to a very dark brown. I am going to try siphon it out and see what happens after that.

Very high phosphate isn't always a problem, but I wouldn't add more for a while.

t5Nitro · Apr 2, 2020

Bringing back an old thread, but I tested my phos at 0.02 and I have a bad dino algae problem. Looking to increase the phos. When you said you bought off etsy, is this what I'm looking for? Any updates on how this worked out for your system?

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Randy Holmes-Farley · Apr 3, 2020

t5Nitro said:
Bringing back an old thread, but I tested my phos at 0.02 and I have a bad dino algae problem. Looking to increase the phos. When you said you bought off etsy, is this what I'm looking for? Any updates on how this worked out for your system?

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Yes.

t5Nitro · Apr 6, 2020

@Randy Holmes-Farley I received the trisodium phosphate today. I have a 75g display and 20 sump. I added 1/4 tsp of the powder and dissolved it in some water and poured it in. Checked my phos this evening at 0.56 ppm by Hanna ULR. It was 0.02 last week Saturday, granted there are some confounders. I have been skimmerless since that time. I also scraped a lot of dinos/algae off the bottom glass today which may have released a lot of nutrients. Did not pre-test the phos before the supplement just to conserve the very limited test kits you get with these testers. Now I'm thinking I should have tested. Do you think 1/4tsp in this volume of water would reallse cause upwards of 0.5ppm increase? I checked one of the online calculators and thought 1tsp would raise the phos bout 0.04ppm in 75 gallons of water.

Edit: I looked at the calculator again, still doesn't seem to add up to me. I think I mixed 0.25tsp Na3PO4 with 100mL tank water, swirled it and dumped it in. Looking at the above calculator in an earlier post, with 75 gallons of tank water, each 1 mL should increase phos by 0.04ppm. Pouring to full 100mL should raise it to 4ppm then, but I'm still at 0.56ppm. What am I missing on this equation? Is 0.56 bad? Should I be doing some water changes?

Shirak · Apr 6, 2020

Sounds about right based on my calculations when using trisodium phosphate. I don't know offhand how much 1/4tsp weighs but .25g of the stuff should raise 75gal about .5ppm