Dosing Nitrates and Phosphates in ATO water

Rick Krejci · Jun 24, 2018

I have a Reefer 250 aquarium with a Chaeto fuge and hefty skimmer in the sump. Despite being fairly heavily stocked and well fed, my nitrates and phosphates run at 0 without any intervention.

I decided to try a constant, low, stream of nitrates and phosphates put into my tank by dissolving some sodium nitrate and trisodium phosphate (both reagent grade) into my ATO water. In 5 gallons of ATO, I put enough in such that my nitrates would be 4ppm and phosphates 0.2ppm in the tank if it were all placed in at once. Since the ATO lasts about a week, it makes a nice consistent stream of nutrients for the tank.

I was wondering if mixing both sodium nitrate and trisodium phosphate in the same 5 gallon container is a good idea, or if there is some reaction that would reduce the effectiveness? Things seem to be nice and stable the 2 weeks I've been doing it, with phosphate around 0.02 and nitrate around 2-4 and the corals look happy.

Am I crazy to be doing this rather than running the skimmer part-time (like to keep it running for gas exchange) or dimming the fuge lights?

TIA, Rick

SOCOM · Jun 24, 2018

Sorry I don’t have an answer to your specific question but have you thought about just dosing both?

Rick Krejci · Jun 24, 2018

I have, but my space in my cabinet is limited and am already dosing for Ca and Alk. This just seemed simpler and cheaper, especially since the exact levels aren't that critical.

Randy Holmes-Farley · Jun 24, 2018

Yes, you can mix those and also put them into ATO water.

Rick Krejci · Jun 24, 2018

Thanks, Randy!

Randy Holmes-Farley · Jun 24, 2018

You're welcome.

Let us know how it turns out.

Happy Reefing.

Makers Marc · Jun 27, 2018

Randy Holmes-Farley said:
You're welcome.

Let us know how it turns out.

Happy Reefing.

Randy - so I assume I can do this also with Spectracide Stump remover into my 25g ATO?

Randy Holmes-Farley · Jun 27, 2018

Makers Marc said:
Randy - so I assume I can do this also with Spectracide Stump remover into my 25g ATO?

Yes, but my preference is for a higher grade material, such as food grade.

Makers Marc · Jun 27, 2018

Randy Holmes-Farley said:
Yes, but my preference is for a higher grade material, such as food grade.

Food grade potassium nitrate is what I should amazon?

Randy Holmes-Farley · Jun 27, 2018

Makers Marc said:
Food grade potassium nitrate is what I should amazon?

Yes, that’s a good choice. [emoji3]

Makers Marc · Jun 28, 2018

Randy Holmes-Farley said:
Yes, that’s a good choice. [emoji3]

Randy,

Saw on another post calcium nitrate was an option. Since my salt (aquavitro salinity) seems to have low Ca at 375ppm, would it be better to just get this so I dont have to worry about overdosing potassium?

Randy Holmes-Farley · Jun 28, 2018

Makers Marc said:
Randy,

Saw on another post calcium nitrate was an option. Since my salt (aquavitro salinity) seems to have low Ca at 375ppm, would it be better to just get this so I dont have to worry about overdosing potassium?

It's likely fine either way.

FWIW, Salinity claims higher calcium at 35 ppt. Is your salinity lower?

Makers Marc · Jun 28, 2018

Randy,

My salinity is slightly slower at 33ppt or 1.024sg.

But for the past 3.5 yrs I've used this brand, my Ca always seems to settle at 375ppm. ALK at 7ppm and Mg at 1200.

It's weird. Even raising my salinity to 35ppt and Mg to 1400ppm. Ca and Mg seem to revert back over time.

Randy Holmes-Farley · Jun 28, 2018

Makers Marc said:
Randy,

My salinity is slightly slower at 33ppt or 1.024sg.

But for the past 3.5 yrs I've used this brand, my Ca always seems to settle at 375ppm. ALK at 7ppm and Mg at 1200.

It's weird. Even raising my salinity to 35ppt and Mg to 1400ppm. Ca and Mg seem to revert back over time.

That salinity would give that calcium, so that's not unusual. If you raise salinity you raise alk and calcium too, and that can raise demand for alk and calcium, so they may drop back somewhat after you raise salinity if you do not dose.

Makers Marc · Jul 12, 2018

Rick Krejci said:
I have a Reefer 250 aquarium with a Chaeto fuge and hefty skimmer in the sump. Despite being fairly heavily stocked and well fed, my nitrates and phosphates run at 0 without any intervention.

I decided to try a constant, low, stream of nitrates and phosphates put into my tank by dissolving some sodium nitrate and trisodium phosphate (both reagent grade) into my ATO water. In 5 gallons of ATO, I put enough in such that my nitrates would be 4ppm and phosphates 0.2ppm in the tank if it were all placed in at once. Since the ATO lasts about a week, it makes a nice consistent stream of nutrients for the tank.

I was wondering if mixing both sodium nitrate and trisodium phosphate in the same 5 gallon container is a good idea, or if there is some reaction that would reduce the effectiveness? Things seem to be nice and stable the 2 weeks I've been doing it, with phosphate around 0.02 and nitrate around 2-4 and the corals look happy.

Am I crazy to be doing this rather than running the skimmer part-time (like to keep it running for gas exchange) or dimming the fuge lights?

TIA, Rick

Rick,

How's the dosing going from your ATO? Do you find that the solution settles in your ATO container?

Rick Krejci · Jul 14, 2018

Seems to be going well. Everything's healthy, no algae in the DT and some growth of the Chaeto. My nitrates are staying around 2-4 and phosphates around 0.02. My ATO lasts about 7-8 days and with what I put in there would bring the tank up to 2 Nitrate and 0.4 Phosphate if dosed all at once, so I must be adding more Nitrates than Phosphates with my feeding. My tank has been very Phosphate poor since the beginning, so I don't think there is much if any bound in the rocks.

I have the concentrated solutions from which I dose into the ATO in 1 liter bottles dissolved in RODI water and there is no precipitate in them, so I have no reason to thing anything would settle in the ATO container.

My ATO containers have more of a smell when empty, so I'm a little concerned with all the "fertilizer" there may be some bacterial growth in it.

I like the fact the tank is getting a near constant supply of nutrition, which is my goal, to more mimic natural conditions. I may experiment with upping both a little to see if I can notice increased growth.

Randy Holmes-Farley · Jul 14, 2018

Sounds good!

Happy Reefing.

Steve1500 · Aug 18, 2018

Rick Krejci said:
I have a Reefer 250 aquarium with a Chaeto fuge and hefty skimmer in the sump. Despite being fairly heavily stocked and well fed, my nitrates and phosphates run at 0 without any intervention.

I decided to try a constant, low, stream of nitrates and phosphates put into my tank by dissolving some sodium nitrate and trisodium phosphate (both reagent grade) into my ATO water. In 5 gallons of ATO, I put enough in such that my nitrates would be 4ppm and phosphates 0.2ppm in the tank if it were all placed in at once. Since the ATO lasts about a week, it makes a nice consistent stream of nutrients for the tank.

I was wondering if mixing both sodium nitrate and trisodium phosphate in the same 5 gallon container is a good idea, or if there is some reaction that would reduce the effectiveness? Things seem to be nice and stable the 2 weeks I've been doing it, with phosphate around 0.02 and nitrate around 2-4 and the corals look happy.

Am I crazy to be doing this rather than running the skimmer part-time (like to keep it running for gas exchange) or dimming the fuge lights?

TIA, Rick

I am thinking of doing the same thing w my ATO. You mentioned that you put in enough for 4ppm N and.2ppm P. You meant that you put in enough to raise the levels in your DT to these amounts and not your ATO tank right? Meaning the N and P levels in your 5 G ATO tank was really high right but since you were dosing a few times per day or whatever, it raised your DT only slightly. Did your tank nutrients ever stabilize and you stopped dosing ?

Thanks,
Steve

Rick Krejci · Aug 18, 2018

Correct. It would raise the DT that much if put in all at once. I'm down to dosing 2ppm Nitrates and up to 0.4ppm Phosphates. I have trouble keeping Phosphates up from 0. It seems odd to me since so many people run GFO and struggle with Phosphates. I'm getting some other type of algae growth in the sump (more leafy and lighter in color) and I've just been putting that in my algae feeder in the DT for my Tang. Lots of algae there, virtually none in the DT. I moved a few of my snails down to the sump, so I only have about 3 large turbos and a tuxedo urchin in the DT as my CUC (and the yellow Tang).