Phosphate high, low nitrate - how to balance?

[WallysWorld]

My nitrates have tested zero for 3 months, while my phosphates have spiked to 0.5 ppm and now at 0.3 ppm
after several water changes. I am very confident in my testing and have validated results using different test kits.

I have a fair amount of algae. I’m assuming that is why Nitrates are zero. Do I worry about higher phosphates? How do I slow down algae growth and remove it?

I have 5 month 65 gallon tank. Lightly stocked; two clowns, Royal Gramma, lawnmower blenny, small leopard wrasse. A clean up crew consisting of a fighting conch, a couple dozen assorted snails and several hermits. I feed a small amount of pellets twice a day on an auto-feeder, and half a cube of frozen mysis daily. I’m dosing half the recommended NoPox dose daily.

 

[blaxsun]

GFO in a media basket or media bag in the sump.

 

[brmc1985]

GFO in a media basket or media bag in the sump.

This is the answer for the short term. Long term you need to just keep an eye on them and see if they are elevated because of leaching(should stop in a couple months) or it could be your food is unbalanced(ongoing problem).

 

[Randy Holmes-Farley Verified Community Expert]

It's not a particularly unusual situation to need to export phosphate. I used GFO 24/7 for years.

Two reasons for this are that:

1. Denitrification removes N and not P.
2. Many folks have rock that has substantial phosphate bound to it that takes a long time to deplete.

Becaaue of the issues relating to #2, water changes do not deplete phosphate nearly as much as they deplete nitrate.

 

[WallysWorld]

Do I need to be concerned about using GFO with NoPox?

 

[sixty_reefer]

@WallysWorld What’s your current ph and no3 if you don’t mind me asking?

 

[Randy Holmes-Farley Verified Community Expert]

Do I need to be concerned about using GFO with NoPox?

No, as long as phosphate does not get too low.

 

[WallysWorld]

@WallysWorld What’s your current ph and no3 if you don’t mind me asking?

last measurement results May 9, 2022
Nitrate - 0.0 ppm (mg/L)
Phosphate - 0.28 ppm (mg/L)
PH - 8.21
Alkalinity - 11.0 dKH
Salinity - 34 ppt
Temperature - 78.39 °F
Calcium - 470 ppm (mg/L)
Magnesium - 1360 ppm (mg/L)

 

[reefyreef]

No, as long as phosphate does not get too low.

What happens if phosphate gets too low? I was using Seachem Phosguard to get my values a bit low and was thinking about using nopox to slightly lower nitrates.

 

[Dan_P]

My nitrates have tested zero for 3 months, while my phosphates have spiked to 0.5 ppm and now at 0.3 ppm
after several water changes. I am very confident in my testing and have validated results using different test kits.

I have a fair amount of algae. I’m assuming that is why Nitrates are zero. Do I worry about higher phosphates? How do I slow down algae growth and remove it?

I have 5 month 65 gallon tank. Lightly stocked; two clowns, Royal Gramma, lawnmower blenny, small leopard wrasse. A clean up crew consisting of a fighting conch, a couple dozen assorted snails and several hermits. I feed a small amount of pellets twice a day on an auto-feeder, and half a cube of frozen mysis daily. I’m dosing half the recommended NoPox dose daily.

If you have low NO3, why are you dosing with NOPOX?

 

[Randy Holmes-Farley Verified Community Expert]

What happens if phosphate gets too low? I was using Seachem Phosguard to get my values a bit low and was thinking about using nopox to slightly lower nitrates.

Corals will suffer and dinos becomes more of a threat, but 0.03 ppm is plenty and you are still 10x that level.

 

[anthonymckay]

Whats the phosphorus contents of the pellets? They tend to be a big source of phosphates in a tank and controlling what's going into it is the way to fix the issue long term. Def cut back on the pellets if the have a decent amount of phosphorus, feed more protein type foods to get your nitrates up.

Also keep in mind that you should remove as much algae as you can by hand. Killing off the algae without removing it will just release all the phosphates of the algae back into the water as it breaks down and feed the next cycle of algae outbreak.

 

[sdreefer619]

If you have algae your wasting your time testing in my opinion. Water, where are you getting it from. Water changes, filtration, dosing, manual removal, fish, do you have any tangs in there? It’s a loaded question algae is anyway. How much are you feeding. Flake food frozen both?