Phosphates and Nitrates won't stabilize

[chrisd73]

I keep ping ponging back and forth. Phosphates will max out at .90 on the Hanna checker and Nitrates will read 0.0. I have a carbon/gfo reactor running in the sump and will add Phos-E and dose Nyos Nitrates. Readings the next week will be .05 Phos and anywhere between 5-10 Nitrates. Then will hover around there for a week or so, then right back to .90 and 0.0. Is there something I am missing? Tank is almost a year old. 65 gallons, with a couple of clowns, a royal gramma, blue damsel, yellow corris wrasse and a firefish.

 

[Lavey29]

What are you inputting into your system? Pellet or flake food? Reef Roids? Etc... when phosphate is high elevated it can cause difficulty raising nitrates. You see the difference when you bring the phosphate down. Do you wet skim?

 

[Pistondog]

Do you feed reef roids? They are high in po4.
Also po4 gets sucked up by rocks and sand and releases back to equilibrate with water.

 

[chrisd73]

What are you inputting into your system? Pellet or flake food? Reef Roids? Etc... when phosphate is high elevated it can cause difficulty raising nitrates. You see the difference when you bring the phosphate down. Do you wet skim?

Feed pellets. No reef roids. Skim is dry.

 

[Lavey29]

Feed pellets. No reef roids. Skim is dry.

Pellets raise phosphate. Frozen raises nitrates. Dose neonitro because without sufficient nitrates your corals will slowly starve to death.

 

[Randy Holmes-Farley Verified Community Expert]

When you remove a lot of phosphate rapidly (a poor plan, IMO) then you set up a situation where there’s a lot of phosphate bound to rock and sand that will desorb into the water, potentially explaining your rise back.

 

[rishma]

^this

I call it the GFO phosphate yo-yo.

I have found that using small amounts of GFO, and the. adding small amounts of additional GFO as the previous batch becomes exhausted tends to result is a slow, steady, and durable reduction of phosphate.