Phosphates question

dstahla733 · Jan 18, 2026

Recently upgraded to a used 175 gallon from a 45 gallon. First few days numbers were good so I transferred everything over. Phosphates are now reading 2.5 from my usual .04. Would this be because this tank was torn down around Christmas and all the live rock was dried out? In my mind it makes sense that there were dead inverts all over the rock most likely that is probably breaking down now. Any ideas or suggestions on how to proceed and protect everything? Acros are mostly fine, Millie is closed up, chalice is ticked, and gsp is spotty. Favias and zoas and BTA seem happy as can be.

not_eman209 · Jan 19, 2026

It could be your dry rock leaching phosphate. I’m sure someone more experienced will chime in soon enough. I ran phosguard in a reactor when my tank crashed and everything died to get it back down again.

everyday44 · Jan 28, 2026

I would think you're correct, phosphate binds to rock/sand. Recommend decreasing phosphates slowly, nothing good comes fast.
I would try some Phosphate Rx or Phosphat-e (liquid), GFO if you have a reactor or want to put the bag into a high flow area and knead it everyday to make sure media is being used up.
A little more about the liquid products, it is lanthanum chloride so it needs to be used very carefully and slowly. Follow instructions and dilute the dose into some RODI water. Put drops into a high flow area like a filter sock in the overflow area/protein skimmer neck(where the bubbles are). Lanthanum chloride binds to phosphates and causes precipitate which could cause fish/coral irritation.