Something leeching phosphates??

[ajtomase]

I've had my tank up for 3 years now, manmade rock, and a finer substrate and I've been noticing that my phosphates will climb at a very rapid rate (day one will be .12, then 2 days later will increase to .2). I feed frozen food and nori daily, and have not changed what or how much I've fed or the frequency. I been keeping phosphates under relative control with Phosphate Rx and I do weekly 20% water changes and siphoning the sandbed. I also clean the filter socks 3x a week.

I haven't had issues with phosphates previously and I'm wondering if either my rocks or substrate are leeching phosphate. Thoughts?

 

[rishma]

I've had my tank up for 3 years now, manmade rock, and a finer substrate and I've been noticing that my phosphates will climb at a very rapid rate (day one will be .12, then 2 days later will increase to .2). I feed frozen food and nori daily, and have not changed what or how much I've fed or the frequency. I been keeping phosphates under relative control with Phosphate Rx and I do weekly 20% water changes and siphoning the sandbed. I also clean the filter socks 3x a week.

I haven't had issues with phosphates previously and I'm wondering if either my rocks or substrate are leeching phosphate. Thoughts?

I find I can spike my phosphate from 0.12 to 0.2 in a couple days by just feeding more than usual. I also think both levels of phosphate are ok, but I do try to keep it closer to 0.1. That’s just because I get hair algae at higher levels, corals actually seem to like it. If you are not seeing problems at 0.2, I wouldn’t worry about it.

It could be your substrate or rock. It binds phosphate over time and will release it. I imagine when the surface is all bound up with phosphate, that phosphate sink is full and more stays in the water from feeding.

 

[Randy Holmes-Farley]

Foods do contain a large amount of phosphate. Feeding can add a few tenths of a ppm in a day.

In this case, the difference could be lower demand (either by organisms or by binding to rock and sand) as opposed to actual release to the water.

Phosphate doesn't suddenly start being released from rock and sand, unless something changes, most notable of which is if you try to lower the phosphate concentration below where it had been.