Repeated phosphate spikes

[cleverrev]

I got the Hanna UL checker to finally get more precise readings for phosphate. My phosphate was .5 which I thought was high based on research so I began to bring it down with Phosguard.

After adding phosguard the readings began to drop over the span of a few days until they got down to .17. The next day I did a test and it said .72!

I added fresh Phosguard and watched the readings drop again this time down to .21. I tested this morning and it’s back up to .77!

I feed daily so I can’t find a correlation to the spike and anything I am doing or putting in the tank. Nitrates remain steady between 9-12ppm.

Any ideas?

 

[bushdoc]

One possibility is that your rock is leaching phosphates, you lower it down to a point, phosguard gets saturated and cannot keep up with constant influx of phosphates released from rocks. You should eventually keep up, but another option would be to change to GFO in a media reactor or consider Lanthanum chloride dosing, the latter needs some research how to do it.