JMO, but, somewhat with Hara, I would say, Too much bio-load for the bio mass. The food it takes to feed the fish is probably where the PO4
comes from. That, or your water supply.
I never pay too much attention to the alk
in mine because it has always been high and is naturally in my tap.
I use the AquaLabI PH & Alk
test strips and mine are amazingly accurate and stands up to Hagens and Red Sea TK's. The Alk
on the test strips is always above the color scheme on the bottle and the ph is easier to read in normal light.
Why not replace the rest of the CC with sand?
I thought Lace Rock was cool too at one time, you may see a thread in here somewhere, that explains how I found it for .75 a pound and bought a bunch. I soon took it out because I had a problem with buffering capability and went out and bought so far 75 to 100 lbs of LR
est. I do not have problems now. I also have a 3inch SB mixed playsand and aragonite. I say no to lace rock now.
Replace the rock with LR
, get rid of the crushed coral and go with 100% sand. Feed once a day and only what they will eat in 5 min. Make sure the food you feed with is as close to phosphate free as you can. Frozen brine shrimp is saturated with phosphates.....
This is all my opinion.. I hope it helps any.