The PO4 Value isn't something you should Actively Chase. Worst thing you can do. I know, I did it and I paid the price (Damaged Corals).
Stable PO4 is most imporant!!!!!!!!!!!!!!!!!!!!!!!!! (Quick Drops are most damaging)
I've had my Tank Phosphate at 0.35-0.4 range, even as high at .5ppm (
BUT STABLE), maybe higher, and this is what it looked like.
This tank thrived and still does in Filthly High Levels of Nitrate (50) and Phosphates (0.5) (
BUT STABLE!!)
Just a SKimmer. No Carbon, No GFO, 2 Part Dosing for ALK,CALC, and Mag.
However that tank was LPS, Mushrooms, and
NO SPS.
Then My other Tank (ONLY SPS), I had problems with. PO around 0.3.
I found and struggled to get PO4 down, and destroyed Frag after Frag (SPS).
NOTHING IS WORSE for SPS than YO-YO phosphate levels. (as you inconsitantly fight the natural level of your Tank Filtration)
Eventually (3+ months ago) I took some advice from a Experience SPS grower and he recommened PO4 between 0.05 to 0.09 (Under 0.1, but stable).
I could ony achieve that using GFO (Quality RhowaPhos). Small amount but every 2 weeks (Religeously).
Small amount of carbon (all the time...NOT TOO MUCH!! )
That got my PO4 Stable at 0.06, and things took off.
NO SPS deaths. Frags Encrusting, Corals Coloring up, and Great PE.
However just to mention. P04 is just part of one Stability you need right.
ALK is just as imporant is not more imporant. Good to keep all other Parameter Stable (CALC, MAG, and NO3)
Water changes, to keep Trace Elements replenished (and export toxins) is another positive step.
Also all this improvement was achieve by NOT adding any junk to tank.
Only food for fish, to make POOP to feed Corals.
NO Coral Feeding, NO Aminos (A bad past habit of mine, that was worst thing I ever did. Short term Positive, long term NEGATIVE side-effects).
SUMMARY: Don't Chase Numbers People Throw at you. A
Work on Achiving Stablity, and that worth the effort and not a easy task (Especially if you tank is not years mature)
