A couple of thoughts:
There is no consensus on "ideal" levels of PO4. Zero is too little,ime as corals need PO4 for essential life functions;too high is an x factor. Many sucdessful sps keepers try for readings under .05 ppm or so.
Phytoplankton and some copiotrophic algae are limited at less than .02 ppm; some oligotrophic types much lower .
Then there are some algae that use bacteria ,leaching phosphate from rock or substrate . The organic phosphates are most often unmeasured but come into play via degradtion or enzyme activity all ofthese and other things vary from tank to tank.
Calcification is altered at high PO4 levels.Higher PO4 may enable more nitrogen uptake too.
There are too many varying interdependent variables in a tank to define a general most optimal inorganic phosphate level,imo If that were possible we'd still need to contend with the inaccuracies of hobby grade testing.
Even if PO4 is .04ppm as the op's or lower,gfo or other removers can certainly do damage by taking it too low even slowly,ime. GFO also removes silicate and some metals for better or worse.
FWIW, I get good growth and color and very limited nuisance algae in the .02ppm to .04 ppm range with barley detectable NO3 around 0.2ppm. This range with occasional .01ppm readings or .06ppm reading has been part of a very solid 5 year plus run with healthy and vibrant sps I do feed quite heavily and do not presently use any gfo or other chemical removers but would if levels jumped. I dose acetic acid and ethanol for extra bioavaialbe organic carbon and increasd heterothopic bacteria levels.
It should be noted that while surface waters around reef have PO4 at only .005ppm ,it's higher at depths and it's constant as nutrient rich water moves up through the reef and consuming organisms and is diluted more in the sea than in our tanks.
There is no consensus on "ideal" levels of PO4. Zero is too little,ime as corals need PO4 for essential life functions;too high is an x factor. Many sucdessful sps keepers try for readings under .05 ppm or so.
Phytoplankton and some copiotrophic algae are limited at less than .02 ppm; some oligotrophic types much lower .
Then there are some algae that use bacteria ,leaching phosphate from rock or substrate . The organic phosphates are most often unmeasured but come into play via degradtion or enzyme activity all ofthese and other things vary from tank to tank.
Calcification is altered at high PO4 levels.Higher PO4 may enable more nitrogen uptake too.
There are too many varying interdependent variables in a tank to define a general most optimal inorganic phosphate level,imo If that were possible we'd still need to contend with the inaccuracies of hobby grade testing.
Even if PO4 is .04ppm as the op's or lower,gfo or other removers can certainly do damage by taking it too low even slowly,ime. GFO also removes silicate and some metals for better or worse.
FWIW, I get good growth and color and very limited nuisance algae in the .02ppm to .04 ppm range with barley detectable NO3 around 0.2ppm. This range with occasional .01ppm readings or .06ppm reading has been part of a very solid 5 year plus run with healthy and vibrant sps I do feed quite heavily and do not presently use any gfo or other chemical removers but would if levels jumped. I dose acetic acid and ethanol for extra bioavaialbe organic carbon and increasd heterothopic bacteria levels.
It should be noted that while surface waters around reef have PO4 at only .005ppm ,it's higher at depths and it's constant as nutrient rich water moves up through the reef and consuming organisms and is diluted more in the sea than in our tanks.
Last edited:
Thanks.
