corals starving?

[tasos]

I deal with a problem in my 150 G mainly sps tank with a few ephylias, trachyphilias plerogyra sinuosa and a fungia.
There is a sump with a refugium with plenum dsb aragonite-mineral mud and chaetomorpha above it.Skimming is done with a aquamedic shotry 5000 rated for 250Gs.A EHIEM 2213 (small for this tank) canister with activated carbon and fluidised rowaphos.Ca350, alk 4meq,Mg:1300ppm, NO3:0, PO4:0, Str slightly detectable, ph 8,1-8,3 at noon.Circulation 15X and a tunze wavebox.
I have problem with sps that I feel they don't grow enough, Trachyphilias that just live without growing .I do have enough sponge formation on the glass and LR,I have slight cyano development, and my skimmer doesn't take out much ....I placed another skimmer(deltecMCE 600) on the refugium and then at the main tank, but couldn't produce much skimmate apart from the times I dosed the tank with coral food( frozen) .The chaetomorpha don't grow since a 2 month period now.
Is that a sign that I need to feed more the tank?There are only 6 cromis and 2 tangs in there.I tried target feeding the fungia and now seems better( it had an infection on the mouth that had revealed the septae-now is OK......

 

[kevinpo]

Hello,
LPS corals really do best (long term) when target fed on a regular basis or in a tank with a larger bio-load than you have. Most SPS corals do quite well with much less food.
I would recommend you raise your calcium to 400-425ppm not so much to increase growth but rather to be in better ionic balance with your magnesium and alkalinity.

You don't mention your lighting but a standard 150 gallon tank in the US is quite tall (30") and I would recommend 400W halides for good growth of high light SPS corals. The LPS corals would be best placed towards the bottom if using 400W halides.

IME the removal of too much phosphate can slow the growth of stony corals and even contribute to STN in some Acropora corals.

The environment of many SPS and LPS corals can be quite different from each other so it can be a challenge to provide the ideal parameters for both in the same tank.

Regards,
Kevin

 

[tasos]

I don't use halides, I have 330 Watt T5 hanging 17 '' over most sps, my main tank is 100 G and the sump is 50 G,sorry....
I maybe taking out too much PO4 (30% more rowaphos than needed).........
I will check the calcium, thanks!