Hi guys, I have a bit of an oddball situation and I believe this is the right thread to get some help beyond the basics .
My Nitrates have always been undetectable (somewhere between 0 and 0,5 on Salifert). My Phosphates have been in the 0,01-0,025 for the most part (Hanna ULR Phosphorus). I cannot get caleurpa or chaetomorpha to grow in my refugium... By now you are all thinking "naturally, as you do not have nutrients for those to grow". HOWEVER, GHA grows all over the refugium (including smothering the chaetomorpha, and killing of the caleurpa) and typically cyano follows after the GHA starts to recede. Also, I have to clean my glass everyday.
The tank is 700 litres plus 200 litre sump, I have about 10 fish and feed pellets 3x a day on an auto doser. As I said, I have never been able to register Nitrates.
On another note, my LPS (Euphylia, Lobophylia, acans) and my huge Letter coral all are doing fine... again, suggesting that nutrients are not that low...? But again. macro algae just does not grow....
My SPS on the other hand are never too happy: very title polio extension, and almost no growth... for acros. Montiporas and seriatoporas grow like weeds and colour up nicely, with great polio extension, my pink poccilopora turned brown but other than that has huge polip extension...so you see the permanent contradictory signs I have.
So what I am thinking is: my phosphate is probably higher than I am measuring (dirty glass). However, my Nitrates are non existant therefore creating the imbalance that messes everything up and does not provide the macros with the required nutrients to grow. Following a Triton test that confirmed my parameters, everything seems to be OK except for Potassium (which I have never dosed...???) which is way higher than it should be at 488ppm... I'm guessing this feeds the GHA but not the Macros?
Feedback from the experts would be greatly appreciated.
Oh, as far as Nutrient export I have a Thrilling Rollermat filter with 5micron fleece that completely filters out the water, a decent Deltec skimmer, a reactor with Fauna Marin Ultra Phos and carbon, and a refugium (which just seems to grow layers of dead GHA, cyano and than more GHA.