Sudden High Phosphate in Cycling Tank
I just checked the parameters of my 10 gallon which is still cycling with ADA Amazon II and Powersand. It's been cycling since May 23 and until today nothing looked out of the ordinary. Suddenly this afternoon the PO4 has gone from 0.25 to 5. To be certain it wasn't the tap water I checked that and got a reading of 0.25. I'm not cycling with fish so the only thing in the tank is plants....a lot of plants and two pieces of driftwood which have been in from day one. And the only change is that the CO2 was stopped five days ago due to breakdown of the little pump which diffused it. I've been dosing Florish Excel since I set up the tank and continue to do so. The ph has gradually crept up from a low of 6.8 to a reading today of 7.2. The other parameters are NH3 0, NO2 0.2, NO3 5, GH is below 20 mg/L, KH is 40 mg/L. Any suggestions as to what is going on??? I'd suspect the driftwood but as I said it's been in since day one. Thanks.