BigBamboo, always sorry when this situation happens,Any chance the "oil type" compressor in the shop added to the problem. I seem to always have some oil residue in my shop compressors when I drain them yearly along with a lot of foul condensate.Be sure to match the diffuser to the output of the pump and get a lifting rate on the diffuser at your intended depth so you arent lifting too much water which can diffuse the upper DO down to a lethal rate.In a mature pond that has a high demand for O2 consider placing the diffuser in a depth 50% of the maximum or intended depth during startup and taking it deeper each week, especially this time of year.This may be safer than (from a depth standpoint ) all or none.
