Had some green algae spotting on walls. Water clear. Water temp=79, pH=7.3, TA=70, CH=225, Borate=40, CYA=29. I SLAMed yesterday. I did an OCLT. Prior night's results: FC=12.5, CC=1.0. I ran FAS-DPD test 4 times this am, same water sample: FC=10.5, CC=1.0; 12.0, 0.5; 10.0, 0.5; 10.0, 0.5. I called it a failed OCL and brought FC back up to 13 according to PoolMath calculator. My question is, how repeatable is FAS-DPD on 10ml sample? Especially in light of the </= 1.0 FC loss I am testing for. Should I do a larger sample for OCLT? Should I always see un-dissolved DPD powder in bottom of cylinder after adding and swirling DPD, to ensure saturation? Thank you folks for your time and attention. RU