Over the last several weeks had a pretty good bout with mustard algae. Had to raise the clorine level up per the calculators instructions but everything soon began to clear up nicely. Upon returning recently from out of town I found the water crystal clear and looking as good as it ever has. Hadn't tested in a while so I decided to check my readings.
FC - 19 - Still really high since the shock with bleach but auto clorinator still runs with filter on
PH - 6.8
TA - 50
CH - I don't get any reading at all
CYA - 90+ wanted to test again but reagent too low
I am beginning to doubt some of my readings. Test kit is a year old but DPD powder looks dark and Calcium hardness test wouldn't begin to turn water red. just went and bought some baking soda to raise PH and TA. Never had to add calcium since I've had the pool but never go a zero reading either. Any siggestions? Hard to understand the need to keep treating when the pool looks great.