We have a new salt water pool built in the last few months, first fill about a month ago. We're having trouble maintaining chlorine levels even on very cloudy days. The water looks crystal clear to me with no discoloration. No algae visible to me. Our T-15 has been running two days at 50%, though yesterday we switched it to super chlorinate for most of the day. Filter runs about 12 ours. Two nights ago I dropped in 128 ounces of 7.65% chlorox, and had 4 dichlor pucks in the skimmers most of the day. Next morning Chlorine was at .1ppm. Yesterday we put in 4 bags of smart shock, 39% dichlor, at 7:30 pm the chlorine reading was over 3, this morning its back to close to zero. This was overnight, and during the days we've had nothing but clouds and rain. Is it possible I have that much algae or organic matter when the water looks, feels and smells perfect? Any other explanation?
Total chlorine <1
free chlorine .1 ppm
PH 7.5 (using low and slow when it inches up)
total alkalinity 90 (been adding balance 100)
total hardness 120 (been adding balance 300)
about 44,000 gallon pool, saltwater
Pool store appears to have tested for some algaes and slimes with no readings as part of their comprehensive test. There is some residual dirt I can see from the construction when I scrub that we've been filtering and vacumming, but seems relatively little. Any ideas? what gives?