We've been testing with guess strips for a little more than a year. We've got a pool store with a pretty solid neighborhood reputation that we take water samples to about every other week. They do pH and chlorine readings, but very little else unless we've got a visual problem.
My wife usually tends to the pool chemistry, but I've offered to that that job and purchased the TF Test kit to help.
We had a small bout with algea about 10 days ago, but raised the chlorine level, did some brushing and vacuuming and feel like we are about back to normal.
I ran a set of tests on this past Wednesday...then another today...just to practice with the kit & get a feel for pool chemistry rates of change.
Anyways...here's the data:
FC: 19...............FC: 17
CC: 1...............CC: 0
TC: 20...............TC: 17
pH: 6.8..............pH: 7.2
T/A: 100............T/A: 110
CH: 220.............CH: 220
CYA: 90..............CYA: 90
It's a 24' round pool with a 4' depth. About 13,500 gallons I believe. Sand filter.
We keep a floating pool chlorinator & add a pre-dissolved 1lb package of powdered shock routinely once or twice a week (depending on usage, weather, guess strip readings & feedback from the pool store).
After seeing Wednesday's test results & noting the low pH level, I consulted the poolcalculator (erroneously inputting 12,000 gals), which suggested about 75 oz of Borax to raise the pH. I bought a box & broadcast the whole thing (about 77 oz) into the pool wednesday evening. Our filter runs 7 hours during the day, and another 7 hours while we sleep.
Anyways, the pH moved from 6.8 to 7.2, which was less than I had targeted...but then, I failed to account for about 1500 extra gallons of water. I'll add more Borax this evening & try to fine-tune the pH to 7.5.
My free chlorine remains high, but did fall 2 ppm in 2 days. I'm a tempted to take the floating chlorinator out to allow the chlorine level to fall faster, but because we'll be away for the long weekend, and fresh from a battle with the algae-monster, I'll probably keep it in and let the FC fall slowly.
My wife will want to add another pound of powdered shock before we leave for the weekend (she HATES algae) , but I don't see the need, especially if the pool remains covered and the floating chlorinator remains in.
Anyone see anything else that looks odd or out-of-whack?
Am I sound in my reasoning to resist adding additional powdered-shock chlorine for the weekend, given the Friday morning readings?