Rain and algae

[jv4nu]

This is my 2nd year with a pool using bleach. Does anyone have any tips for keeping algae at bay during rainy weather....like should you keep your chlorine levels higher than recommended for your CYA level? I have a solar blanket which I kept on for the last week of cool 60's and rain. My levels were this pretty consistently: FC: I would add bleach to always stay in the 6-8 range pH: 7.6 TA: 110 CYA: 40. I thought I was not letting my FC dip down at all, yet when I took the blanket off after a few days of this weather, I could tell I was at the beginning of a bloom. I am back to clear after keeping my FC 15-20 for the last 48 hours. We'll try for one last swim tomorrow, then the 10 day forecast is highs in the 60s, so I think it's time to call it a season (sniff!)

[chem geek]

Jean,

Are you using a FAS-DPD (or even just a plain DPD) chlorine test to check separately for Free Chlorine (FC) and Combined Chlorine (CC)? It's possible that the rains (and wind, etc.) brought a lot of organic demand and that what you thought was FC was really CC (if you used an OTO test, you can get fooled that way).

Richard

[CrisL]

I find that by using some polyquat (poly 60 type algaecide) at prevention levels, which is about 2 ounces a week per 10,000 gallons, I prevent the late summer bloom I used to get. I start using it in late July or the beginning of August and use about a quart for the summer. If you buy a larger jug, the rest can go toward closing. I keep my chlorine between 2 and 5 ppm most of the time with cya of about 30.

[jv4nu]

I was using Ben's kit, my CC was never more than 0.5 on any given day. The polyquat sounds like a good idea, I will try some of that next fall.