Ultra Pool Magic?

[Winglessflight97]

Thanks for a quick response! Each time I've shocked, (I'm working on number 4 now...) I've sustained more than 5-10 ppm throughout the whole time. I've gotten it swimmable each time, only to have algae show up the day after when i return home from work. My test kit(s) don't read precise above 5 ppm. Does that matter? I've seen the Best Guess Chart, and kept it in mind, but i still get algae. I've never had my pool completely sparkling, but it looked very good and could easily see the bottom (6.5 ft deep), even after over a week of shock/filtering, so i'm assuming my filter element needs replacing. I just bought this house over a month ago. Here are my current readings using the Taylor OTD kit:

pH 7.8,
Cl over 10 ppm,
Alk 100 ppm.

Test strips read:

Calcium Hardness: 500 ppm
Total Cl: 10+
Free Cl: 10+
pH : ~7.8
Alk: 80-100ppm
CyA: 30-50 ppm

Thanks for all advice. Like i said, I'm waiting for my 2006c kit for more complete testing.

[madwil]

it sounds like you didn't finish shocking- when the green color goes away, it means you're beating the algae but there is still some lingering. The overnight drop test (lose <1ppm FC overnight) is how you know the algae is dead- you need to maintain shock levels until you pass the overnight test, and have <.5 CC (TC - FC)...
when you have algae, it consumes your FC faster and then the algae takes over- it can take a lot of chlorine to kill a batch, if at all, if you don't maintain the shock levels...

[Winglessflight97]

I think that's been my problem. I haven't maintained shock long enough. Nobody ever told me about the overnight drop. I learn something every day! I really appreciate all the inputs.