I hate mustard algae

[DavidD]

Sounds like MY experiences with DHL and UPS. To each his own I guess.
If you used copper algaecide "pre forum educated", then you still have copper in the water. I saw where you recently did a partial drain so hopefully the level is negligible. You might think about getting your water tested for copper just to be on the safe side.

Here's my theory on the foam, as I previously stated, I think it is leftover by products in the water. When you "shut the pump off and switch the valve back to the side jets" the combination of the pressure and air mixing with the water and "stuff" creates the foam. Do as I suggested in my previous post and let's see what, if anything changes. Try to bring your FC up to shock level before using the Polaris again.

Dave

[chem geek]

topless,

Would you mind letting me know exactly what your chlorine level was (if you know it) when you saw the algae go away? Was your CYA still at 150 or did you drain and refill some of your pool water before the algae went away? I'm trying to determine what level of chlorine is truly needed to get rid of algae and a very high CYA case such as yours is a good one to help make that assessment.

Ben's table says to shock with 25 ppm of chlorine so I'm wondering if that's the level you believe you attained. Even if you didn't measure the result, you probably calculated how much chlorine to add to get to a certain level so was it 25 ppm that you were shooting for?

Thanks,
Richard

[topless]

Well, it turns out that the package wasn't my test kit. It was a package from customer of mine.

chem geek, I have no idea what my free chlorine level was. The local pool stores just told me it was over 10ppm after 2 gallons of bleach and after I added 6 more gallons of bleach over a 4 day period, it was too high for them to test.

[chem geek]

OK thanks. When you get your own test kit, assuming it's a FAS-DPD test like the one Ben provides, then you will be able to test even high chlorine levels. Just so you know, even the pool store would be able to determine your high chlorine levels if you give them diluted samples of your water, say diluted 4:1 using distilled water which means 1 part pool water plus 3 parts distilled water (tap water would probably also be OK since you would be checking only for extraordinarly high chlorine levels, but tap water will likely either have some low levels of chlorine in it or slightly higher levels of monochloramine which reports as Combined Chlorine, but still wouldn't be more than a few ppm). You would then multiply whatever reading they give you by 4. This isn't super accurate, but is still better than nothing.

[topless]

I hadn't thought of that. If the rain stays away, I'll take a sample in this weekend.