Mustard Algae New to forum

[Lori O]

Hi,
I have a 26,000 gallon gunite/plaster pool. We put it in 15 yrs ago and are just starting to have terrible yellow algae problem. It is difficult to brush off and we have had to resort to using a wire brush (our pool needs resurfacing anyway). The pool store tells me that I have to empty 2/3 of the pool water and start over. I don't want to empty that much because we plan on having it resurfaced during the off season this fall/winter and will have to empty it completely at that time. Obviously we have tried shocking and algaecide. The man at the pool store says that it is over chlorinated. What do I do? I am also having a hard time trying to understand the terms people are using for how much chemical is needed. Can this be done with liquid chlorine bleach instead of the kind you buy at the pool store? This is getting very expensive.

Thanks for your help,
Lori

[BigDave]

Sounds like you may have high CYA. You can manage the pool without draining but fighting Mustard Algae will take a lot of chlorine.

Take a look at Ben's Best Guess Chart (http://www.poolsolutions.com/gd/best-guess-swimming-pool-chlorine-chart.html) - this is the framework for understanding how you'll need to operate.

You'll also need (no substitutes) a Taylor K-2006 (or K-2006C). If you buy it through the links in this thread (http://www.poolforum.com/pf2/showthread.php?14994-How-to-Get-the-Right-Testkits-for-your-Pool) the Poolforum get a few shekels to keep the lights on.