Hi KP

Are you sure that it is mustard algae? With the numbers that you have posted, everything should be good. I personally dont like your CYA at 100 we tell everyone to run at half of that. There have been some great posts on high CYA and Ben has talked about it as well. If it is too high, you need to run higher Chlorine levels. As far as the green pool goes, if you have confirmed that it is algae then that is great. I just had a pool a few weeks ago with almost the same numbers (except CYA) and it was a pretty green colour as well. It was also very clear except for the colour and it turned out that they had used cheap water softener salt to start their pool. I push the use of water softener salt but it has to be the clean white pellet kind not the stuff with pink and brown lumps. In the end, I told them to leave everything alone and the colour went away after about a week of filtering. Check your salt and make sure that it is the right stuff. If it is, the other advice given here is great.

Mark Manning
Watermaid Canada
mark@watermaid.ca
www.watermaid.ca