mustard?...sorry long post

[mneal]

This morning I brushed pool and I had slight yellow mustard (I guess that s redundant) on one wall. I checked water yesterday and CC was 4.0. PH was 8.0 so I added 1 cup acid. . This morning CC was 3.0 and pH was 7.7 so I added 1/2 cup more acid. We have people coming by today for BBQ/pool party so I didn't want to shock it yet...is that dumb? I just added a slight (pint) of chlorine and I will shock it tonight. Is I will keep an eye on chlorine today in case the algae is gobbing it up.

[gordyjamz]

Use the polyquat. It worked for me. Got the tip from one of the threads here, and it worked. Thing is, this year its seems the little buggers won't go away with a shock level of cl, so I tried the polyquat algacide. It did cloud up the water once it was killed, but I used a floc to let it settle to the bottom. Vacummed it to waste, and presto, no more algae since beginning of August! Have had clear water since.

[Simmons99]

Polyquat may help - but it really works better as a preventative measure. If it is mustard algae - it will go until you shock to the level appropriate for your CYA level. Then you need to hold it there until the algae dies and the pool clears.

My understanding is that mustard algae is harder to kill than most - so clorine is really the key.