I have a 27k-28k gallon pool with a SWG and for the first 5 years was trouble free. Since last year, we have had recurring algae blooms and from what I have read on this site, I seem to think it must be mustard algae. We had our sand changed last year and everything was fine during the winter but as soon as the water started to warm, our problems began again. Pool chemistry is as follows:
pH 7.2 (I lowered it in anticipation of shocking)
A week ago, there was yellowish green tint to the water and when I brushed, it "poofed" into a cloud. The pool is now a nice dark shade of green.
Assuming this is mustard algae, chem geek's table calls for a shock level of approximately 43 ppm.
This may be an uninformed question, but anyway: Is this safe for a vinyl liner?
Second, How long do I need to keep my shock at this level to rid myself of this scourge? Many thanks for the help.