We are also new pool owners and are fighting mustard algae. We have a 27,600 gallon IG with a Hayward S240 Sand filter, vinyl liner, pump size is AO Smith 1 HP 3450 gallons per minute with a flow rate of 63 gpm. After vacuuming for the 4th time in 7 days, our chlorine level is 1.2 Ph 7.5 Alk 90 Ch 180. Please help!!!!