The degradation is real but a little overstated; according to here storing 10% at a constant 90F will degrade to 5% in... not quite 4 months. At a constant 80F it's 8 months. With a pool in the >20K range and no cover, it's not unlikely to be using a gallon a week; if you can store the 10% stuff anywhere below 90F then I think it pretty much comes down to price and convenience of going by the right store.frustratedpoolmom said:Honestly you might be better off sticking with the Great Value brand from Wal-mart - the 5 gallon strong stuff [i.e. the 10%] is a great price but would probably degrade rather quickly before you could use it up.