The hydro shop near my house isn't open on Sundays, is it detrimental that I get this done today, or can it wait until Wednesday when I have a day off work? If it can't, what can I get at a local Wal-mart or Home Depot that will give me my desired PH level? I'm almost certain that I can't use the same PH adjusters that are used in a pool. Yet again thank you for your input and suggestions.