Seedlings yellowing, a couple appear to be dying

My seedlings have grown rapidly in the past few days. But I am starting to notice very small brown spots on one of em and a light yellowish hue on the leaves. One of them is wilted and looks like it is gonna die. They are in FFOF and I'm still trying to figure out proper watering, I still cant seem to figure out when they need water and when they dont. I watered them last on friday, but not enough for it to drain out the bottom of the cups. The top layer is pretty damn dry now. I am watering with tap water as it is my only option and I just tested the pH of the tap water and it is high as can be.. 8.5 or so. What can I do!? Should I just use bottled poland spring for the next few waterings until I can get my tap water straightened out?

u might be overwatering, and u MUST get pH up and pH down and a test kit.

i had the same problems

lumpus said:

u might be overwatering, and u MUST get pH up and pH down and a test kit.

i had the same problems

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Damn, I am basically broke now and its sunday so I cant get to the garden store. What can I do for my next watering?? they are gonna need it soon. I will end up going out and getting the pH stuff, but in the meantime will bottled water be ok?