High PH

[mattlandry]

I was recently inspired to try a hydroponic setup for tomatoes (Dutch buckets). I am currently having issues with PH. I used PH down to get the PH just below 6.0, but the next day it is back up to 8.0. I have tried with a new nutrient solution, but with same results. Any idea of what may be causing the rise in PH? Noticed a little green algae on the perlite, so added covers to the buckets. Also, noticed upward cupping on the leaves of the tomatoes.