Ok guys I still need your help..

I checked the res today and ppms dropped from 1000 to 700 in 48hrs.. ph went way alkaline as well.. I adjusted but that change wasnt very expected at all.. and the plants freaken sucked the color of the nutes out of the resevoir! Water mixed day before yesterday was nice green tint.. today it was clear.

Also noticed the plants most affected are the ones whos roots are now down into the resevoir water.. dunno if its a coincidence or what.

any ideas?