@1stmanny, I drilled a hole in the bottom corner of the tray to drain out the ~1/4 inch standing water into a dish and tested it with my PH meter.
I had standing water because I was having issues balancing temp with my electric heating pad under it. On low, it was not warm enough but on the medium, it would evaporate all the water and dry out the cubes in short order. I got lazy and instead of just watering a little every day to keep up with evaporation I just overwatered it which never gave the Rockwool a chance to get below 100% saturation.
I have not been adjusting the PH of my clone water for quite a while. My tap water usually is 6.6 pH and ~30 ppm. So I was surprised to see the runoff I drained from the tray was 7.5
Since then I have been pHing the water I give them to about 5, and testing the little bit of runoff. it has slowly come up down from 7 to 5.5.
Not sure how much that had an impact. I was more concerned about the overwatering. They have recovered now so I am happy.
I grow in hydroponics only. Ebb and flow flood table, yes. A couple of under-the-bed storage totes filled with expanded Hydroton clay pellets in a 100cm by 100cm tent. Flood for 15 mins every 3 hours. Been doing that for about 3 cycles now since switching from individual DWC buckets.
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