I put the seedlings in baskets. I filled the buckets with water, rhizotonic and set the PH to 5.8. On the second day the ph reached 8.0. Probably because of the algae or fungi. I can smell a specific smell from the water. I changed the water. The reason was probably the light coming in through the expanded clay baskets. I printed the lids for baskets on a 3d printer. I hope it will help. Additionally, I added Keep it Cleen to each seedling
ArthurStotch, I was thinking the same. Then I took the basket and looked from underneath through the light and I saw the light on the sides. There are many empty spaces where expanded clay touches the baskets wall. I used Rhizotonic. Yes it's organic but producer says that it can be used in DWC