In my Hydro Setup, I let them sit in plain phd water for about half a day every other day. Have extra buckets to transition easily. I also leave my top bucket sitting on my lower bucket and lifted for about 10 minutes everyday for fresh air. With Gh WaterFarm Bucket ) Doing all that helps with nute burn and avoiding roots drenched in nutes a whole week. Been doing Hydro for about 2 years, always resorted to that and I've avoided nutrient deficiencies, well, major deficiencies.
Thought it might help you with yellow leaves, which could be a sign of plenty things.
What nutrients do you use?