Hi
@toematoe Here is a couple of things that may help. Get some covers on the top of the Hugos to keep light off of them otherwise you will get too much algae growth and that is what the fungus gnats eat. I have used lots of things but the FloraFlex cap with a small piece of Orca Grow film work well for me. Remove the Orca film when the plants shade the hole. These caps also make it easy to flush the cubes or add additional nutrients for a fussy plant.
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A problem with flood and drain is salt build up at the water line. If you cannot flood over the top of the cubes you will get a toxic salt build-up inside the cube above the water line. To mitigate this you should top water to drain once a week. I always did this just before a reservoir change. Change the reservoir weekly. Fertigate with every watering. Nutrient strength is learned with your brand but I usually start seeds at 25% first week 50% then 80% from then on. PH is paramount to success. I run 5.8 to 6.1. I have a meter probe in the reservoir 24/7 and check it several times a day. I noticed you are running RO water. Be sure to add 50 PPM of Cal-Mag above your normal addition to replace what the RO takes out.
It is a little late now but I put a teaspoon of Mykos in the hole before I transplant.
Good luck and tag me if you have a question.
Here is my current grow. I use precision drip to waste now.
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