Rapid rooters huh? I started using the root riot brand a few years ago and had phenomenal results. 90%+ success ratio. A few months ago my success ratio started dropping. Nothing major down to maybe 75% or so. A month or so ago I opened a new bag and noticed a strong musty smell. Smelled like mold to me. Even though there was no visible mold. I took the bag back to the store and they had several other ppl. Come in complaining of the same thing. The guy at the store called the supplier and they said the manufacturing process had been changed but the musty smell was ok. Now the bags have a perforation hole in the top corner.
I do not like this new composition of the r/r's I still am only getting 70% or so to live so I am currently trying a few in rockwool cubes.
I ripped a few rr cubes open with some of the clones that were lagging and found fungus gnat larvae in almost everyone that failed to root.
Now I don't know if it is just gnats from my room laying eggs in em which is possible. Or if they are coming contaminated either way I am trying to get away from the rr's and go rockwool for cloning. The way I figure it the hole in the bags is only providing entry for gnats while they are laying in some warehouse and shit, and that musty smell is like a homing beacon for gnats.
One piece of advice I can give you is to try to cut some of the excess cube away without cutting your roots. This will allow the cube to dry out some. I cut the top corners off at a 45 and this helped to dry the stem out which was leading to damping off a while ago for me. Also make sure you pot the cube above the flood line. The roots will find their way down into the water. You may have to hand water for a few days until they do. Those cubes absorb so much water it is not good to have that on the stem all the time.
Another thing if you decide to cut roots later is to leave the taproots if possible. They will regrow fibrous roots later even if they look a little brown now. Any fibrous roots that were dead/brown you probably did well getting rid of.
When I treated heavy with bleach it took almost a week to see healthy new root growth.
Dwc is a recipe for disaster when it comes to root problems. IMO
I know lots of ppl. use it successfully it just seems more finicky to me. Also I can see how it is harder to get rid of root rot cuz you cannot let your roots dry out. Which is the most effective means to clear up rot problems.
Anyways good luck brother. I hope thing start going better for ya.
Finally after a couple of weeks of nonstop rez. changes and shit things are looking soooooooooo much better over here. Words can't describe how good I feel right now. I checked thoroughly last nite and couldn't find a single live aphid so I went ahead and drenched all my moms with azaguard for the gnats.
I have Great new root growth and lush foliage.
happpy happpy happy
I am also really liking running the dyna gro for the first 4 wks of flower so far. Far less leaf drop and overall they just look better. Still run dynabloom from5 wks on though. I may mix it 50/50 with the grow next rez change.
I can already tell with the mats and new trays I will be able to go back to 1xday flood if not more
Enjoy your last few moments on this earth gnats and aphids...... Soon you will all be dead
sorry for the super long post
Edit: I have never been a fan of foliar feeding. It seems I am always battling high humidity as it is. I don't like to give mold spores any more help to thrive.
My babies be gettin great drainage now. 
..........................so far anyways That imidacloprid is some bad shit. Didn't touch the gnats tho. 
I think I am going to do 2x every other day for a while and see how things go.