Roger dodger. I read back through to your initial post.
No pun intended but the root cause of the problem hasn't been corrected. One thing that can help with the poor root environment besides obviously getting the temps in check, would be more oxygenation bad bacteria don't like oxygen. While you can't cram any more air into water with an air pump you can agitate the roots with the bubbles and expose the bad bacteria to unfavorable conditions resulting in their demise. Hydroguard eats organic matter but it won't necessarily innoculate your roots. Mychos will to a degree prevent an encroaching infection by reducing available root surface to latch onto. But if they aren't living on the roots the bad bacteria can still get there. The orca does have a handful of different cultures in it but they really need healthy roots to start getting established. I know your tight on space, so an external rez seems out of the question. You need to get some heat out of the tent. Either by reducing the heat source, or increasing/improving ventilation. If your floor is cool (65°f or less) try insulating your buckets better to help keep temps down. Wrap a towel or blanket around them. If not you could grab a couple more buckets and put your ice in those then nest your dwc buckets in there. You'll get a gradual temp swing but it should keep you in check on a daily basis.