HELP, Wilting perhaps Fungus(EEK) Should I flush?

Hi guys, Just started my first RDWC 5 days ago, and ive got 8 XXX Bubba Kush rooted clones growing in an 8 pot DIY undercurrent system. Im running Current Culture's, Cultured Solutions(UC roots and VEG A/B) and following their nutrient schedule. Im using a new RO system with water at no more than 3 ppm. 2 600 watt HPS, ppm at 150 , ph 6.o, my lights are 3 feet from the plants and have been running 22/2 . Everything is finally in working order i'd say. Im seeing a slight wilt in my plants and maybe perhaps a little yellowing, Im not sure the top parts of plants are just really light green (which are about 6 in. high right now). Id say i already know the cause of the problem, I ran the system for the first 4 days without a chiller and my water temps couldve reached a max temp of 85 F (EEEEK) . Ive got my system chilled now and the water is at 68 deg. Roots have finally reached the bottom of the net pots and are peeking through, but ive noticed a small amount of white powder at the base of my stems on the rapid rooter. (along with the wilting and yellowing which i assumed was purely because of the water temps) I was sure my plants would pull through once i brought the chiller in but now im not so sure, I feel foolish for jumping right in but i have to say im excited and thought I could fight the heat with Ice cubes (water bottles) <-- TERRIBLE INFORMATION there i might add.. does not work and its very stressful. Should i Flush with uc roots and RO water? Im not sure what the powder looking stuff is, I was wondering if it couldve been a powder used to root the clone that has just left a sediment. My roots only recently finally reached the water, could it be this is all stress from the roots trying to reach the water level?

Any suggestions will help. Open to any information! First time grower here guys. Sorry to bump my own post but the white fungus is scary. Ive soaked the top of the rapid rooter and the portion of the stem that has the fungus with a solution of 1 gal RO water / 1 tbs baking soda as a homemade fungicide. Hope im over reacting and this white powder is normal but my gut tells me i should take action. Humidity levels are dropped (35% and temps are up around 77), as to inhibit the growth of the mildew.

Well the mildew wasn't good but flushing with baking soda is what killed it.

Next time keep the stem free of mildew... And if it happens don't freak out and change the PH of your root crown so basic. Nutes get locked out at 6.3.. What were you 12+???

A PH'd, diluted peroxide solution would have been a better choice.

Well i only flushed last night and baking soda is a ph of 7.08 I didnt think it was too basic to use in small amounts just on the surface. But I can flush the baking soda with PHed water if you think i should now

ahh not flushed last night, I meant to say i only used the baking soda water mix last night. I have not flushed my week one nutes. I had someone say they thought the white powder was maybe a rooting powder precipitate?

@SnaFuu I had a cal mag def... my RO water was too pure and the cultured solutions mix was was designed to be able to also be used with tap water at 100-150 ppm my water was too pure for the poor fuckers and i finally caught on today and dosed it accordingly ppm is now up around 300. I think the white stuff i was seeing is precipitate from the powder cloning solution used to root the buggers. I made a solution of PH'd water at 5.5 and UC roots which is sterilizing. Its a multipurpose root zone optimizer that uses proprietary chemistry to aid in mineral descaling and the removal of potentially harmful biofilms in nutrient reservoirs. By reducing the potential habitat for plant pathogens uc roots has been shown to aid in root development. I took that solution and doused the plants in the areas where i had mistakenly put the Baking soda (doh...)