resivor heat issues related to root rot?

Well, its been a while since i have visited RIU. I need some help (again). I had a terrible harvest this last time, somewhere in the neighborhood of 10 oz, (vs 26 oz) off my last harvest. What i have changed is the way i am adding C02. I am using a generator, instead of bottled co2. Here are the basics of my grow setup.
I have a 8x8 room lined with white non toxic 1" foam and tyveck tape at every seam. This is to control sound, and assure that i have no leakage so i can precisly control air pressure. The room is inside a larger room that is 12x18. this larger room houses my co2 generator, my nutes, supplies, my mother tent, my clone tent ect. I have my can fan carbon in my grow room exausting out into the larger room with make up air coming in from the larger room. The idea is the larger room acts as a heat sink allowing me to control temp better. ok, enough about that, so the problem i am having is a major dose of root rot. I believe it is due to the heat of the water in the rainforest modules. I keep the temp about 88* in the daytime to utilize the co2 most effectivly. However, over time, this raises the rainforest temp from a cool 73* up to 84* during the day cycle. So i have a peak 88* air temp, and a peak 84* water temp. This is way way to high. My plants basicly died at week 8 with no growth for the last two weeks. The root rot was as bad as i have ever seen. Most of the fan leaves dried up and fell of. The cola leaves to yellow, wilted, dried up and fell off.
So my questions:
Those of you who have your resivor in your grow room, how do you keep the resivor temps in the low 70*s?
Do you think that heat was the major cause of this problem?
FWIW, i have ordered a 1/10 horse chiller so i can eliminate resivor temp swings and isolate this problem further. I hope it fixes it. The amount of electricity and advanced nutes it took to grow this pathetic harvest puts it in the relm of epic fail.
If you guys would like to see my current set up i can post photos.

Also, i data log all my parameters with a microprocesser. If you have any specific questions about PH, temp at any given time of day i have logs that do data points every 10 minutes all day everyday.

THanks in advance for your help.

MountainHigh said:

Do you think that heat was the major cause of this problem?

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I've never grown hydroponically but have followed grow files of a few done that way. You have to have a chiller to prevent root rot. Without healthy roots your grow will suffer big time.

yes dude you want those roots cold and happy. around 65-67 is perfect if you can get it. remember no roots no fruits.

I have a smaller fan at the very bottom of the grow room realy just to keep tabs on the heat exspelled to the resiviour.and then my normal large fan inbetween the light and the plants.by haveing a fan at groun level this bring the temp down then the exaust fan pulls all the used air into the loft area into a carbon filter.i have no order issues and lucky for me i realy would'nt need a carbon filter every f@cker on the road smokes the shit so it always smells weedy avenue.

Thanks for the replies. I cant wait until i get the chiller next week. My last harvest was steller, right at 7oz/plant. This go round was almost a total failure, with a carbon copy plan from the last harvest. The only thing that is different this time from last is the root temps. Right now im holding root temps at 71* during the afternoons when its warm out, and 69* at night when the lights are out. once i get the chiller i can turn my co2 generator back on