I didn't, but I can. I ended up breaking out my 1/10 HP chiller and have it running. They are horribly counterproductive as they require a pump in your reservoir (heat source) and they need to exhaust the heat dissipation (another heat source). I've considered running a satellite plumbing rig off of my existing RDWC pump, so as not to have a heat generating pump in my rez but, wow, just another job with cutting, gluing, plumbing, snake wrestling, etc...not to mention the down time on my plants while the PVC glue cures.
My chiller has brought the temps down from 78F to 73F. I know that dissolved oxygen is greatly lessened the closer you get to 80F, but with all of my reefing experience and growing high end SPS corals, along with the fact that the most healthy reefs (at least for now) in the world in Papua New Guinea and other parts of the coral triangle, all thrive in high 70s to mid 80s. This lets me know that there's still plenty of oxygen in the water at these temps (from tides, winds, etc). I, for one, believe that this can be applied to hydroponics with the right tools and methods in place. Products like Aquashield, Hydroguard, and Hygrozyme have been developed exactly for these conditions. Knock on wood, but I've never had a root rot problem, even with higher than optimal water temps using these products. With the incredible amount of circulation via the main rez pump, the jet heads (or air stones), and the introduction of fresh, external air with an airstone in the main rez, it's not too far fetched to think that the plants will do well and thrive. I've seen it many times before. Just consider that some outdoor, black smartpots hit 140 - 150F, or higher, when getting hit with direct, mid-summer sunlight and air temps in the 100s. Those roots, while maybe not ideal, still produce 6 - 10 LB plants.
All this being said, I added some Hydroguard today and hooked up the chiller. I normally wouldn't have taken these steps, but the foam kind of freaked me out because I've never seen it in my many years of DWC hydro. The optimist in me wants to say that it's the bennies in the organic Botanicare line I'm using (just like a tea foams), but who knows? I'm hoping I can eliminate the chiller....they suck (both power and figuratively).
Luckily, it's getting hot in my neck of the woods and I've specially ducted the AC into this room and it will be running more and more regularly in the coming days and weeks. I ran it today and it dropped the room temps drastically which, obviously, causes the water temp to drop with the ambient room temps being lower. And in the winter, it's very cool in this basement room. I like the challenge of tackling curve balls along the way in room setups.