Yes, that seems to be yet another misconception about these plants! They actually do better in warmer temps and can tolerate cooler conditions, but when the photoperiod drops to less than 8 hrs, combined with the cooler temps, they will go dormant, and form turions; I doubt that they will go dormant in tropical conditions when the photoperiod is essentially the same all year long, and the temps are well above those that which may induce them to form turions.
The water temps in my ponds are very warm during the summer months, and is actually a problem in one site where the fish population is in decline. The Aldrovanda loves it! I actually have two sites, one in New Jersey, and one in New York.
As for the water quality, the site in New Jersey gets all the salts and chemicals from the parking lots and streets around the shopping mall, ice melting salts, gasoline, soap, oil slicks and all, and so long as there are loads of companion plants growing with them, (they actually take the hit, as their roots absorb these things), the Aldrovanda does just fine!
- Rich