Quote Originally Posted by foodchain
Why track them? Tracking them provides you data on trends and cycles. If you are using a heater in the water, the thermostat there maintains a more or less constant temp. If you are doing this outside, as in my case...you are relying on the weather. In which case you utilize the appropriate species of plants, fish accordingly. Don't get me wrong. Data is important in a lot of things. But documenting water temp trends, especially in a heated system....just doesn't make sense to me.

I am not trying to be insulting or patronizing. I legitametly don't understand this. You are relying on a purchased thermostat to keep that temp. So depending on your water volume, you really aren't going to see much of a swing in degrees the greater the volume, the more stable it is. Which from either a fish or plant stand point, is more than tolerable, if not desirable.

Perhaps I am just proving my own ignorance.
Not true that part about constant temp! Not at all!

My systems are all outdoor systems. I have one system heated with immersion heaters, one system heated via a greenhouse tent, and one system unheated. In the past 24 hours, my heated system has gone from a high of 78F to a low of 68F. My greenhouse system has gone from a high of 76F to a low of 67F. My unheated system has gone from a high of 79F to a low of 49F. Ambient temps in the past 24 hours have ranged from 85F to 46F. Why track? Well, because I need to know each systems response to swings in ambient temperatures. The water temp can affect the capacity of the bacteria to do their nitrification thing and the water temps can affect the survivability of my tilapia. I need to track how much warmer than ambient temps my water stays so as to adjust feeding rates and to know when to apply drastic warming measures when the occasional cold snap hits. Even here in south Florida, we have the occasional (rare, but not unheard of) morning frost. If I track temp data, I can easily compute each systems likely low water temp based on the forecast ambient lows and take appropriate precautionary measure if needed.