Bacteria will grow in cold water down to 32 F. but much more slowly than warmer temps. Optimum temps are in the link I posted in this thread.

http://www.bioconlabs.com/nitribactfacts.html

Can't tell you which would be the best insulator. Perhaps someone else can. You will lose most of your heat from the top of your vessels so cover the tops in addition to the sides.

I know I'm repeating myself, but If you use ammonia for cycling be sure it doesn't sudz when you shake it. If it does that means it has detergent added and you don't want to use that. I got mine from Ace hardware.

I hope 800 watts is enough. I'm skeptical in your garage with your winter temps unless you build a frame and plastic and/or foam sheeting to isolate the system from the rest of the garage to create a microclimate.

And remember if you try and skimp on heater wattage you may end up using more energy as it will have to run more.

The heater in your link seems very cheap for a quality 500 watt heater. I see you can set the temp but I prefer one with an actual controller.

I use this one for all my school systems:

http://www.amazon.com/Catalina-RF-1000T-...aquarium+heater

Last edited by Cecil Baird1; 11/14/15 07:46 AM.
If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.