Heat mats, how to calculate appropriate size mat for tank?

[Guest]

Hi, um, I think my subject pretty much says it all! Lol! How do I know what size mat I need for what size tank? I am looking into buying a new tank and will buy a new mat at the same time. Anyone got a good formula for working it out? I live in the UK so it's freeeeeeeeeeezing here so don't assume I'm as lucky as most of you guys and don't need much heat because it's sunny and hot outside! lol!xx

[Crabby Abby]

UTH's are said to warm your tank 5-10 degrees warmer than room temp. Bottom mounts require shall substrate, a 2-3" maximum depth which most of us don't use. Side mounts require a UtH 3x's the recommended size.Personally, while I now mount side only, even when I bottom mounted I never achieved a 10 degree increase. If your home is that drafty inside or you keep your thermostat set in the high 60s as some people do (brrrr) I'd say jump up one more size than the above instructions call for or side mount a 2nd smaller one (10-20g size) on the short tend of the tank, kitty corner to the first one.

[Nicole]

Substrate should be kept around 4-6", enough for tunneling and burying. For bottom-mounted UTHs, though, this could be too deep to penetrate and thus the tank will not get heated as much as it could (and should) be. Side-mounting on glass is fine, but do get a UTH that is rated for at least 3x the size of the tank that you currently have. For example, if you have a 10 gallon tank, get a UTH that is rated for a 30 gallon tank.If you still want to bottom-mount, you'll want to keep the substrate at a lower depth and make sure not to cover the entire bottom of the tank as the crabs need both a warm and a cooler area to choose from. Also, using a bottom-mount UTH requires special care with molters as turning it off and on could inadvertently cook a weak and resting molter. Be sure to keep your UTH on at all times if you have buried crabs.