How can i stop my glass aquarium lids fogging up?

Question

1 tank is tropical 24-26c

1 tank is cold water 115c (axolotl)

Answer 1

That's a tough one...  While I know of several ways to keep glass from fogging, I'm pretty sure none of the solutions would be very beneficial in aquarium applications due to chemicals in the solvents used (WD-40 or commercial scuba lens defogger).

About the best thing I can suggest is to try keeping the water level up high enough to actually touch the glass lid.  This could lead to problems with oxygen absorption, so I would recommend increasing the amount of artificial aeration to make up the difference.

*EDIT*  DO NOT use any kind of oil anywhere on the inside of your aquarium!  Even a few drops of oil in an aquarium can spread out over the surface of the water, effectively ending the absorption of oxygen into the water.  Many oils can coat eyes and gills as fish feed at the surface; in the best case this may only be a minor irritant, worst case it will kill everything in your tank.

Answer 2

make the water room temp. ...!

Answer 3

They're going to get foggy - even if you don't heat the water with a heater, just having the light on over the water will heat it up a little and the evaporation of the water will fog the glass tops.

It doesn't hurt anything - is there a reason why you don't want your glass tops to fog up? One way people get around it is to have open-top tanks - usually with support legs holding up the lights on the sides of the tank. The fish shouldn't jump out unless your water is bad. Something to consider if you really want to see clear down into your tank.

Answer 4

Is the water temp higher than the outside air where the tank is located?  There is something you can buy to stop the fogging.

They put in on windshields so try the store where you can buy the anti fog  liquid and that should help you.

Answer 5

Just a theory:

I use oil on my glass pots & pans lids to keep them from fogging.

Melafix has Tea Tree Oil, and would not harm your tank. Maybe wipe down the cover with that? The worst that could happen is it would keep fogging.