FYI: Dry Ice

[Biscuit Oliva]

I see on this forum that many people have a problem with cooling their tanks. have an idea that may or may not work its more of an experiment.Im going to set up a small tank just basic stuff inside but under the tank im going to provide a leather sack filled with dry ice it's going to be well insulted so not to drop the temperature too much.Dry ice is cheap and i have it in abundance. The idea is similar to using an undertank heater for desert reptiles.Let me Know your opinions on this.

 

[Azhael]

I´m curious as to how this would work out. Can´t give any feedback, though, since i have no experience with dry ice.

 

[pete]

Just be careful not to suffocate your animals. I imagine if it was above the tank it could easily fill the tank with CO2. I know you plan on keeping it under it, but you never know what will happen. I'm sure you could do it safely, but I don't think I'd recommend it.

 

[Biscuit Oliva]

You are right pete, it is a little dangerous but so far it´s been okay. There are no animals inside, though, it's a little 10 gallon set up. I´ll be posting pictures soon. So far the tank´s okay it's actually at 60ºF but the pH has dropped to about 6.5 previously being at 7.4.I´m not sure if lower temperatures mean lower pH.

 

[Jennewt]

CO2 added to water causes the pH to decrease. I would guess that the pH shift you see is due to the CO2, not the temperature. According to this article, even the amount of pH produced by a home heating system can affect tank pH (although the change is so small I'm not sure I believe the data):
http://www.advancedaquarist.com/issues/apr2002/short.htm
Try stopping the dry ice for a few days and see if the pH goes back up.

 

[Abrahm]

CO2 added to water causes the pH to decrease. I would guess that the pH shift you see is due to the CO2, not the temperature. According to this article, even the amount of pH produced by a home heating system can affect tank pH (although the change is so small I'm not sure I believe the data):
http://www.advancedaquarist.com/issues/apr2002/short.htm
Try stopping the dry ice for a few days and see if the pH goes back up.

Yup, the CO2 gas from the dry ice is going to be a mild acid and lower the pH of your water.

There is one other concern I would have using dry ice and that would be the heavy, cold CO2 that sublimes from the dry ice could create a thin layer over the water that might lower the O2 in the aquarium. A hypoxic environment like that could lead to stress or even your animals asphyxiating.