Covering pond for the winter

[big ron]

I have decided to cover my pond ( 10'x 15' ) this winter with reinforced poly to help keep the leaves and debris out.  The pond is 3' deep and I will be running the pump through the waterfall as I did last year.  It will also have a heater in the pond.  I will have a 3'x3' access hole in the plastic to monitor what is happening throughout the winter.  My questions are :
Would it be better to remove the pump and install an aerator maybe with 2 outlets for oxegen or use both incase one fails ?     Also I have been told that the plastic cannot be air tight because you need to have a way for gases to escape.  Please advise as this is my first time covering my pond.     Thanks   

[tweetybaby2005]

Hi big ron, it is true that the pond should not be sealed air tight.  Gas exchange is important, especially if you have fish.  I use a net with 3/8" opening for my 16'x5' pond.  It takes care of most leaves and debris.  Not sure which zone you are in but if you are in the colder climate, instead of using heater, use the bubblers.  You can even turn off the pump since the 2 air stones will keep a nice hole open.  I use 2 air stones and the cheap fish tank air pump I bought from the Wally World for $20.  I've used it 3 years.  So far, fingers crossed - I have no fish loss. HTH.

Kuan

[minnowman]

Carbon dioxide can build up in a closed greenhouse which can cause the fish to become lethargic. An easy way to prevent this is to locate the air blower intake outside the greenhouse. Good luck.

[tranquility]

Carbon dioxide can build up in a closed greenhouse which can cause the fish to become lethargic. An easy way to prevent this is to locate the air blower intake outside the greenhouse. Good luck.

This is what I did-plus on nice sunny days I'd open one end of the plastic up so that they could get lots of fresh air in and so the pond wouldn't get tooo hot...even with out a heater if the sun is out a gh type structure like we build over our ponds can get HOT....In my gh it can be below 20 outside but, as long as the sun is out then the temps will get in the 80's and water holds heat so if you  live in a mild enough climate I'd suggest really watching those water temps if your using a heater it may get way too warm on nicer days.....
Lawanna