I know this thread is almost a year old, but I've been thinking about doing this this summer. Is it easiest to run a sponge filter for something like this or is a pond filter better? Also, I'm rural, I know raccoons and opossums are likely to be a problem. Along with birds, foxes, and maybe the coyotes. What's the best way to protect as well as you can from some critter deciding it's easy picking? What are reasonable time frames for keeping them out? Assuming mid April though early/mid September maybe? Thanks for any thoughts.
I have used Memorial Day to Labor Day as a guide. I watch for night time temperatures to get in the 60's before putting fish out. Night time temperatures are the main thing I watch for putting fish out and bringing them in. I set the tubs up a couple weeks ahead so they can cycle. or in my case I just use my pond water and hornwort that has wintered over in one of my 150 gallon tubs. I try and get some other plants out too. water Hyacinths and water lettuce. As to filtering. I have done nothing to running an airstone. A small pond pump would work too. The 110 tub are steep enough that I haven't had any trouble with varmints. I had a 40 gallon tubs out that attracted a fisher critter. I suspect it was a raccoon. I tried putting a window screen over the top, but they moved it. I have put old shower doors on the tubs to extend the season. If you choose some fish that tolerate the cooler temperatures you can set them out earlier. If blue Heron's are a problem., you can string fishing line over the tubs. I put fishing line over my koi pond. (900 gallon stock tank)