wow I'm doing the same thing but slowly this time we made a 60 gallon pond and it has now risen from the rain and the pump has burned out and it is a true mess so we went up to a 140 gallon pond which is a above ground now we haven't made it yet like I said slowly- but we are putting in a waterfall up higher than the pond and more of a flat surface for my turtle so she can sun more than just on the log and no food will go in pond - my fish are huge now so they go- only small ones to eat bugs she wont eat fish it was such a pain in such a small area it stunk and if you don't put light down in the water you can never see any thing except the rare times they come out as we know that's why there called sliders lol so I suggest make it bigger go to a really good pond or fish store that sells pond stuff like Ocean Floor- get a good filter system they can help it will cost you about four hundred dollars for filter and pump you can look on line cheaper-good luck and try to go bigger!!! IT is hard I know and expensive but the filtration system will last for years it has been tested try LAGUNA at www.lagunaponds.com best of luck my pond friend try looking on line there are many above, container and in ground ponds to see and directions-and a heater yes I live in az and use one only when its is cold she says out all year does fine get it at pet smart make sure you cage it they will chew and bump it good luck
