Gary:

If the tank is a goner for fish and the frame is still sound, if you just strip out all of the sealant inside the bottom, it will leak on it's own. Lay some stones on the bottom, cover them with screening and then the soil, and the chances are that you will lose excess water without any need for bailing, drilling holes or possibly even a cover.

Hi
Had thought of that but it would quickly turn the shadehouse into a mudhole. not to mention the wear on the stand.. When it was an aquarium I had a built in overflow
which overflowered into the garden via a hose.
Actually it would be nice if it would hold two/ three inches of water then I could use the aquarium heater as a heat source. Don't know of any heater for air that can take being wet not to mention how much room it would take up.
As to a lid I found glass too fragile unless 1/4 inch then it was too heavy lol. The necessary piece is so large. Plexiglass tended to discolor very quickly the cheap stuff would craze. Went with fiberglass screen with a vinyl frame but that won't keep water out of course.
There MUST be something I can do with it . It is so heavy even empty and must pass through two doorways to get it out of the shadehouse. My back hurts just thinking about moving it lol Thanks for the suggestions. gary

Okay, then check out off-brand masonry hole saws at your local HC. The cheapies won't hold up for many holes, but you only need one. Drill, insert a bulkhead fitting with a threaded connection to fit a standard garden hose and you will be good to go.

Hi
This is an "all glass " aquarium ,half inch thick. I have checked with a glass co and they told me I need a diamond drill.70 bucks for a half inch. If the glass is tempered it will most likely shatter without a drill press.
Have been experimenting with some PVC pipe which works great as a siphon but of course stops when it runs out of water. I seem to remember some kind of valve that will hold the pressure ,used in self cleaning cistern systems but don't know what to ask for . Maybe some type of air lift if I can size the pipes just right.?? Thanks for the help. gary

Gary,

What about a small submersable pump?

Presuming you will be creating drainage space under the planting soil and a screen of some type over the layer of stones or whatever you use to create the drainage space to prevent the soil from filling it, you could set a little fountain pump under the screening and just switch it on when you have a heavy rain.

Hi
Think I will go with a false bottom setup. That way it can be filtered ,heated and maybe a bit landscaped. The lid has me most perplexed if it keeps out the water will also keep in the heat. Being in direct sun ,going to get terrific heat buildup even in winter.Don't know of any kind of fan that will handle getting wet.
Think I'll do just a basic setup with materials I have on hand . No use in investing a lot of money in a 6 foot vegetable steamer.lol Thanks for the help!! gary