+1 for this. I bought 4 x 55g food grade drums on offer up for about $60 for all. Quick questions, is the air stone a must? I have a pump in there just circulating water and you can see ripples on the surface.
A nice little tip:
I like to make things easy for me so I got a toilet lever and installed it to my drum. I connected the water hose (from the house, could be well) into the other end and it auto tops off when the sprinkler system kicks on. I also do my water changes in the afternoon right before sunset since the water is nice and warm despite having two heaters in the drum.
I almost got Killed for this, but I drilled 2 x 1 in. hole through the wall behind my tank and I ran a hose through and attached it to my tank. With the tap of a button, it refills my tank. I do not have a drain built in yet. I siphon the water out through my window and I have to be present to stop the pump before it overfills. The idea is to put a bulk head on the sump and have it drain out through the second hole.