galvanized metal stock tank
My tank is 5' diameter and 2' deep.
I initially painted it wiht black eposy paint which eventually flaked off -- no primer.
Then I pressurewashed it, couldn't get all the flakes off with scrubbing, so I bought an 8'x10' sheet of pond liner form JustLiners.com for ~$40 and glued it to make a cylinder to fit inside and fold over the top.
Were I to do it all over again, I'd just rinse the tank to remove manufacturing chemicals and use it plain. I wanted the black color for the looks of it, as the pond is in the courtyard and visible/audible from most of the house. I used 3" diameter fence posts to make fake bamboo and used metal pallet banding to strap it to the tank.
I use a fountain/sponge/filter/water pump for the fountain -- no spray just gushing water to about 4" tall, then have a pressure filter/UV and large pump inside the pond -- this was overkill and a huge pain to service. I'd suggest one or two air driven sponge filters instead. The UV leaked when the filter got too plugged up, hardly need it anyhow, any spring green water is controlled by reducing fish food and waiting for water temp to warm. Need a replacement sponge for inside the pressure filter and can't locate one - Anybody want to buy a used filter?