dont bother m8 get a liner
seriously you’ll regret it, unless you can keep perfect conditions and a constant temperature it is always prone to flake or peel
moisture will cause it to flake off or peel and also temperature fluctuations, alot of paint needs to be put on at a certain temp and also needs to be maintained by a certain temp in the pond or you will always have trouble with it flakeing /peeling
Fully enclosed 1800g pond, window, aireated bd to ultra sieve and 20,000 straight to shower, widemouth skimmer to static k1 chamber to 18000 straight to shower, submersible uv, shower with 80kg bhm and 2 x 4″ mid level returns