Not all plastic tanks are acid safe so check the codes for HDPEhttp://www3.sympatico.ca/n.rieck/docs/plastic_codes.HTML
Then TEST a small spot.
Better yet a hard scale or lime remover like CLR may work better and dissolve faster.
A strong Vinegar or a weak Sulphuric Acid solution would also be better than a HCL solution for fish.
Most fish are very pH sensitive so rinse very well...
No. Muriatic acid will not remove paint from concrete. Muriatic acid will etch bare concrete though.
It will remove pigeon feces
I think it might remove rust AND pipes. Be careful with that stuff.
You can remove mineral deposits from your teapot with a mild vinegar solution.
Because the muriatic acid will eat everything else up too, including your pipe!!!
Drain pool and clean with muriatic acid
Shouldnt think so.Best way is to sandblast
muriatic acid should work fairly well
Use diluted muriatic acid and a scrub brush to remove efflorescence. Neutralize with water or ammonia.
Boil them in vinegar.