I've a plastic water storage tank as such with a small lid (12"/30cm in diameter).
It has developed a thin slippery/shiny layer inside of the walls overtime and surface of the water has the same texture.
This tank, as far as I can remember, does not have a drain near the bottom.
My question is,
- what is that sticky film/material?
- how to get that sticky film/material off the walls and base?
- after (2), How to drain all of the water completely and easily, without moving the tank?