Search:

The sand is most likely compacted then. If backwashing does not help, you will need to either exchange the sand for new or try to break up the sand chunks in the bottom of the filter(not recommended...

IF there is one spot of rust coming through it sounds like there is some rebar close to the shell surface. We used to have to chip out the metal and patch the spot. If it is just an imperfection in...

Many times there will be fertilizer marks forming along the sides and edges. Specifically where granules would drop and lay until dissolved. They contain high iron and would rust.

You do not need gravel, just the proper sand grain size.

I would first check the filter. Many times a clogged filter will cause cavitation and subsequent air discharge through the jets.