Unicel C-5315 first. Get a couple of them.
Consider also upgrading your filter/pump to a higher flow unit, possibly a sand filter. I'm finding my 633EG is just adequate -- as in is just enough pump/filter -- for my 15' Intex. I do however, have dogs that enjoy daily swims, which does affect the pool quite a bit. With a mudhole for a yard (working on it!) I get a lot of silt and dog hair in the pool.
With your larger pool, you would benefit from an upgrade.
Consider also upgrading your filter/pump to a higher flow unit, possibly a sand filter. I'm finding my 633EG is just adequate -- as in is just enough pump/filter -- for my 15' Intex. I do however, have dogs that enjoy daily swims, which does affect the pool quite a bit. With a mudhole for a yard (working on it!) I get a lot of silt and dog hair in the pool.
With your larger pool, you would benefit from an upgrade.
