Did you do the bucket test?

The CuLator products are distinguished by how much metal they can collect. If you have a LOT of metal (lots of colored sediment in the bucket test) OR if you are pretty sure you have metals in your FILL water, you might want to get the biggest one. If you do NOT have much colored sediment, and do NOT have metal in your fill water, then the smallest will probably work.

But . . . either way, you probably want to get skimmer socks, to protect the CuLater from gunk that could otherwise clog it, and render it useless.