I clean my cartridge every month, but it really hasn't been that bad yet(BBB user). I don't think I'd be in much of a hurry to spend the money on a new cartridge until you convert. Why ruin a new cartridge if it's only going to need to be replaced when you decide to convert.

With the problems and troubles that it sounds like your devolping...I wonder if it would be less work (for the remainder of the year) to just convert now.

happy swimmin',
dan