HardLuck

I just purchased an older Cal Spa and found that the filter bypass valve is broken, thus I am getting very poor filtration as the water is just bypassing the filter. I was told that it is a good idea to just replace the whole housing, rather than try to fix. Is this true? Also it is a top load suction filter system and was wondering if it is better to just switch to a pressure system and install a canister filter in the cabinet. Thanks