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That one will work but it is a 50SQ FT filter and I suggest going with a 35SQ Ft. You will have better water flow and the spa will still filter as good. Get the 5CH-352.
Assuming the same filter media, I would expect that the larger the area, the better the water flow - more pores for the water to get through. All things being equal, if a larger filter fits, it should also go longer before needing cleaning.
Reality is when filters are the same size and they put more pleats in i.e. 35 sq ft vs. 50 sq ft. they just make it tighter. It makes for less flow and harder to clean.
Nicksd,Why not go into yor dealer and get the correct replacement filter. Then you know you are getting the right one and not some cheap nock-off. If its price, how much are you really saving?
Are you implying that Unicel filters are cheap knock-offs? :-?
Why not go into your dealer and get the correct replacement filter.