Another filter looks like it will fit my hot tub, will it work?
In many cases a filter which is 5 to 10mm bigger, either in height or diameter will fit into the receiver of your hot tub, and many people choose to do this, either because their own filter is difficult to source or has gone out of production, or because it offers a significant cost saving.
The first consideration is usually the 'top' of the cartridge. If your filter cartridge has a closed top, then you cannot use a cartridge with a hole in it, as water will simply go down the hole and bypass the cartridge. If the top is identical looking and the bottom thread is also identical, then providing the square footage of the cartridge is within ten to fifteen percent of your original (and it fits in your spa) then it is unlikely to have any detrimental affect.
Warning: It is possible to starve pumps of water or cause them to work unnecessarily hard by using filters which are significantly out of specification and this may cause damage to your hot tub.