we recently bought an older model mspa not sure how old or what model everything seems to be working fine except i have no idea where the filter is located, i looked up a manual but it wasnt much help as its for a new model maybe it didnt have one in it when we got it? there is something similar to what the manual shows on one of the intakes the inside of the spa it unscrews and comes off but doesnt look like a filter could go in it... anyone have one of these or know where its located? there is another larger intake but the cover for that doesnt seem to come off...