Ok here's my two cents on the filter washing....I broke down and bought another set (my prefilters come in sets of 2) of prefilters, and another big filter. Now, what we do is switch them out once a week or so..the dirty filter goes with my husband to his work where on his lunch he takes it to the back and uses the pressure washer to clean it...of course being ever mindful that it is fragile ( is this an itallian word? hehehe) The clean filter stays in the hot tub until it's time to swap the two.
There you have it! BTW....we have now gotten into a routine where the water in the hot tub gets changed about every 4-6 weeks depending on how much I use it!
BP