I use Leisure times filter clean product and have had decent luck with it.
I have an extra filter and when it comes time to clean the filter, I swap in the clean one and soak the dirty filter in a
5 gallon bucket that I add the filter clean and water to, and let the filter soak for 24 hrs. It comes out clean as a whistle. I snap a cover on the bucket and save the cleaner solution for next time (it can be resues about 3 times or so).
I rinse the filter excessivley with a hand held shower sprayer, making sure to get in between all the pleats.
The cleaner is very caustic. When I first used it I mixed too much of it, and had my hands in the solution agitating it. within an hour the skin on hands was peeling off. I wear gloves now when handling that stuff and make sure I add only the appropriate amount.
Nasty stuff, but works well.
I have also used a purple spray on cleaner (spray it directly on the filter and let is stand for a few minutes and rinse). It worked ok, but I prefer soaking the filter overnight in a solution. It's easier and comes out cleaner, imho.