eyoung, we went with a Hayward Pro Series, S220T Sand Filter because it is easier to clean and backwash. I am not sure that I will see a difference in water clarity with DE, then again I do not have any experience with DE. All I can say it is very easy to clean our filter and I usually do it when the pool is very full after a good rain. Our pressure runs about 18psi and we have 2 inch plumbing and a 1.5 hp pump with 4 water features, SWG, heat pump, pool size is 6k running pump 2hrs daily. Look at our thread "Our New Pool Build in Jacksonville, FL" Hope this helps.

I dont really have an opinion on differences between the 2 filtersyou mentioned, but I think you should reconsider the oversized filters. One,with 500+ feet of filter area you wont have to clean the filter as often, in fact on most pools I only do this every 6 mos. Second, the cartride on the small filter usually needs to be replaced every year while the big filters need new carts. typically every 4-5 years so the cost is the same. If you dont want to spend all that money at once, buy 1 cart a month.

Last summer, when I was thinking about getting a second set of cartridges to allow me to take my time cleaning them, I found Best Buy Pool Supply to have the best price that I could find on the net, about $277 total for both elements (told you they were pricey!). Top Dog Pool Supply came in at just over $350 and Pool Pump and Filter Superstore came in at the highest...nearly $390. I did not check eBay. After seeing those prices, I nixed the idea of having a second set for convenience. Not every site had my filter's elements, so there may be other sites with better pricing on yours. I've heard that some cartridge filters have generic filter elements that are much cheaper to replace but I haven't a clue as to how well they perform. Perhaps a PB could offer an opinion here...

First, are these two filters of equivalent size (not actual size)? Generally, a 60 sq-ft DE filter has about the same capacity as a 400 sq-ft cartridge. I know that sometimes the pressure loss does not depend on the filter size so maybe it doesn't matter. If they are comparable in size, then the difference would only be about 10 watts to get to 30 GPM (925 RPM vs 990 RPM). These of course are estimates only and your results may vary. BTW, I have a 420 sq-ft cartrdige filter on a 20k gallon pool and while they are a bit of a pain to clean, I only clean mine every 6 months (no closing) so it isn't so bad. It takes less than an hour to clean the four cartridges. Also, our city requires separation tanks on sand and DE filters which is why I ended going with a cartridge filter. I personally don't have a lot of experience with DE filters but many on this forum and other forums have. One reoccuring theme is that the grids on DE filter occasionally get clogged and require cleaning. From what I understand, this can be a messy job and not too unlike cleaning a cartridge filter. Also, after every backwashing, they require more DE. My point is that DE filters may or may not require less maintenance than a cartridge. No filter is perfect and each has pro and cons. You basically have to pick your poison. Also, what ever type of filter you choose, I would suggest that it is over sized so you don't have to clean it so often and so it cleans better.