Quote Originally Posted by Poconos View Post
Sounds like the match would work just fine. One question though....why the switch? Sand is the easiest to maintain and if you want to filter out finer stuff then you can throw some DE powder in it. Cartridges have a high recurring cost.
Al
The reason i'm considering a switch is because i'm retired and have the time to clean the cartridge. For the working people, go with the sand filter. In my 25 years i've only replaced the sand once and never had any parts to go bad. Now, taken the sand out of the filter, adding more and replacing all the fittings is a job this old man doesn't want in my golden years.

Quote Originally Posted by CarlD View Post
25 years? It doesn't owe you a dime! Unless you've figured out the tricks for cleaning a cartridge with minimal pain you will find yourself cursing the day you got it.
Don't get me wrong: A cartridge system can be very successful. Those who master the cleaning tricks love them. Those who don't, hate them.
It's like eating Maryland steamed spiced crabs. They are an immense amount of work to eat unless someone shows you the trick for eating them. Then they are easy to eat. But the trick is totally NON-intuitive.
Lucky for me, i've lived around the ocean all my life and know how to clean a Maryland steamed crab. Seriously, the worst thing that could happen is i hate it, and there went $250 down the drain. Might be able to sell it on craigslist for half price or below. The cartridge type filters are initially cheaper than sand filters by about a hundred bucks, and if i only have to replace the cartridge every 4-5 years @ $60 bucks, that would be very affordable. I've read that cartridge filters work well with chorine and that's all i use with the exception of some PH plus. Haven't made a final decision yet.

Quote Originally Posted by polyvue View Post
Well, somebody has to stick up for cartridge filters...
The return flow should be unaffected by the changeover to a cartridge filter but it does seem the model you chose is a bit on the small side for a 18x36' 30K gallon pool. Maintenance can be a chore if you're having to disassemble the thing every month to clean the filter. That was the principle motivation when I selected an oversized cartridge filter (see equipment in my signature line) for my pool.
The C-751 provides about 75 sq ft of filter media for your ~650 sq ft pool. The SwimClear C4025 on my system provides 425 sq ft of filter media (and has twice the flow capacity), yet my pool is about half the size of yours.
You see where I'm going with this. I clean the filter once a year and even then it's not really dirty.
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Point well taken, but anything over 90 gpm they recommend 2" plumbing and mine is 1 1/2" and all the return lines are in cement. I might go to the next size up, but that raises the price of the filter by $10 bucks but might be worth it. Just found a cool calculator (link below) that will give you an estimate of the total gallons of water in pool. If i go with the cartridge filter, i will run a shutoff valve going to the filter and a tee going to the waste line with another shutoff valve. My waste line runs to the storm gutters at the street, so can dump all 30,000 gallons if need be. Hopefully another year will pass without a hurricane, but keep a cover handy in case. BTW, i cannot see your signature. Must have something to do with newbie's permission and privileges. I need to take the time and read the site rules i guess.

http://www.royalswimmingpools.com/Gallon_Calculator.htm