DE Grids vs Cartridges: The Arizona Pool Owner's End-of-Season Parts Guide (FS-2006, C-7447, SS10100)

On January 1, 1960, Del Webb opened Sun City northwest of Phoenix and something like a hundred thousand people showed up over the opening weekend — enough to jam the roads for miles. What they had come to see was a new idea about how to live in the desert, and the centerpiece of the sales pitch was water: a swimming pool, in your community, in the middle of the Sonoran Desert, usable in February. Arizona has never really gotten over it. Around metro Phoenix a backyard pool reads less like a luxury and more like standard equipment.

Sun City, Arizona — the desert community that sold America on the backyard pool (photo: Wikimedia Commons).

What nobody puts on the brochure is that a desert pool is a filtration problem. Monsoon dust, palo verde litter, blowing sand, 110-degree water that grows algae like a science experiment, and a filter running long hours a day to keep up. September — right as the season winds down and the dust settles out — is when the parts bill comes due.

Your filter is one of three types. Know which.

DE (diatomaceous earth) filters the finest of the three — down into the few-micron range — which is why DE pools look glassy. Inside is a set of fabric-covered grids you coat with DE powder after every backwash. Cartridge filters use pleated media, no backwash, and you hose them off. Sand is the coarsest and the most forgiving. Desert pools with heavy dust loads tend to do best on DE or a generously oversized cartridge.

When DE grids are actually finished

Grids do not last forever, and the tells are specific: DE powder blowing back into the pool through the returns after you recharge, a pressure gauge that climbs back to dirty within days of a clean, visible tears or thin worn patches in the fabric, or grids that have gone stiff and cardboard-like. Once one grid tears, the rest are the same age — replace the set, not the piece.

We have a 72 sq ft DE grid set, 7 full grids plus 1 partial, for $179.99 that covers the Hayward-compatible FS-2006 / FC-9560 / PFS3672 / DEX7200DA pattern — the 72 sq ft size used on a lot of residential inground systems. Buy the whole set; mixing new grids with old ones just channels flow around the new fabric.

When a cartridge is worth cleaning — and when it isn't

Rinse a cartridge when the pressure gauge rises about 8–10 psi over its clean baseline. Soak it overnight in a filter cleaner a couple of times a season to pull out the sunscreen oils and mineral scale a garden hose leaves behind. Replace it when the pleats stay grey after soaking, when the end caps separate, or when the bands crack. Rough rule: two to three seasons of hard desert duty.

Our Cryspool 07034 four-pack at $74.95 is the C-7447 / PA50SV 50 sq ft pattern for Hayward SwimClear C2020 systems — four 14-inch cartridges, which is a complete set for that housing rather than a single. Keeping a spare set is the trick: swap them, then clean the dirty set at your leisure instead of running the pool dirty for a day.

The light nobody replaces until it's dark

Old incandescent pool lights draw 300–500 watts and burn out on a schedule. An LED replacement pulls a fraction of that and lasts years longer, which is why this is one of the few pool upgrades that pays for itself. We have a 10-inch RGB LED inground light, model SS10100, at $134.95 — 316 stainless housing for the wet niche and a 50-foot cord, which matters more than people expect: the cord has to reach the junction box without a splice.

Do this one right. Kill the breaker, and if you are not certain about the bonding and GFCI side of the job, have an electrician land it. Pool wiring is the one place in the yard where cutting a corner is genuinely dangerous.

Spas and closing up

Running a salt system on a spa? A two-pack of Hot Spring–compatible salt system cartridges at $142.99 is a season's worth — these are consumables, and a spent cell quietly stops sanitizing long before anything looks wrong.

For above-ground pools that get closed, a winter cover keeps the leaf load and the algae bloom out of water you will otherwise be shocking in March. We stock a 24 ft round winter cover at $95.99 (9 in stock) and a 21 ft round at $95.99. Measure the pool itself, not the old cover — covers are sized with overlap built in.