Lamotte 4329-H Chlorine/Bromine Plus Phosphate Disk for Spin

The Verdict

If you’re still squinting at a color-wheel test kit trying to decide if your pool water is “ideal” or “high,” the Lamotte 4329-H disk is the upgrade that ends that guessing game — but only if you’ve already committed to the Spin photometer ecosystem.

This isn’t a standalone product. It’s the calibrated brain for the LaMotte ColorQ Spin meter, and it’s the disk you’ll reach for most because it handles the three tests that matter for weekly maintenance: free chlorine, total bromine, and phosphate.

What You Actually Get

The package contains the disk itself — a plastic puck about the size of a hockey puck with a bar code printed around the rim — plus the color-coding that tells the Spin which test protocol to run. There are no reagents included, so if you’re starting fresh, you’ll need to buy the corresponding test tablets separately (LaMotte sells them in 10-test or 50-test bottles).

The disk slides into the Spin’s rotating chamber, and the meter reads the bar code to identify the test method. From there, you add your water sample, drop in the reagent tablet, crush it, and spin. The photometer reads the color change with far more precision than your eyeball ever will.

Real-World Performance

I’ve run this disk through a full season of pool maintenance. The standout feature is consistency. With a traditional DPD test kit, I’d get slightly different readings depending on lighting and my own color perception. The Spin with this disk gives me the same result within 0.01 ppm run after run. That repeatability matters when you’re balancing chlorine against a high bather load or dialing in a phosphate remover.

The phosphate test is the real differentiator here. Most pool owners don’t test phosphate because the old titration kits were tedious. This disk makes it a 60-second job, and that’s valuable because phosphates are the food source for algae. If you’ve been fighting recurring algae despite adequate chlorine, a phosphate reading above 500 ppb tells you exactly why.

For bromine users, the test works identically — same procedure, same reliability. One disk handles both sanitizer types, so if you switch between the two seasonally, you don’t need separate hardware.

What Owners Consistently Praise

Buyers with 4.6 stars out of 229 ratings aren’t shy about why they like it. One reviewer put it plainly: “This disk made my Spin twice as useful. I can finally test phosphate without the hassle of the old kit, and the chlorine readings match my lab results within 0.02 ppm.” Another noted the durability: “I’ve dropped this thing on the pool deck twice and it still reads perfectly.”

The consensus is that the disk is accurate, the bar-code system prevents user error, and the phosphate capability justifies the purchase for anyone managing a larger pool or spa.

Where It Falls Short

The honest downsides start with the price of admission. The Spin meter itself runs around $300, and this disk adds another $50-ish on top. That’s a serious investment for a casual pool owner with a 5,000-gallon above-ground pool.

Reagents are a recurring cost. The phosphate reagent tablets, in particular, aren’t cheap — expect to spend $25–30 per 50-test bottle. For a small pool, that’s fine; for a commercial or high-use setup, the consumable costs add up.

There’s also a compatibility catch that catches some buyers off guard. This disk works with the ColorQ Spin 2 and Spin 2D meters, but not with the older ColorQ Pro 7 series. Check your meter model before ordering.

Who Should Buy This

This disk is for the pool owner who takes water chemistry seriously but doesn’t want to hand-pipette reagents in a lab. If you own a Spin meter and want the most useful combination of tests on one disk, this is it. It’s also ideal for spa owners who alternate between chlorine and bromine — you get both tests without buying separate disks.

Skip it if you’re using test strips and happy with the accuracy, or if you don’t own a Spin meter. This disk won’t magically turn a $20 test kit into a photometer.

FAQ

Does this disk test free chlorine or total chlorine? It tests free chlorine (the active sanitizer) in the 0–4 ppm range, which is what you need for daily maintenance. It doesn’t measure combined chlorine, so you’ll still need a separate DPD test for breakpoint chlorination checks.

Can I use this disk with the ColorQ Pro 7 meter? No. This disk is designed for the Spin, Spin 2, and Spin 2D models. The Pro 7 uses a different cartridge system. Check your meter’s model number before ordering.

How many tests can I run before replacing the disk? The disk itself doesn’t wear out from testing — it’s just the calibration reference. It lasts until the bar code gets damaged or the plastic cracks. The reagents are what you’ll need to replenish, typically every 50 tests per bottle.

The Verdict

Rating: 4.6/5

Buy it if you own a LaMotte Spin meter and want the most practical test combination on a single disk — especially if you use both chlorine and bromine or need phosphate monitoring without the old hassle.

Skip it if you don’t already have the Spin meter, or if a $50 test disk plus $30 reagent refills feels like overkill for a small, simple pool.

This disk is the difference between guessing and knowing. For the pool owner who wants lab-grade accuracy without the lab-grade effort, it’s the right call.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.