Best Pool Test Kit: Strips vs Drops vs Digital

No kit is "best" for every pool. The right one depends on how precise you need to be and how often you test. The CDC says home pool owners can use test strips, but that they "are less accurate than the DPD test kit." A pool that gets shocked, a salt pool, or any pool with a chlorine problem benefits from a drop kit. A small, steady pool can often get by with strips and an occasional drop test.

Strips, drops, and digital: how they compare

The table below lists what each type reads and how finely. All specs come from the maker's page or a trade source, listed under Sources. Where a number is missing, we say so.

Pool test kit types: what they measure and how precisely
Kit type	What it reads	Resolution	Where it goes wrong
Test strips	Usually free chlorine, pH, TA, hardness, and CYA, depending on the strip	Color steps on the bottle chart (see test strips)	Lighting, reader's eye, and old or damp strips. "You may not get the same result on repeated tests" (Pool & Spa News).
OTO or DPD color-block kit	Chlorine and pH, by matching a color to a block	Limited by the color blocks	OTO cannot tell free from total chlorine. Most DPD color blocks read chlorine up to 5 ppm. Between about 10–15 ppm the color can bleach and show zero.
FAS-DPD drop kit (Taylor K-2006)	Free and combined chlorine, pH, TA, calcium hardness, CYA, plus acid and base demand	Chlorine: 1 drop = 0.2 or 0.5 ppm. TA: 1 drop = 10 ppm. Calcium: 1 drop = 10 ppm. CYA: 30, 40, 50 up to 100 ppm. pH: 7.0, 7.2, 7.4, 7.6, 7.8, 8.0.	Takes a few minutes and a steady hand with the drops. Reagents expire.
FAS-DPD drop kit (TF-100)	Free chlorine, combined chlorine, pH, TA, calcium hardness, and CYA	Maker says combined chlorine reads down to 0.2 ppm and free chlorine reads precisely at high levels	We could not confirm per-drop figures for the other tests, or the reagent volume, on the maker's page.
Digital photometer (Hanna HI83326)	Free and total chlorine, pH, TA, CYA, and more	Free chlorine 0.01 mg/L over 0.00–5.00 mg/L, accuracy ±0.03 mg/L ±3%. pH 0.1, ±0.1. TA 1 mg/L, ±5 mg/L ±5%. CYA 1 mg/L, ±1 mg/L ±15%.	A professional instrument. Chlorine range stops at 5.00 mg/L. Needs correct reagent steps and a clean vial. We did not find specs for consumer-grade digital testers.

FAS-DPD stands for ferrous ammonium sulfate with DPD. The kit adds drops until the pink color turns clear, so you count drops instead of matching a color. It still reads when chlorine is high, and Taylor says a free chlorine reading from 0.2 to 20 ppm. That makes it the one to reach for after you shock.

If your strip and your drop kit disagree, trust the drop kit and check the strip bottle's date. The reasons are on how to read pool test strips.

Taylor K-2006 vs TF-100

Both are FAS-DPD kits for a home pool. Both read free and combined chlorine, pH, total alkalinity, calcium hardness, and CYA. The K-2006 adds acid demand and base demand tests, and Taylor sells related versions that add salt or read bromine. The TF-100 is made by TFTestKits, not by Taylor, and its maker states it reads combined chlorine down to 0.2 ppm. We could not confirm from either maker's page how many tests each kit gives per set of reagents, or differences in per-drop precision for pH and hardness. Compare the two product pages and look at the reagent size for your use. Whichever you pick, check the reagent dates. Reagents are the part that expires, and a kit with old reagents is worse than a fresh strip.

What does a test really cost?

Price per test is easier to figure than most people think:

cost per test = kit price ÷ number of tests the kit gives for that item

For a strip bottle, that is the price divided by the number of strips. For a drop kit, use the reagent refill price and the number of tests the maker lists. We did not copy any shop prices onto this page, since they change often. Use today's price and the count printed on the box. Count tests per item, not per box, because one kit may give a different count for chlorine than for CYA. A drop kit costs more at the start and often less per test than strips if you test often, but that depends on the numbers you use.

Which kit for which pool

Small inflatable or kiddie pool: strips are fine for a quick look. For very small pools, our advice (not a published rule) is to drain and refill rather than chase chemistry; see the kiddie pool chlorine page.
Above-ground pool with vinyl liner: strips for daily checks, and a drop kit once a week or after any shock. See above-ground pool care.
Plaster, pebble, or fiberglass: a drop kit with calcium hardness and CYA. These are the numbers that change slowly and cost the most to fix. See chemical levels by pool type.
Salt pool: you need a salt reading too. Taylor sells a version of the Complete kit with salt. Keep a drop kit for chlorine.
Hot tub: a kit that reads bromine if you use it, or a chlorine kit if you don't. A strip made for spas is fine for daily checks. See hot tub chemicals for beginners.
Shocking or algae treatment: a FAS-DPD drop kit. Color-block tests can bleach at high chlorine.

Are test kits accurate?

They are accurate for what they are built to do, within limits. A strip reads in steps, so it gives a range. A drop kit gives you a number with a resolution (such as 0.2 ppm per drop). A photometer gives a digital number, but the number is only as good as the sample, the reagents, and the calibration. Pool & Spa News notes that strip results depend on lighting and on the person reading them. Color-matching drop tests have the same weakness. So:

Test in good light, out of direct sun, with the pump running.
Take the sample about elbow deep, away from jets and skimmers.
Rinse the vials with sample water before each test.
Replace reagents by the date on the bottle.
Check a strip against a drop test now and then. If they disagree by more than one color step, trust the drops.

Whatever kit you choose, the numbers go into the pool chemical calculator to get a plan, and a few apps also read them; see pool chemistry apps compared. The targets to compare against are on the pool chemistry chart, and CYA has its own test method on how to test cyanuric acid.

FAQ

What is the best pool test kit for accuracy?

A FAS-DPD drop kit, such as the Taylor K-2006, because it counts drops instead of matching colors. Taylor lists chlorine at 0.2 or 0.5 ppm per drop, and trade sources say it reads up to 20 ppm. Strips are less precise, according to the CDC.

Are pool test strips or liquid kits better?

Liquid (drop) kits are more precise, especially for chlorine. Strips are faster and good for a daily check. Many owners use strips daily and a drop kit weekly.

What is the difference between the Taylor K-2006 and the TF-100?

Both are FAS-DPD kits that read chlorine, pH, TA, calcium hardness, and CYA. The K-2006 also has acid and base demand tests. We could not confirm the number of tests per kit or other differences on the makers' pages.

Are digital pool testers accurate?

A lab-grade photometer, such as the Hanna HI83326, lists free chlorine accuracy of ±0.03 mg/L ±3% over 0.00–5.00 mg/L. We did not find specs for consumer-grade testers, so confirm one against a drop kit before you trust it.

Which test kit do I need for CYA?

The K-2006 and similar kits include a CYA test that reads 30–100 ppm in steps of 10 ppm. Strips read CYA in wide steps. Details are on the CYA testing page.

Sources

CDC, Home pool and hot tub water treatment and testing (DPD kit vs strips): cdc.gov
Taylor Technologies, Complete Test Kit FAS-DPD (K-2006) product page (tests, per-drop sensitivity, CYA 30–100): taylortechnologies.com. Specs for this page were read from the search extract of Taylor's page, because the page itself was rate-limited when we fetched it. Re-check before you buy.
Taylor Technologies, Complete Test Kit with Salt (FAS-DPD): taylortechnologies.com
TFTestKits, TF-100 test kit (maker's page): tftestkits.com. Same note: details taken from a search extract.
Hanna Instruments, HI83326 pool and spa photometer (ranges, resolution, accuracy): hannainst.com
Pool & Spa News, Methods and limitations of routine pool water testing (DPD color blocks to 5 ppm, bleaching at 10–15 ppm, OTO, strips, FAS-DPD to 20 ppm): poolspanews.com