Test strips or a drop kit for hot tub water?

Short answer

Either works, but CDC calls test strips less accurate than a DPD drop kit. Use strips for quick checks a few times a week and a kit when a reading looks wrong.

Updated October 2026By the HotTubFinder research desk

Reading a test strip: dip it, then match each pad to the chart on the bottle; free chlorine 3 ppm or more, pH 7.0 to 7.8, alkalinity in the range your manual gives — A test strip and the good range for each pad.

Hands holding a test strip up to the colour chart on its bottle beside a filled hot tub — Master Spas

Test strips and drop kits compared, from CDC and Master Spas
	Test strips	Drop (DPD) kit
How it works	Dip a strip, match pad colors to the chart	Fill a vial, add drops, match the color
Accuracy	Less accurate (CDC)	CDC's recommended method
Care	Moisture ruins them; reseal at once	Follow the kit's fill line and drop count
What it reads	Most read sanitizer, pH and alkalinity	Depends on the kit; can cover all five

Are hot tub test strips accurate enough?

For routine checks, yes; for decisions, back them up. CDC says owners can use strips but that they are less accurate than a DPD kit, the drop test it recommends. Master Spas' schedule uses strips three times a week, which is the job they suit: quick, cheap, good at spotting drift.

How do you read a hot tub test strip?

Shake one strip into your hand without touching the others, and seal the bottle straight away.
Dip it for as long as the bottle says.
Match each pad to the color key on the bottle within the time it gives.
Adjust in the maker's order: alkalinity, then pH, then sanitizer.

Some sanitizing systems come with their own strips. Bullfrog's says to use the strips supplied with its cartridge system, because they read the system's chlorine reserve.

What should you test in hot tub water?

Sanitizer and pH every time; alkalinity on most tests; calcium hardness at each fill and now and then after. Our hot tub water chemistry page lists each maker's ranges.