How much non-chlorine shock for your hot tub, by size

Non-chlorine shock (potassium monopersulfate, MPS), the routine oxidizer for hot tubs. Pick your tub size for a full table, or use the calculator for any volume.

Pick your tub size

Tub size	Dose
200 gallons (757 L)	1.5 oz per dose
250 gallons (946 L)	1.9 oz per dose
300 gallons (1,136 L)	2.2 oz per dose
350 gallons (1,325 L)	2.6 oz per dose
400 gallons (1,514 L)	3 oz per dose
500 gallons (1,893 L)	3.8 oz per dose

Any other size

Add

3oz

of Non-chlorine shock (MPS 45%)

85 gabout 4 tbsp by volume

The routine label dose for 400 gal: once a week, and after a heavy soak.

Side effects: TA −12 ppm.
MPS reads as combined chlorine on DPD tests for about a day. Test CC the next morning.
Run the jets with the lid open and wait at least 15 minutes (20 after pH decreaser) before anyone gets in.
MPS shows up as combined chlorine on DPD tests for about a day.
MPS burns off what soakers leave behind but does not sanitize. Keep chlorine in range as well.
Leave the cover open for at least 15 minutes with the jets running.

Check the product label. Strengths vary by brand, so enter the % printed on yours. Add one chemical at a time, into the water, and never mix chemicals.

Save this test and get a reminder before your next soak.

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How much non-chlorine shock for your hot tub, by size

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