We may earn a commission when you buy through links on this page, at no extra cost to you. As an Amazon Associate we earn from qualifying purchases.
For most hot tubs, the best hot tub shock is a non-chlorine one, and Leisure Time Renew is our top pick.
It works with chlorine and bromine, you can soak again after 15 minutes, and it has the biggest rating pool of the oxygen shocks we looked at.
If you want the fewest refills, SpaGuard Spa Shock goes furthest per container at the weekly dose.
Here’s the catch the product pages don’t spell out… every brand writes its dose for a different number of gallons.
So we scaled every label to the same 400-gallon tub, which makes the math easy to redo for yours.
How we picked these five
We compared label directions from the makers and spa retailers, Amazon ratings, and Amazon’s “Customers say” review summaries.
We didn’t test these in our own tub.
Doses below are the label numbers scaled to 400 gallons, rounded a bit.
Not sure how many gallons your tub holds? Check the manual or the maker’s spec page before you dose anything.
Hot tub shock compared at 400 gallons
| Product | Type | Label dose | Dose at 400 gal | Doses per container | Wait before soaking |
|---|---|---|---|---|---|
| Leisure Time Renew (2.2 lb) | Non-chlorine (MPS) | 2 oz per 250 gal | 3.2 oz | about 11 | 15 min, cover off |
| SpaGuard Spa Shock (35 oz) | Non-chlorine (MPS) | 1 oz per 300 gal weekly | 1.3 oz | about 26 | 15 min |
| AquaDoc Non Chlorine Shock (32 oz) | Non-chlorine (MPS) | 2 oz per 500 gal | 1.6 oz | about 20 | Run pump 30 min |
| SpaChoice Re-Energize (2 lb) | Non-chlorine (MPS) | 2 oz per 500 gal (listing) | 1.6 oz | about 20 | Run pump 30 min |
| Leisure Time Spa 56 (2 lb) | Chlorine (dichlor) | 1 oz per 500 gal to superchlorinate | 0.8 oz | about 40 | Until chlorine is back to 2-3 ppm |
MPS means potassium monopersulfate, an oxygen-based oxidizer that burns off sweat, lotion and oils without adding chlorine.
1. Leisure Time Renew: best all-round non-chlorine shock
Renew is the safe default if you use chlorine or bromine and just want clear water that doesn’t smell.
Leisure Time lists 32.18% potassium monopersulfate as the active ingredient.
It also doubles as the activator in the brand’s Reserve & Renew bromine system, at twice the normal dose.
It holds 4.7/5 from 4,900+ Amazon ratings (Nov 2026).
Skip it if you use the Leisure Time Free system, because the Amazon listing says it isn’t compatible.
- Soak again 15 minutes after dosing
- pH-buffered, so it shouldn’t push your pH around
- Reviewers mostly praise clear water and value
Cons:
- Highest dose per gallon here, so a 2.2 lb jar lasts only about 11 doses at 400 gallons
- Several reviewers say the lid had come off in the box
2. SpaGuard Spa Shock: most doses per container
SpaGuard’s non-chlorine shock is the one to get if you shock once a week and hate reordering.
The label asks for just 1 oz per 300 gallons weekly, with 2 oz per 300 gallons for the first treatment.
The label also says 2 tablespoons equal 1 ounce, which makes measuring easy.
It has 4.8/5 from 2,700+ Amazon ratings (Nov 2026).
Heads up: SpaGuard also sells an “Enhanced Shock” that contains chlorine, so check the name before you buy.
- About 26 weekly doses for a 400-gallon tub
- Doesn’t raise your chlorine or bromine reading
- Reviewers like the clear water and lack of smell
Cons:
- Heavy use means twice a week, which halves the doses
- Some reviewers wish the label print were bigger
3. AquaDoc Non Chlorine Shock: easy after-every-soak routine
AquaDoc fits people who like a simple rule: a small scoop after every soak.
The maker says 2 oz per 500 gallons after each use, then run the pump at least 30 minutes.
It also tells you to switch the jets on and off once or twice to mix it in.
It has 4.6/5 from 2,500+ Amazon ratings (Nov 2026).
Skip it if you use Baquacil, because AquaDoc says it isn’t compatible.
- Works alongside chlorine or bromine
- Reviewers say it keeps water clear and balanced
- About 20 doses per 32 oz tub at 400 gallons
Cons:
- Many reviewers say the container is very hard to open
- Longer circulation time than Renew or SpaGuard
4. SpaChoice Re-Energize: budget pick, but read the label
Re-Energize is the one to look at if you want an oxygen shock in a basic 2 lb bottle.
The Amazon title lists 3.76% active oxygen and 2 oz per 500 gallons after every use.
Some retailer copies of the label say 2 oz per 300 gallons instead, which would mean about 2.7 oz and only 12 doses at 400 gallons.
So go by the label on the bottle you actually get.
It has 4.6/5 from 2,900+ Amazon ratings (Nov 2026).
- Doesn’t raise chlorine levels, per the maker
- Reviewers say it clears murky water
- Simple pump-and-jets routine like AquaDoc
Cons:
- Dose instructions differ between sources
- Amazon’s review summary calls value and water quality mixed
5. Leisure Time Spa 56: chlorine shock for chlorine tubs
Spa 56 is chlorine granules, so it both sanitizes and shocks, which is handy if chlorine is already your sanitizer.
The maker says to superchlorinate every 2-4 weeks with 1 oz per 500 gallons, double the everyday dose.
Its active ingredient is sodium dichlor, listed at 55-56% available chlorine.
The 2 lb bucket has 4.7/5 from 7,500+ Amazon ratings (Nov 2026).
Skip it if you want to soak right away, because you have to wait until chlorine drops back to 2-3 ppm.
- One product covers daily chlorine and shock
- About 40 shock doses per 2 lb bucket at 400 gallons
- Reviewers say it’s easy to use and doesn’t smell strong
Cons:
- Longest wait before you can get back in
- Two different doses on one label, so it’s easy to mix them up
Which hot tub shock should you buy?
Start with your sanitizer, then pick by how often you soak.
- Bromine tub: a non-chlorine shock like Renew or SpaGuard
- Chlorine tub, soaking most nights: a non-chlorine shock after soaks, plus Spa 56 every 2-4 weeks
- Shock once a week: SpaGuard, because its weekly dose is the smallest
- Shock after every soak: AquaDoc or Renew
- Baquacil or other biguanide: none of these, use your system’s own oxidizer
Always test your water first, and follow the dose on your own bottle over any table, ours included.
Our hot tub test strips guide matches strips to each sanitizer.
If you’re also fighting foam, see our hot tub defoamer comparison.
And a dirty filter can undo a shock fast, so here’s our hot tub filter cleaner roundup.
Hot tub shock FAQ
How often should you shock a hot tub?
Most labels say weekly, plus after heavy use.
AquaDoc and SpaChoice say after every use, and Spa 56 says superchlorinate every 2-4 weeks.
How long after shocking can you get in?
Renew and SpaGuard say 15 minutes.
With chlorine shock, wait until your test reads 2-3 ppm again.
Chlorine or non-chlorine shock?
Non-chlorine shock cleans up oils and odors without raising your sanitizer level, so you can soak sooner.
Chlorine shock also kills germs, but only makes sense if chlorine is your sanitizer.
Is non-chlorine shock a sanitizer?
No.
Leisure Time, SpaGuard and AquaDoc all say their oxygen shocks don’t replace chlorine or bromine.
Sources
All checked November 9, 2026.
- Leisure Time Renew product page (dose, active ingredient, wait): https://shop.leisuretimeinc.com/products/renew-granular-2-2-lbs
- Leisure Time Spa 56 product page (doses, available chlorine): https://leisuretimeinc.com/collections/all-hot-tub-products-for-facebook-ads/products/spa-56-chlorinating-granules-2-lbs
- EPA label, Spa 56 Concentrated Chlorinating Granules (56% available chlorine): https://www3.epa.gov/pesticides/chem_search/ppls/007364-00080-20141223.pdf
- SpaGuard Spa Shock label text via Tarson Pools: https://tarsonpools.com/store/product/retail/spa-accessories/spa-chemicals/spaguard-spa-shock-oxidizer/
- AquaDoc Non-Chlorine Spa Shock product page (dose, pump time, Baquacil note): https://www.mavaquadoc.com/products/non-chlorine-spa-shock-for-hot-tub
- SpaChoice Re-Energize label text via Penny Part (2 oz per 300 gal version): https://pennypart.com/products/spa-choice-472-3-3041-re-energize-oxidizing-spa-shock-chemical-2-pound
- Amazon listings, ratings and “Customers say” summaries: ASIN B000LS2HEI, B077ZFZ9CX, B09QH1J61V, B005DGD93Q, B000NCW904