How to Start Up and Maintain a Hot Tub with Bromine Tablets

Bromine tablets in a floating dispenser are the classic low-odor way to sanitize a hot tub. Bromine stays effective across a wider pH range than chlorine, regenerates with each shock, and many owners find it gentler on skin and sinuses. The one step most owners skip — and the reason many bromine tubs never work right — is the sodium bromide reserve at startup. This guide covers it all.

Big rule: Balance your water first — sanitizer comes second. Most hot tub problems aren’t sanitizer failures; they’re water balance problems.

Bromine and chlorine are different chemicals with different routines. They are not interchangeable, and chlorine products must never go into a bromine feeder or floater.

Who Bromine Tablets Are Best For

Bromine suits owners who want continuous sanitizing between soaks without daily dosing, are sensitive to chlorine odor, or run a busy tub where pH bounces around — bromine keeps working from pH 7.0 up past 8, where chlorine fades fast. The floater needs a top-up every week or two and the tablets cost a bit more than granules, but the routine is very forgiving. If you like the idea of bromine with even less of it in the water, see the FROG Serene system, which pairs minerals with a low bromine feed.

Products and Supplies You’ll Need

Leisure Time Brom Tabs — slow-dissolving bromine tablets.
Leisure Time Sodium Bromide (2 oz) — one startup treatment; the 16 oz bottle covers repeated refills.
Pentair bromine floating dispenser — adjustable-flow floater for the tablets.
4-way test strips (bromine, pH, alkalinity, hardness).
Leisure Time Renew non-chlorine shock — reactivates the bromide reserve (also in 5 lb).
Balancers: Alkalinity Increaser, Spa Up, Spa Down, Calcium Booster.
Hose pre-filter and Metal Gone for the fill.
Filter cleaner and a high-pressure rinse nozzle.
FROG Filter Mate mineral stick — optional upgrade that drops into your filter cartridge and adds FROG minerals to a bromine tub.

Leisure Time Brom Tabs

Pentair floating bromine tablet dispenser with adjustable flow ring

Pentair Bromine Floating Dispenser

Step 1: Prep, Fill, and Handle Metals

Before you fill

Rinse/clean the filters (or install new ones).
Open all jets, set valves normally, close the drain, check pump unions and drain plugs.
If the spa sat unused, purge the plumbing with a pipe & jet cleanser before the fresh fill.

Fill the right way

Fill through a hose pre-filter, through the filter compartment when your manufacturer allows it. On well water or with staining history, add Metal Gone right after filling. If bromine demand seems bottomless later, test for phosphates and treat with SeaKlear Free & Klear.

Step 2: Balance Your Water

Balance in this order: Total Alkalinity → pH → Calcium Hardness

Target ranges

Total Alkalinity: 80–120 ppm

pH: 7.2–7.6

Calcium Hardness: 150–250 ppm

Bromine tolerates pH drift better than chlorine, but your spa’s heater, seals, and shell don’t — keep balance in range regardless of sanitizer. Add balancers in small doses, one at a time, jets on, and retest before adding more.

Dosing: Hot tubs vary in size and water capacity. Always follow the dosage instructions on the product bottle for your hot tub’s gallon capacity.

Step 3: Start Up the Bromine System

1. Build the bromide reserve (the step everyone skips)

Tablets dissolve slowly — on a fresh fill, a floater alone can take a week to reach a safe bromine level. The fix is sodium bromide added right after balancing: the Leisure Time label calls for 1/2 oz per 100 gallons with the jets running, which establishes the bromide reserve the system needs. Calculate from your spa’s actual gallons and follow the bottle label.

2. Activate with shock

Shock with Renew non-chlorine shock per its label. The oxidizer converts the bromide reserve into active bromine sanitizer, giving you protection right away while the tablets come up to speed.

3. Load the floater

Fill the floating dispenser with Brom Tabs, start with the flow ring at a middle setting, and let it float. Never toss tablets loose into the spa — they’ll sit on the shell and bleach or stain it.

Step 4: First Week & Target Level

Test every day or two for the first week and adjust the floater’s flow ring until the water holds 2–4 ppm bromine (the Brom Tabs label’s residential range; commercial spas run 4–6 ppm). Reading low → open the ring a notch or add a tablet. Reading high → close it down a notch, and pull the floater out until the level falls back into range. Never soak with bromine below 2 ppm or in cloudy water.

Step 5: Weekly Maintenance Routine

Weekly “5-minute” routine

Test bromine daily if you can — the Renew label calls for daily bromine tests — and never less than 2–3 times per week (alkalinity → pH → bromine 2–4 ppm).
Check the floater weekly; top up tablets before it runs empty.
Superoxidize regularly with Renew — the Renew label’s dose is 4 oz per 250 gallons, jets on, cover off. Calculate from your spa’s actual gallons and follow the bottle. With bromine this does double duty, oxidizing contaminants and regenerating bromide back into active bromine.
Rinse filters weekly; deep-clean monthly with Leisure Time Filter Clean.
Hard water? Weekly Defender dose to prevent scale.
Wipe the waterline if a ring forms.

Remove the floater while soaking if you like (set it on a bleach-safe surface) — just put it back when you get out. Add sodium bromide again at every drain and refill; the reserve leaves with the old water.

Optional: add FROG minerals to your filter

The FROG Filter Mate mineral stick slips into your filter cartridge and adds the same FROG minerals used in the @ease and Serene systems to a traditional bromine tub. The minerals help control bacteria alongside your bromine — follow the package directions, and replace the stick every four months or at every drain and refill.

Troubleshooting

Bromine won’t register on the strip

No sodium bromide reserve? Fresh fills without it take ages to develop bromine from tablets alone. Add the reserve, then shock.
Shock with Renew — the reserve may be there but unactivated.
Open the floater’s flow ring or add tablets.
Persistent demand: test phosphates; clean the filter.

Bromine too high

Remove the floater, leave the cover off, and let the level drift down below 4 ppm before soaking. Then reduce the flow-ring setting.

Cloudy or dull water

Check balance, shock, and rinse or deep-clean the filter. Old water with high dissolved solids eventually stops responding — that’s a drain-and-refill, not another chemical.

When to Drain, Purge, and Refill

Plan on every 3–4 months for most households. Purge the plumbing with a pipe & jet cleanser before draining, speed the drain with a utility pump, and remember: fresh water means a fresh sodium bromide treatment before the floater goes back in.

Safety: Never mix bromine tablets with chlorine products, other sanitizers, or any other chemical — dry mixing can cause violent reactions or fire. Never put chlorine granules in a bromine floater or feeder, even an “empty” one; residue alone can react. Tablets go in a dispenser only, never loose in the tub. Store cool, dry, tightly closed, away from other chemicals.

Bromine Tablets FAQs

The Leisure Time Brom Tabs label calls for 2-4 ppm active bromine in residential spas (4-6 ppm commercial). Test daily when you can – the Renew label recommends daily bromine tests – and adjust the floater’s flow ring to hold the range. Don’t soak below 2 ppm or in cloudy water.

Tablets dissolve too slowly to protect a fresh fill – the sodium bromide startup treatment (label: 1/2 oz per 100 gallons) builds an instant bromide reserve that shock converts to active bromine immediately. Skip it and the tub runs unprotected for days. Repeat it at every drain and refill.

Never. Chlorine and bromine must not mix in concentrated form – combining them in a feeder or floater can cause a violent reaction or fire. If you want to switch a spa from bromine to chlorine, drain, purge, and refill first, and use a brand-new dispenser.

Regularly – every 1-2 weeks under normal use, and after heavy bather loads – with a non-chlorine oxidizer like Leisure Time Renew (label dose: 4 oz per 250 gallons, calculated from your spa’s actual capacity). In a bromine tub, shocking also regenerates the bromide reserve into active bromine, so levels typically rise after a shock.

Neither is universally better. Bromine holds up better in hot water and across a wider pH range, has less odor, and doses itself continuously from a floater. Chlorine granules cost less and act faster but need more frequent hands-on dosing. They are separate systems – pick one and never mix them.

Almost always a missing bromide reserve. Add sodium bromide per the label, shock with Renew, and you’ll have a reading the same day. If levels still fade fast afterward, test phosphates and deep-clean the filter – both quietly consume sanitizer.

Related EZ Water Care Guides

FROG Serene Floating System Guide

Bromine with mineral assist — up to 50% less bromine in the water, metered by a cartridge floater instead of loose tablets.

Blu Fusion TS Salt System Guide

Prefer generating bromine from sodium bromide salt automatically? The Blu Fusion TS startup and maintenance guide covers it step by step.

Browse all guides on the EZ Hot Tub Water Care hub.