Hot Tub Bromine Granules BDCMH

Fast-acting bromine granules for hot tubs and spas. This BCDMH-based granular sanitiser sets up a bromine bank, then keeps the water gentle on bather skin and steady through wide pH swings.

• Sets up a bromine bank for ongoing sanitisation.
• Sanitises across a wider pH band (7.0-7.8) than chlorine.
• Stays effective at hot-tub temperatures up to 40 C.
• Produces fewer eye-stinging by-products than chlorine.
• Runs alongside Bromine Tablets 20g for a steady ongoing dose.

Sizes and prices

Available in 1kg, 2.5kg, 5kg, 10kg, 20kg, 25kg.

• 1kg: £16.18
• 2.5kg: £28.33
• 5kg: £48.58
• 10kg: £89.09
• 20kg: £170.10
• 25kg: £210.60

How to use

1. Test bromine, pH and total alkalinity with a fresh kit.
2. Balance pH to 7.2-7.6 and alkalinity to 80-120 ppm before dosing.
3. On a fresh fill, dose 25 g per 1000 L, pre-dissolved in 5 L of warm water.
4. Switch the jets to full and pour the solution evenly across the surface.
5. Circulate for 60 minutes, then retest bromine.
6. For top-ups, dose 5 g per 1000 L whenever bromine reads under 4 ppm.

Frequently asked questions

What bromine level should I aim for?

4-6 ppm total bromine for hot tubs and spas, with pH at 7.2-7.6.

How often should I dose?

Top-up every 2-4 days; refresh the initial bank weekly after a water change.

Can I bathe straight after dosing?

Wait for bromine to read under 8 ppm, usually 30-60 minutes after dosing.

How long does 1 kg last?

Around 5-6 months of top-ups for a 1500 L hot tub.

Are bromine granules easier on sensitive skin?

Yes. Bromine forms fewer skin-irritant by-products than chlorine and is the standard choice for sensitive bathers.

Should I use granules or tablets?

Granules are for fast top-ups and the initial bank; tablets are for a slow daily release. Most people run both together.

What is the active ingredient?

Bromochlorodimethylhydantoin (BCDMH) at >= 60% available halogen.

Why do bromine systems need a bank?

Bromine cycles between active HOBr and spent bromide. The bank is the bromide reserve that the chlorine fraction in BCDMH keeps re-oxidising.

Does bromine raise total dissolved solids?

Yes. Heavy long-term dosing pushes TDS up, so refresh the water once TDS passes 1500 ppm.

Bromine not climbing?

Raise pH to 7.4 and dose at the initial bank rate.

Strong bromine smell?

Shock with MPS at 17 g per 1000 L and ventilate for 30 minutes.

pH drifting up?

Dose pH minus weekly; bromine systems run at a higher pH than chlorine.

Bromine granules or tablets?

Granules dissolve fast for instant top-ups. Tablets give a slow, steady release. Run both together for stable hot tub care.

Bromine or stabilised chlorine?

Bromine is gentler at hot tub temperatures. Stabilised chlorine is more cost-effective for outdoor pools with heavy UV.