Description
Twelve Yellow Bromine Cartridges for Busy Hot Tubs, Shipped Free
The Spa Frog Serene Bromine Cartridge 12 Pack is twelve yellow 150 g bromine refills for FROG Serene Floating and In-Line systems. That is about six to eleven months of bromine for one hot tub, or a steady supply for rentals and homes with more than one hot tub.
It is the largest Serene bromine size we carry and ships free to US addresses on online orders at HotTubPirate.com.
Most of a Year in One Order
Twelve cartridges at 2 to 4 weeks each add up to roughly six to eleven months for one hot tub. Pair the box with two or three blue mineral cartridges and you are set for most of the year.
Built for Rentals and Heavy Use
Vacation rentals, large families and frequent soakers go through bromine faster. A dozen cartridges on hand means a fresh one is always ready.
Free US Shipping on Online Orders
The 12 Pack ships free within the US when you order online at HotTubPirate.com.
Key Features and Benefits
- 12 Yellow Cartridges150 g of prefilled bromine each.
- About 6–11 MonthsFor one hot tub at 2 to 4 weeks each.
- Rental and Multi-Tub ReadyKeeps several floaters supplied.
- Free US ShippingOn online orders at HotTubPirate.com.
- Floating or In-LineFits the floater or built-in holder.
- Adjustable 0–6Matched to 200 to 600 gallons.
- EPA RegisteredEPA Reg. No. 53735-16.
Product Details
| Product Detail | Information |
|---|---|
| Brand | FROG (King Technology, Inc.) |
| Product | Spa Frog Serene Bromine Cartridge - 12 Pack |
| Pack Size | 12 cartridges |
| Cartridge Size | 150 g (5.3 oz) net per cartridge |
| Total Contents | 1,800 g (12 × 150 g) |
| Cartridge Color | Yellow |
| Product Type | Prefilled bromine sanitizer cartridge for hot tubs |
| Active Ingredient | BCDMH (1-bromo-3-chloro-5,5-dimethylhydantoin), 98.0% |
| Other Ingredients | 2.0% |
| Contents Form (SDS) | White tablets or granules sealed inside the cartridge |
| Made For | FROG Serene Floating System and FROG Serene In-Line System |
| Use With | FROG Serene Mineral Cartridge (blue), set to #6 |
| Hot Tub Size | About 200–600 gallons on the setting chart |
| Adjustable Settings | 0 to 6, matched to hot tub gallons |
| Target Bromine Level | 1.0–2.0 ppm, at least 1.0 ppm at all times |
| Water Balance (Floating Manual) | pH 7.2–7.6, total alkalinity 80–120 ppm, total hardness 150–250 ppm, TDS under 1,500, cyanuric acid 0–50 ppm |
| Typical Cartridge Life | About 2 to 4 weeks, depending on hot tub size and use |
| Refillable | No |
| Recommended Shock | FROG Maintain non-chlorine shock, weekly or as needed |
| Holder or Floater Included | No |
| Hazard Classification (SDS) | Danger: corrosive, causes severe skin burns and eye damage, harmful if swallowed or inhaled, may cause an allergic skin reaction, oxidizer |
| Storage | Original packaging, tightly closed and upright, cool and ventilated, at or below 86°F (30°C), locked up |
| Shipping Note (SDS) | Shipped under Limited Quantities provisions |
| EPA Registration No. | 53735-16 |
| California Registration No. | 53735-16-AA |
| Manufacturer Part Number | 01-14-3824 (12 single cartridges) |
| Store SKU | 01-14-3824-12 |
| UPC | 722906038214 (single cartridge) |
| Estimated Supply | About 6 to 11 months for one hot tub |
| Image Alt Text | Twelve yellow Spa Frog Serene 150 g bromine cartridges in two rows of six for FROG Serene Floating and In-Line systems, 12 pack |
How to Use the FROG Serene Bromine Cartridge
- Balance the water first: Test with FROG Test Strips and adjust total alkalinity to 80–120 ppm, then pH to 7.2–7.6, then hardness to 150–250 ppm. Add one balancer at a time with the jets on and wait 6 hours before retesting.
- Start up with FROG Jump Start: After a fresh fill, set a starting level of 1.0–2.0 ppm with one Jump Start packet per 600 gallons. FROG says not to use a non-chlorine shock at start-up.
- Set both cartridges: Turn the blue mineral cartridge to #6. Turn the yellow bromine cartridge to the number on the setting chart for your hot tub's gallons.
- Snap them into the floater: Push both cartridges into the openings of the green FROG Serene Floating System holder until they stay in place, then let it float in the hot tub.
- Fine-tune for a week: Test daily for the first week and move the bromine cartridge up or down one number per day until the strip matches 1.0–2.0 ppm.
- Swap the yellow cartridge when empty: Replace it when it runs out, usually every 2 to 4 weeks. Drain the water out of the old one, then discard it or recycle it where available.
FROG Serene Bromine Cartridge Setting Chart
| Hot Tub Size | Bromine Cartridge Setting |
|---|---|
| 200 gallons | 0 |
| 250 gallons | 1 |
| 300 gallons | 1 |
| 350 gallons | 2 |
| 400 gallons | 3 |
| 450 gallons | 4 |
| 500 gallons | 5 |
| 550 gallons | 5 |
| 600 gallons | 6 |
From the FROG Serene Floating and In-Line manuals. The blue mineral cartridge always goes on #6. For the first week, test daily and move the bromine cartridge up or down one setting per day until the strip reads 1.0 to 2.0 ppm bromine.
Compatibility Notes
Before You Buy
- This is the yellow 150 g FROG Serene Bromine Cartridge. FROG's 2026 catalog lists it for both the FROG Serene Floating System and the FROG Serene In-Line System.
- In a built-in FROG Serene In-Line holder it goes in the bottom position, under the blue mineral. FROG also makes a larger green 200 g bromine cartridge, mainly for in-line holders. FROG Serene bromine cartridges of either size work in both the floater and in-line holders.
- It needs a blue FROG Serene Mineral Cartridge alongside it. FROG notes the lower bromine level only applies when FROG minerals are in use.
- Not for FROG @ease systems, which use SmartChlor chlorine cartridges instead of bromine.
- Sized for hot tubs from about 200 to 600 gallons on the setting chart. FROG's floating system page lists hot tubs of 150 to 600 gallons.
- The cartridge holder or floater is not included. This listing is the replacement cartridge only.
Which FROG Serene Cartridge Do I Need?
| Cartridge | Made For | Replace |
|---|---|---|
| FROG Serene Mineral Cartridge (blue) | Serene Floating and Serene In-Line | Every 4 months, or at each drain and refill |
| FROG Serene Bromine Cartridge, 150 g (yellow) (this listing) | Serene Floating and Serene In-Line | When empty, about every 2 to 4 weeks |
| FROG Serene In-Line Bromine Cartridge, 200 g (green) | Mainly Serene In-Line (also fits Floating) | When empty, about every 2 to 4 weeks |
| FROG Serene Cartridge Kit (1 blue + 3 yellow) | Serene Floating or In-Line refill | One mineral cycle plus three bromine changes |
| FROG Serene In-Line Refill (1 blue + 1 green) | Serene In-Line refill | One mineral cycle plus one bromine change |
| FROG @ease cartridges | FROG @ease systems only | Separate SmartChlor system, not interchangeable with Serene |
Colors help you tell them apart: blue is always the mineral, yellow is the 150 g bromine and green is the larger 200 g bromine, made mainly for in-line holders. Either bromine size fits both Serene systems.
How Long Each Pack Lasts
| Pack | One Hot Tub, One Cartridge at a Time |
|---|---|
| 1 cartridge | 2–4 weeks |
| 3 Pack | About 6–12 weeks |
| 6 Pack | About 3–6 months |
| 12 Pack (this listing) | About 6–11 months |
Based on FROG's 2 to 4 week cartridge life. Large hot tubs, frequent soaks and heavy bather loads empty cartridges sooner. Remember the blue mineral cartridge also needs replacing every 4 months.
Why Choose the Spa Frog Serene Bromine 12 Pack
One box of genuine yellow cartridges covers most of a year for a single hot tub, or keeps busy and rental hot tubs supplied, and it ships free on online orders. Shop the full FROG Serene line, or compare every hot tub bromine option at HotTubPirate.com.
Ideal For
- Vacation rentals
- Homes with two or more hot tubs
- Frequent soakers
- Most of a year of bromine
- Shoppers who want free shipping
Frequently Asked Questions
Is a 12 pack enough bromine for a full year?
For many hot tubs it covers most of one. At FROG's 2 to 4 weeks per cartridge, twelve last about six to eleven months. A lightly used hot tub gets closest to a year.
I have a built-in FROG holder. Should I buy the yellow or the green cartridge?
Either works. FROG's 2026 catalog lists the yellow 150 g for the In-Line System, and FROG also makes a green 200 g cartridge that holds more bromine per change. This pack is the yellow 150 g size.
Can I refill these cartridges to make the pack last longer?
No. FROG labels them non-refillable. Using a fresh cartridge each time keeps the bromine output matched to the setting chart.
What is the setting for a 400 gallon hot tub?
Setting 3 on FROG's chart. Smaller hot tubs use lower numbers, down to 0 at 200 gallons, and larger ones go up to 6 at 600 gallons.
What does FROG mean by Fresh Mineral Water?
It is FROG's name for water treated with its minerals plus a low level of sanitizer. FROG describes it as cleaner, clearer, softer and easier to care for than bromine alone.
What is BCDMH?
BCDMH is bromochlorodimethylhydantoin, the active ingredient in the cartridge at 98.0%. It dissolves slowly in water and releases bromine to sanitize.
Does the FROG Serene bromine cartridge add cyanuric acid?
No. BCDMH is a hydantoin, not a cyanurate, so it does not add cyanuric acid. That is one reason FROG recommends non-chlorine FROG Maintain instead of dichlor shock with Serene.
Can I recycle the empty cartridges?
FROG's manual says to drain each spent cartridge and discard it in the trash or offer it for recycling if available. Check what your local program accepts.
Can I use FROG Serene cartridges in a swim spa?
The Serene setting chart covers hot tubs from 200 to 600 gallons. Swim spas hold far more water, so these cartridges are not sized for them.
Does the 12 pack include the floating holder?
No. The pack is twelve replacement cartridges only. They go into the FROG Serene floater or built-in Serene holder you already have, beside the blue mineral cartridge.
How many mineral cartridges go with 12 bromine cartridges?
Two or three. Twelve bromine cartridges last about 24 to 48 weeks, and the blue mineral cartridge is replaced every 4 months, or at each drain and refill.
What does 5.3 oz on the label mean?
That is the net weight of bromine sanitizer in each cartridge, 150 g. Across the 12 pack it comes to 1,800 g of prefilled bromine.
Do I need to drain the hot tub to change a bromine cartridge?
No. Swap the yellow cartridge whenever it empties. Draining and refilling follows your hot tub maker's schedule, and that is when FROG says to replace the blue mineral cartridge too.
What else should I keep on hand with FROG Serene?
FROG Test Strips, FROG Maintain for weekly shocking, a FROG Jump Start packet for each fresh fill and a blue FROG Serene Mineral Cartridge for each 4-month change.
Can I buy the blue mineral cartridge separately?
Yes. The FROG Serene Mineral Replacement Cartridge is sold on its own and as a 2 pack, so you can add one for every 4-month change alongside this box of bromine.
Safety Notes
Handle With Care
- Danger: corrosive. The bromine inside causes severe skin burns and eye damage and is harmful if swallowed or inhaled. Wear gloves and eye protection when you handle or drain a cartridge.
- Do not open, break or refill the cartridge, and do not handle a damaged cartridge without protective gear.
- Strong oxidizer. Keep it away from heat, flames and combustible materials, and never mix it with other chemicals.
- Do not use it in a feeder or other device that has been used with calcium hypochlorite.
- If it gets in the eyes, rinse cautiously with water for several minutes, remove contact lenses if easy to do, keep rinsing and call a poison center or doctor right away.
- Store cartridges in the original packaging, tightly closed and upright, in a cool, well-ventilated place at or below 86°F (30°C), locked up and away from children and pets.
Product Documents
Download the FROG Serene Floating System and In-Line System manuals for the setting chart and replacement steps, plus the official Safety Data Sheet for the bromine cartridge.