Description
Six Yellow Bromine Cartridges, About Half a Season or More, Shipped Free
The Spa Frog Serene Bromine Cartridge 6 Pack holds six yellow 150 g bromine refills for FROG Serene Floating and In-Line systems. At 2 to 4 weeks each, that is about three to six months of bromine for one hot tub.
It covers roughly one full mineral cycle and ships free to US addresses on online orders at HotTubPirate.com.
Lines Up With a Full Mineral Cycle
The blue mineral cartridge lasts 4 months. Six bromine cartridges at 2 to 4 weeks each run about three to six months, so one box typically carries you through a whole mineral cycle.
Free US Shipping on Online Orders
The 6 Pack ships free within the US when you order online at HotTubPirate.com, so stocking up costs nothing extra to deliver.
Enough for Two Hot Tubs
Running two Serene floaters? Six cartridges keep both supplied for about six to twelve weeks, depending on use.
Fewer Reorders, Same Genuine Cartridge
Each cartridge is the standard FROG Serene 150 g yellow refill. Buying six at once means fewer orders and no gap between cartridges.
Key Features and Benefits
- 6 Yellow Cartridges150 g of prefilled bromine each.
- About 3–6 MonthsFor one hot tub at 2 to 4 weeks each.
- Free US ShippingOn online orders at HotTubPirate.com.
- Floating or In-LineGoes in beside the mineral.
- Adjustable 0–6Matched to 200 to 600 gallons.
- Two-Tub FriendlyKeeps two floaters supplied.
- EPA RegisteredEPA Reg. No. 53735-16.
Product Details
| Product Detail | Information |
|---|---|
| Brand | FROG (King Technology, Inc.) |
| Product | Spa Frog Serene Bromine Cartridge - 6 Pack |
| Pack Size | 6 cartridges |
| Cartridge Size | 150 g (5.3 oz) net per cartridge |
| Total Contents | 900 g (6 × 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 (6 single cartridges) |
| Store SKU | 01-14-3824-6 |
| UPC | 722906038214 (single cartridge) |
| Estimated Supply | About 3 to 6 months for one hot tub |
| Image Alt Text | Six yellow Spa Frog Serene 150 g bromine cartridges in two rows for FROG Serene Floating and In-Line systems, 6 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 2 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 (this listing) | About 3–6 months |
| 12 Pack | 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 6 Pack
Six genuine yellow cartridges cover about a full mineral cycle for one hot tub, or keep two Serene floaters running, and they ship free on online orders. Shop the full FROG Serene line, or compare every hot tub bromine option at HotTubPirate.com.
Ideal For
- A full 4-month mineral cycle
- Two-hot-tub households
- FROG Serene Floating and In-Line owners
- Fewer reorders
- Shoppers who want free shipping
Frequently Asked Questions
How many months does a 6 pack of Serene bromine cartridges cover?
About three to six months for one hot tub. FROG rates each yellow cartridge at 2 to 4 weeks, so your soaking schedule decides where in that range you land.
Do these fit the built-in FROG cartridge holder in my hot tub?
Yes, when it is a FROG Serene In-Line holder. A built-in holder means you have the Serene In-Line System, which takes these yellow 150 g cartridges or the larger green 200 g size. Check that the cap says Serene, not @ease.
Can the empty cartridges be reused?
No. FROG labels them non-refillable. Once a cartridge is empty, drain it and discard or recycle it, then open the next one from the pack.
Do I set every cartridge to the same number?
Usually, yes. Once you find the number that holds 1.0 to 2.0 ppm in your hot tub, start each new cartridge there, then adjust one step if your readings drift.
How many bromine cartridges does a hot tub use in a year?
At 2 to 4 weeks each, roughly 13 to 26 a year for one hot tub. A 6 pack covers about a quarter to half of that.
Can two hot tubs share a 6 pack?
Yes. Each cartridge works on its own in one Serene floater, so two hot tubs can draw from the same box. Expect about six to twelve weeks for both.
Do I pay for shipping on six cartridges?
Not within the US. Online orders at HotTubPirate.com over $50 ship free, and the 6 Pack qualifies on its own.
How should I store the spare cartridges?
Keep them in the original packaging, tightly closed and upright, somewhere cool and ventilated at or below 86°F, locked up and away from other chemicals, per the Safety Data Sheet.
Do unused bromine cartridges expire?
No expiration date appears in the product details we reviewed. Storing them sealed, cool and dry helps them stay in good condition until you need them.
Do I use FROG Jump Start with FROG Serene?
Yes, at each fresh fill. FROG's floating manual calls for a starting level of 1.0 to 2.0 ppm with one Jump Start packet per 600 gallons before the cartridges go in.
Why does FROG say not to use dichlor shock with Serene?
Dichlor adds cyanuric acid. FROG's manual says that buildup reduces how well the Serene bromine cartridge works, so it recommends FROG Maintain non-chlorine shock instead.
Can I put the contents in an automatic bromine feeder?
No. Do not open the cartridges. The label also warns against using this product in any device that has been used with calcium hypochlorite.
How is FROG Serene different from using bromine tablets alone?
Serene pairs a metered bromine cartridge with a mineral cartridge. FROG says that lets the water hold up to 50% less bromine than the ANSI minimum of 2.0 ppm, without handling loose tablets.
Why does my bromine use jump when the mineral cartridge gets old?
Past the 4-month mark the minerals are used up, so bromine has to do all the work. FROG says the hot tub then needs more bromine, which empties these cartridges faster.
Do I need gloves to change a cartridge?
Gloves and eye protection are a good idea. The Safety Data Sheet lists the bromine as corrosive to skin and eyes, and draining an old cartridge can leave residue on your hands.
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.