A DIY stock tank hot tub costs $250–$400 to set up if you already own the tank — and it heats to 104°F in about 2 hours. No $15,000 spa. No permit. No contractor. Just a propane tankless heater, a circulation pump, and the tank you already have. Here’s how to build it the right way.
What You Need — Full Parts List
Unlike a pool, a stock tank hot tub requires active heating and circulation. Water doesn’t stay hot on its own — you need a heater pushing hot water in while a pump keeps it moving. Here’s every component you need:
| Component | What to Get | Cost | Required? |
|---|---|---|---|
| Propane heater | Camplux 10L (most recommended) | ~$220 | ✅ Yes |
| Circulation pump | SEAFLO 3.3 GPM | ~$55 | ✅ Yes |
| Insulated cover | Polar Protector or standard cover | $70–$100 | ✅ Yes |
| Garden hose + fittings | 2× short hoses (in/out lines) | $15–$25 | ✅ Yes |
| Propane tank | Standard 20 lb (grill size) | $40–$60 | ✅ Yes (if not owned) |
| Chemicals | Bromine tablets + test strips | $20–$35 | ✅ Yes |
Camplux 6L vs 10L vs 16L — Which Heater Do You Actually Need?
The heater is the most important decision in this whole build. Too small and you’re waiting 4+ hours to heat up. The Camplux 10L is the right choice for 90% of builds.
| Model | BTU Output | Best Tank Size | Heat Time (300 gal) | Price |
|---|---|---|---|---|
| Camplux 6L | ~58,000 BTU | 6ft (150 gal max) | 4–5 hrs | ~$120 |
| Camplux 10L ✓ Best Pick | ~68,000 BTU | 6ft–8ft (up to 300 gal) | 1.5–2.5 hrs | ~$220 |
| Camplux 16L | ~117,000 BTU | 8ft–10ft (300–500 gal) | 1–2 hrs | ~$310 |
Camplux 10L Propane Tankless Water Heater — Best Pick
The most-recommended stock tank hot tub heater. 68,000 BTU, outdoor-rated, built-in ignition, adjustable temperature dial. Heats a 300-gal tank to 104°F in ~2 hours. Works with any standard 20 lb propane tank.
Best for 6ft tanks (150 gal or less). Lower BTU output means longer heat times on larger tanks, but great value for a compact setup.
117,000 BTU. Best for 10ft tanks or fastest heat times in cold weather. Heavier propane consumption — budget for it.
The Circulation Pump — Don’t Skip This
The heater needs water flowing through it to work. Without a pump, you get uneven heating — scalding near the inlet, cold everywhere else. The SEAFLO 3.3 GPM pump is the standard pairing for any Camplux build.
SEAFLO 3.3 GPM Circulation Pump — Required Pairing
The go-to pump for Camplux stock tank hot tub builds. Pulls water from the tank, pushes it through the heater in a continuous loop. Easy garden hose connections, quiet operation.
The Off-Grid Option: Chofu Wood-Fired Stove
No propane, no electricity, no problem. The Chofu wood-fired stove uses natural thermosiphon to circulate water through the tank without any pump. It’s the true off-grid stock tank hot tub setup — takes 2–3 hours to heat, but the experience is unmatched.
Chofu Wood-Fired Water Heater — Off-Grid Premium
Japanese-made wood-burning stove. No electricity, no propane — just wood. Thermosiphon circulation, stainless steel, lasts decades. The ultimate off-grid setup.
Step-by-Step Setup
- Fill the tank — fill to about 6 inches from the top.
- Mount the pump — run a hose from pump intake to a hole near the bottom of the tank.
- Connect the heater — pump output → Camplux cold inlet. Hot outlet → back into tank at top.
- Connect propane — attach regulator hose to 20 lb propane tank. Test for leaks with soapy water.
- Power up — turn on pump first, then ignite Camplux. Set to max temp.
- Cover while heating — keep insulated cover on during heat cycle. Cuts heat loss 30–40%.
- Add chemicals — dose bromine or chlorine before soaking. Circulate 15 minutes.
Heating Time + Propane Cost
| Tank Size | Heater | Summer Heat Time | Fall Heat Time | Propane Used |
|---|---|---|---|---|
| 6ft / 150 gal | Camplux 6L | 1.5–2 hrs | 2.5–3.5 hrs | ~0.5 lb |
| 8ft / 300 gal | Camplux 10L | 1.5–2.5 hrs | 2.5–4 hrs | ~1 lb |
| 10ft / 500 gal | Camplux 16L | 2–3 hrs | 3.5–5 hrs | ~1.5–2 lb |
Propane cost per soak: At ~1 lb per heat cycle for a 300-gallon tank, you’re paying about $1–$1.50 per soak. A full 20 lb tank gets you 15–20 heat cycles — a season of hot tubbing for less than a restaurant dinner.
Covers and Insulation
Best insulated cover option — foam core, waterproof outer shell, fits 6ft and 8ft tanks. Dramatically cuts heat loss overnight.
Standard cover for 8ft tanks. Keeps debris out, reduces evaporative heat loss. Good budget option.
Same cover sized for 6ft tanks. Lightweight, keeps heat in and debris out between uses.
Chemicals: Bromine vs Chlorine
Hot tub chemistry is different from pool chemistry — higher water temperatures break down chlorine faster. Most stock tank hot tub owners switch to bromine, which is more stable at 100°F+ and gentler on skin and eyes.
| Bromine | Chlorine | |
|---|---|---|
| Stability at 100°F+ | ✅ Excellent | ⚠️ Degrades fast |
| Smell | ✅ Mild | ⚠️ Strong at high temps |
| Skin/eye irritation | ✅ Gentler | ⚠️ More irritating |
| Cost | Slightly more expensive | ✅ Cheaper |
Complete Cost Breakdown
| Build Type | What’s Included | Est. Cost |
|---|---|---|
| Budget propane build | Camplux 6L + SEAFLO pump + cover (tank owned) | $250–$360 |
| Full propane build | 8ft tank + Camplux 10L + pump + cover + chemicals | $610–$890 |
| Premium build | Full propane + Polar Protector + deck platform + liner | $900–$1,400 |
| Wood-fired Chofu build | 8ft tank + Chofu stove + cover + chemicals | $1,750–$2,400 |
Frequently Asked Questions
How long does it take to heat a stock tank hot tub?
With the Camplux 10L and a 300-gallon tank starting at 65°F, expect 1.5–2.5 hours to reach 104°F in summer. Add 1–1.5 hours in fall. Keeping the cover on during heating cuts time by 20–30%.
Can you leave the heater running all night?
Camplux heaters are on-demand units, not designed for continuous overnight operation. The strategy is to heat fully, then use a high-quality insulated cover to hold temp. Most setups stay within 10–15°F of target over 6–8 hours with a good cover.
Can you use a stock tank hot tub in winter?
Yes — this is one of the best parts of a hot tub conversion. Key: don’t let the water freeze. Drain fully when not in use, or keep the heater on a maintenance cycle. Galvanized steel tanks can crack if water freezes inside.
Can I use my pool tank as a hot tub?
Yes. Many people use the same tank as a pool in summer and convert to hot tub mode in fall. The conversion takes about 30 minutes and disassembles just as fast.
Is a propane stock tank hot tub safe?
Yes, when set up correctly. Test propane connections with soapy water before igniting. Never use in an enclosed space. Keep the propane tank at least 3 feet from the heater. Camplux heaters have built-in overheat protection and flame failure shutoff.
Start With the Stock Tank Pool Guide
New to stock tanks? Start with our complete DIY stock tank pool guide — covers tank selection, liners, filtration, drain kits, and the full cost breakdown.