I read the owner's manuals of ten spa makers, and the control panel guides from Balboa and Gecko. Their troubleshooting tables list the same handful of causes for weak jets, and the first six take minutes to check, with no tools.
The order below follows them: water, filter, pump speed, air, valves, jets, then air in the plumbing. The pump itself comes last, because it's the one thing on the list you shouldn't open.
Key takeaways
- Low water and a clogged filter are the two causes Hot Spring gives for weak or surging jets. Check both before anything else.
- On Hot Spring Hot Spot, Bullfrog and Balboa-controlled tubs, the first press of the jets button runs a two-speed pump on low. Press it again for high.
- The makers tell you to close the air controls after a soak to save heat. Open them again before you judge the jets.
- A pump that runs but moves no water after a refill has an airlock. Priming mode, and a loosened pump union if that fails, clear it.
- A pump that hums, buzzes or makes no sound needs a technician. So does a broken suction cover, and the tub stays off until it's replaced.
Start with what the jets are doing
| What the manuals point to | Start at | |
|---|---|---|
| All the jets weak or surging | Low water or a clogged filter | Steps 1 and 2 |
| Steady but gentle | Pump on low speed, or the air controls closed | Steps 3 and 4 |
| One seat or one jet weak | Diverter, a closed jet face or a blocked jet | Steps 5 and 6 |
| Pump runs, no water, after a refill | An airlock | Step 7 |
| Jets switch off on their own | A timer, or the pump overheating | Below the steps |
| Pump hums, buzzes or is silent | The pump or its power | Call a technician |
- 1
Check the water level
2 minHot Spring's manuals call weak or surging jets "an indication of a low water level condition or clogged filter cartridges." Arctic Spas explains the surging: the pump is sucking in air, which it says usually comes from low water.
Every maker sets its own level, so use yours:
- Caldera: an inch above the highest jet.
- Jacuzzi and Sundance: above all the jets but below the lowest pillow.
- Master Spas: up to the minimum level on the sticker near the filter.
- Cal Spas: 4 to 6 inches from the top.
Balboa says some of its systems detect low water and shut the pumps down until it's fixed, so a tub that's very low may not run at all.
- 2
Clean the filter and the suction screens
10 minA clogged filter is the other cause Hot Spring names. Its manual says a slow or stopped sweeping massage jet may mean the filter's pores are obstructed with dirt, body oils or calcification. Clean the cartridge properly, with a soak in filter cleaner, not just a rinse.
Turn the spa off first. Master Spas says that pulling the filter with the spa running can draw debris into the plumbing.
Then check what the water passes on its way to the pump. Hot Spring's Hot Spot manual lists clogged suction screens beside the filter, and Caldera lists a clogged suction cover or skimmer basket. Hot Spring also warns: "Do not use the spa with the suction screens removed."
- 3
Put the pump on high speed
1 minIf your jet pump has two speeds, Master Spas describes low speed as giving "gentle jet action" and high speed "maximum jet action."
On Hot Spring's Hot Spot models, Bullfrog and Balboa-controlled tubs, the first press of the jets button runs the pump on low and the second press switches it to high. Gecko's in.k300 panel flashes the pump light at low speed and shows it solid at high.
On a tub without a separate circulation pump, the jet pump also runs on low by itself to filter and heat. Cal Spas' troubleshooting table puts it simply: if the spa is in filtration mode, press the jets button to turn on high speed.
- 4
Open the air controls
1 minAir controls let air into the jets, and opening or closing them is how Master Spas says to raise or lower their force. Sundance, Jacuzzi and Master Spas all say to close them when the tub isn't in use, because the air cools the water. So they are closed whenever someone did what the manual says.
Which way they turn depends on the maker:
- Hot Spring: clockwise to open.
- Jacuzzi J-200: counterclockwise to open.
- Sundance: clockwise adds air.
- Cal Spas: counterclockwise adds air.
Hot Spring's sweeping massage jet needs its air lever fully open to move through its whole travel. And Sundance notes that some jets draw a little air even with the control closed, which it calls normal.
- 5
Set the diverter and open the valves
2 minA diverter sends the pump's water to one group of jets or splits it between them. Caldera says its spas aren't designed to give full power to all jets with the diverter in the middle. For full power, turn it toward the seat you're in.
Caldera puts a stiff diverter down to sand or grit inside it, and Master Spas warns that sand will make one seize. Master Spas also says to turn it only with the pump off.
Then open the equipment door and look at the shut-off valves on the plumbing. These are also called gate or slice valves. Marquis warns that a new or recently serviced spa may have them partly closed, which restricts flow. Master Spas says they must be completely open in normal use, and Cal Spas says never to run the spa with them closed.
- 6
Open the jet faces, and clear a blocked jet
10 minOn Master Spas, Marquis and Arctic tubs, turning the face of a jet opens or closes it, and Hot Spring's Hot Spot manual says its combination jet faces can be turned to shut the flow off completely. Go round the tub and open them.
Not every jet works like that. Caldera says its Euro Directional and Euro-Pulse jets don't regulate the force, and asks owners not to try to rotate their faces. Bullfrog's JetPak valves reduce the flow but won't stop it completely.
The direction isn't standard here either. Arctic turns clockwise for a stronger flow, and Waterway's in-ground spa jet turns clockwise to reduce it. Check your manual.
Don't close too many at once. Bullfrog says closing jets pushes more pressure to the others on the same pump, and never to shut them all at the same time. Balboa lists "too many closed jets" among its flow faults.
A blocked jet can come out. Caldera says to remove the jet face eyeball and clean the opening behind it. Master Spas removes its jets by turning them counterclockwise until they release, then soaks them overnight in white vinegar for grit and mineral deposits. Cal Spas says the jet will be snug, to turn it off first, and in capitals, "DO NOT PRY OUT JETS."
- 7
Clear an airlock
15 minThe sign is a pump that runs while no water comes out of its jets, after the tub has been drained and refilled. Hot Spring, Jacuzzi and Caldera all list that combination as a pump that hasn't primed.
Priming mode comes first. Balboa, Jacuzzi and Sundance controls go into it when the power comes on, for about four minutes, and the heater won't run during it. Balboa says nothing switches on by itself; you press the jets button twice to run the pump on high. Its TP200 guide gives the clearest test: "Priming is complete when water flows from the jets without air bubbles." Prime one pump at a time, so you can see which one is moving air.
Don't let it run dry. Balboa says to stop a pump that hasn't primed after 2 minutes and start again. Switching it off and on can help, it says, but not more than five times, and if it still won't prime, shut off the power and call for service. The Gecko documents I read describe no priming mode, so on a Gecko-controlled tub, follow the spa maker's manual.
If it won't prime, let the air out. The makers' methods differ:
- Hot Spring and Caldera: turn the power off at the breaker, loosen the union on top of the pump to let the air escape, hand-tighten it, and power back on.
- Jacuzzi: take out the filter cartridge, hold a garden hose over the filter fitting with a rag as a seal, and have someone run the water for 30 seconds.
- Bullfrog: remove the clamp on the pump's air bleed line until water flows, then reconnect it.
- Master Spas: loosen the union on the pump's outlet while it tries to prime.
With 240 volts in that cabinet, I'd follow the power-off versions.
Next time, fill it differently. Master Spas and Cal Spas recommend filling through the filter compartment, and Jacuzzi and Sundance suggest it if you get an airlock filling from the footwell. Bullfrog says to open every valve and jet before filling. Cal Spas also soaks a new filter cartridge for 30 minutes first, because air trapped in a dry cartridge can stop the pump priming. Draining and refilling a hot tub covers the whole fill.
Jets that switch themselves off
Check the timer first. The control turns the jets off after a set run. Balboa's TP600 and TP400 panels turn high speed off after 15 minutes and low speed after 30. Marquis runs high speed for 15 minutes, then low for 15. Bullfrog's pumps run for 30 or 60 minutes per press.
An overheating pump. Bullfrog says blocked vents on the equipment door can make the pump overheat and shut off. Master Spas says running high speed past its 15-minute timeout again and again can make the motor shut itself off to cool. Cal Spas says to let an overheated pump cool for an hour.
A flow code. If the panel shows one, it's telling you the same thing as the steps above:
- FLO or NO FLO (Gecko): "Check filter, pump, blockage, air lock and water level."
- HFL, LF or dr (Balboa): flow through the heater is too low. Balboa's checklist is low water, suction restrictions, closed valves, trapped air, too many closed jets and pump prime.
HL on a Gecko panel is not a flow code. It means the water in the heater has reached 119°F, and Gecko and Hydropool both say not to get in. Leave that one to a technician.
When it's the pump
If you've worked through all seven steps and the jets are still weak, the makers send you to a technician:
- No sound, or a buzz. Sundance says if the pump makes no sound, or buzzes, to turn the power off and call the dealer. Master Spas says the same about no sound.
- Won't prime. Balboa says to shut off the power and call for service.
- A noisy pump. Cal Spas lists debris inside the pump and noise from damage among the causes, and sends both to the dealer.
The pump makers' own troubleshooting tables show why. Gecko's XP2e manual lists low voltage, a motor shaft that won't turn and a jammed impeller for a pump that hums but won't start. Waterway's pump instructions add a failed capacitor and send it to a motor service center. Gecko's control packs, its troubleshooting guide says, contain no user-serviceable parts.
Go deeperIf the water's cold tooA heater with no flow shuts itself off. The checks overlap.The suction cover stays on
Clearing a blocked suction cover is fine. Running the tub without one isn't.
The most recent CPSC report on circulation entrapment I could find covers 2014 through 2018 and counts 11 victims. Seven were in spas or hot tubs, six had their hair caught, and four of the incidents involved missing or removed covers. CPSC's guidelines explain how hair entrapment happens. Long hair gets swept into the holes of the cover and tangles there: "Entrapment occurs because of the tangling, and not necessarily because of strong suction forces."
Master Spas, Marquis, Arctic, Hydropool and Waterway all say never to run a spa with a suction fitting broken or missing. Master Spas and Waterway put a cover's life at 7 years. Marquis says that if any part of the body is drawn to a fitting, turn the jet pumps off immediately.
Replace a cover with the right part. Federal law requires every spa drain cover sold in the U.S. to meet the anti-entrapment standard, portable hot tubs included. CPSC still had to recall spa suction covers sold on Amazon in June 2026 for failing it. Buy the part your spa's maker specifies.
Where the makers disagree
- Venting an airlock with the pump on or off. Master Spas loosens the union while the pump tries to prime, and Gecko's troubleshooting guide starts the pump first. Hot Spring, Caldera, Marquis, Hydropool and Cal Spas all turn the power off first. I'd turn it off.
- How to prime. Balboa runs each pump on high for up to 2 minutes. Hydropool starts on low and expects water within 15 seconds. Jacuzzi's J-300 says to press the jets button several times without leaving the motor running more than 5 to 10 seconds at a time.
- The diverter while the tub is covered. Jacuzzi says to leave its valve on the combination setting when the spa is covered, for filtration. Cal Spas says never to leave its diverter in the center during filtration, because the pump then can't draw enough to inject ozone.
For the filter
- Check price
filter cleaner
A hose rinse leaves the oils behind. This is what gets the greasy film.
Frequently asked questions
Why are my hot tub jets weak?
Start with the two causes Hot Spring names: low water and a clogged filter. After those, the makers list the pump running on low speed, closed air controls, a diverter set in the middle, jet faces turned off, closed shut-off valves and blocked suction covers. All of those are free to check. A pump that hums or makes no noise needs a technician.
Why do my hot tub jets surge on and off?
Low water, according to Cal Spas, Caldera, Hot Spring and Arctic. Arctic Spas says surging jets mean the pump is sucking in air, which it says usually comes from a low water level. Hot Spring and Caldera add a clogged filter. Top the water up to your maker's level and clean the filter.
How do I get an airlock out of my hot tub?
Use priming mode, which Balboa, Jacuzzi and Sundance controls enter when the power comes on. Run each pump on high, one at a time, and watch for water flowing without bubbles. Balboa says to stop a pump that hasn't primed after 2 minutes and start again, and that switching it off and on can help, but no more than five times. If it still won't prime, the makers say to let the air out at the pump, for example by loosening a union, then tighten it again.
Why do my hot tub jets turn off by themselves?
Check the timer first. Balboa's panels turn high speed off after 15 minutes and low speed after 30, and Bullfrog's pumps run 30 or 60 minutes per press. A pump that stops sooner may be overheating: Bullfrog says blocked vents on the equipment door can cause it, and Master Spas says running high speed past its timeout again and again can make the motor shut itself off to cool.
Which way do hot tub air controls turn?
It depends on the maker, so check your manual. Hot Spring opens its air controls clockwise, Jacuzzi's J-200 counterclockwise, Sundance adds air clockwise, and Cal Spas adds air counterclockwise.
When should I call a technician about hot tub jets?
When the pump hums, buzzes or makes no sound at all, which Sundance and Master Spas send to the dealer. Also when it won't prime after the steps in the manual, when it gets noisy, or when the panel keeps showing a flow error after you've cleaned the filter and checked the water. Gecko says its control packs contain no user-serviceable parts.
