Can I Use Pool Parts on a Hot Tub? What Works, What Doesn’t and How

Last updated: September 2026

“Can I use pool parts on a hot tub?” A visitor to the website asked me this, and I thought it was such a good question that it deserved a post. I’ve been doing this a while now, so it’s really encouraging when a question comes in that I haven’t been asked before.

The short answer is: some of them, in the right place. Put the wrong pool part in the wrong place and your jets will be weak, your heater will throw flow errors and you’ll have spent more than you needed to. Here’s how to tell the difference.

Pool parts vs hot tub parts

First, the important bit. I’m going to talk about existing hot tub setups first. New builds, where you control the whole design, are different, and I’ll come to them further down.

In general, pool parts and hot tub parts don’t mix, because they’re designed for different jobs. Pool kit moves a lot of water slowly. Hot tub kit moves a little water fast, through jets. Regular readers of the blog or my YouTube channel will know I always say each gunite jet needs around 10 GPM of water flow. For 16 jets, that’s 10 × 16 = 160 GPM, and that’s what the pump has to deliver after the pipes, fittings and filter have taken their share. There’s more on the maths in How to correctly size a hot tub pump.

Many domestic pool sand filters top out at around 80 GPM (check the label on yours). Put one on the jet line and you’re at half the flow you need before you’ve even counted the friction. That’s the whole problem in a nutshell.

Which pool parts work on a hot tub?

Pool part	On the jet line of an existing tub	On a separate circulation loop (new build)
Skimmer	Yes	Yes
Sand filter	No, too restrictive for jet flow	Yes
Inline pre-filter / strainer	No, adds restriction	Yes, before the pump
Pool pump	No, not enough jet flow	Yes, and variable speed is ideal
Pool returns	No, they’re not jets	Yes, as the heated-water returns
Main drains	Only if the covers are rated for the jet pump’s flow	Yes, a pair with rated covers
Heater or heat pump	Not on the jet line	Yes
Chlorinator	No	Yes, after the heater

Pool parts you shouldn’t use on an existing hot tub

On an existing tub, where the jets share one pump and one set of pipes, avoid:

• Pool sand filters on the jet line. They’re too restrictive. See Can I use a sand filter on my DIY hot tub?
• Inline pool pre-filters, for the same reason. Every extra restriction on the suction side starves the pump.
• Pool returns as jets. They’ll return water, but they won’t give you a massage, and they don’t mix in air.

A starved pump doesn’t just give weak jets. It can cavitate, which is noisy and wears out the pump. See Noisy hot tub pump?

What matters with pool drains

It’s easy to lump pool drains in with sand filters as having about 80 GPM of flow, but the drain body isn’t really the issue. What matters is the cover. In the USA, suction outlet covers are tested and certified with a maximum flow rating, and every cover must be rated higher than the maximum flow of the system it’s on (see the ICC’s summary of the pool and spa code and CPSC drain cover guidance). So a pool drain is fine on a hot tub as long as its cover is rated for your jet pump. Fit two, at least 1m (3ft) apart, so a single blockage can’t trap anyone. See Installing a main drain.

Pool parts you can use on a hot tub

The skimmer

Most definitely. If your hot tub is outdoors, you want a skimmer. It collects debris off the surface and helps the flow into your pump and filter. I used a Certikin pool skimmer on my own tub, with a Waterway adaptor to go from its 63mm metric pipe to my 2in system. There’s a full guide in How to install a skimmer on your DIY hot tub, and more on metric vs imperial in Hot tub pipe: the ultimate guide.

Heaters and heat pumps

Pool heat pumps are widely used on hot tubs. The trick is to plumb them so they get the right flow without robbing the jets, usually on a circulation line. See The guide to air source heat pumps for hot tubs and How to add a circulation pump to a hot tub.

Pool automation systems

It’s also possible to use swimming pool automation systems, as the big pool brands (Jandy, Hayward and Pentair) design them to handle spas too. Pentair’s IntelliCenter, for example, comes in spa-capable versions and uses valve actuators to switch flow between pool and spa. Essentially, just like a spa pack, they’re a set of fancy relays with a control panel. Running a dual-speed pump, hot tub lights and an air blower are all possible.

Given the cost, though, you’re probably better off with a regular spa pack plus a WiFi module if you want phone control, like the Balboa ControlMySpa module (see my ControlMySpa review). The result is very similar and arguably much easier to set up. Automation makes more sense if you’re combining a pool and a hot tub, or running things like chlorinators and gas or propane heaters.

How to use pool parts on a new hot tub build

This may seem to contradict everything above, but it only applies to a brand-new build, where you control the whole plumbing design. The way to make pool parts work is to give them their own loop.

How it works

• The jet loop: a dedicated jet pump draws from its own pair of main drains and pushes straight to the jets and back. Nothing restrictive is in the way.
• The circulation loop: a second pair of drains (plus the skimmer) feeds a circulation pump. The water goes through the pump’s strainer basket or pre-filter, then the pump, a sand filter, the heater, and a chlorinator, and back into the tub through its own wall returns. You’d want two returns.

Where the pre-filter goes: it goes before the pump, to catch debris before it reaches the impeller. The rest of the order (pump, filter, heater, then back to the tub) matches every other system on this site. The chlorinator goes after the heater, so the heater doesn’t get a blast of concentrated chlorine.

Why not send the heated water back through the jets? Because when the jets are on full, the jet pump’s pressure can stop the circulation pump’s flow, even with a non-return valve. The flow stops, and the heater gives a flow error and shuts down (see Hot tub FLO error). With a completely separate heating and filtration loop, the jets are irrelevant. The dedicated jet pump takes care of them.

A small variable-speed pool pump is ideal on the circulation loop. It runs for hours on very little power, which is exactly what a pool pump is good at. Just keep both pumps below the water line, or use a self-priming pump. See What are the self-priming hot tub pump options?

What’s the downside?

The downside is cost. Pool parts cost more, from pumps to filters to anything with “swimming pool” in the name. I call it the “swimming pool tax”. A second loop also means more drains, pipes, joints and space in the control room. So why would you do it? A couple of reasons come to mind:

• Parts supply. In many areas it’s much easier to get hold of pool parts than hot tub parts, and a local pool shop can service them.
• Easy filtration for big or busy tubs. Sand filters cope well with a large volume of water and heavy debris, and you clean them by backwashing rather than taking out cartridges.

Sand or cartridge? Sand filters aren’t better at catching fine dust than cartridges. It’s the other way round. Trouble Free Pool puts sand at 20–40 microns and cartridges at 10–15 microns. Choose sand for convenience and volume, not finer filtration. More in Cartridge or sand filter?

Food for thought! If you’re thinking about sharing kit between an actual pool and a hot tub, read Why pool and hot tub plumbing should remain separate next.

Common mistakes

• Putting a sand filter on the jet line and wondering why the jets are weak.
• Using pool returns and expecting jets.
• Returning heated water through the jets, then chasing heater flow errors.
• Fitting pool drain covers that aren’t rated for the jet pump’s flow.
• Putting the pre-filter after the pump.
• Mixing metric pool fittings with imperial hot tub pipe without adaptors.

Planning your own build?

A two-loop system is very doable, but it needs designing up front. My DIY hot tub plans include a full plumbing layout and parts list. If you want a custom layout with pool parts, the Tub & Pool Designer Pro plumbing design service will draw it up, or the plumbing consultancy can work through it with you.

Looking for parts? Head to parts4tubs.co.uk in the UK or parts4tubs.com in the USA.

FAQs

Can I use a pool pump on a hot tub?

For circulation and heating, yes. As the jet pump, no. Pool pumps are built for volume at low pressure, and jets need around 10 GPM each.

Can I use a sand filter on a hot tub?

Yes, on a separate circulation loop. Not on the jet line, where it’s too restrictive.

Do sand filters filter better than cartridge filters?

No. Cartridges catch finer particles (about 10–15 microns vs 20–40 for sand). Sand’s advantages are volume and easy backwashing.

Can I use a pool skimmer on a hot tub?

Yes. It’s one of the best pool parts to use on an outdoor tub. Just check the pipe size and use an adaptor if it’s metric.

Can I use pool automation instead of a spa pack?

Yes. Pentair, Hayward and Jandy systems can run spas. For a hot tub on its own, though, a spa pack with a WiFi module is simpler and cheaper.

Thinking of using pool parts on your build? Drop your plan in the comments below. I read them all.

Cheers,
Andi

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Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Fast forward to 2025, I've helped over 1400+ DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi