The Best Hot Spring Filters: Tri-X and the Alternatives

The verdict, up front. Hot Spring’s Highlife tubs use Tri-X ceramic filter elements, and they are genuinely different from an ordinary pleated cartridge: they are designed to be washed and reused over a long service life rather than replaced every season. They also cost several times what a pleated filter costs, and most of these tubs take three to five of them.

That combination produces the single most common Hot Spring problem we see, which is not a filter fault at all. Faced with the price of a full set, owners put the replacement off, and the tub runs for years on elements that stopped filtering properly a long time ago. This page covers both the real thing and the pleated alternative, because the honest answer for some households is the cheap filter that actually gets changed.

How we judged these

What Tri-X actually is

A Tri-X element is ceramic rather than pleated paper or polyester. The practical consequence is that it tolerates being washed repeatedly: rinse it, and when rinsing stops being enough, clean it more aggressively without destroying the media. A pleated cartridge eventually blinds off no matter how you treat it, because the fibers pack with fine debris and never fully release it.

The part number has moved. Current listings show 79435, which replaced 73250, and describe a newly designed, more durable exterior layer on the current version. If you are matching against an old element or an old invoice, both numbers belong to the same family, so do not assume you have found the wrong part.

How many do you need?

This is where Hot Spring differs from most brands. These tubs generally run more than one element, so a “filter change” is a set purchase rather than a single item. Counts differ by model: a Grandee is not a Jetsetter, and the same model changed over the years.

The useful shortcut is to read the compatibility list on the five-pack listing, which names Grandee from 1991, Envoy from 2004, Vanguard from 2001, Vista from 2004 to 2013 and the NXT versions from 2014, among others. Find your model and year there, then count what comes out of your own housing to confirm. Buying a four-pack for a tub that takes five is a frustrating way to discover the difference.

The cost question, done honestly

A full Tri-X set is the most expensive single filter purchase covered anywhere on this site. A pleated alternative that fits the same housings costs a fraction of it. Comparing those two numbers directly makes ceramic look absurd, and that comparison is wrong, because you are buying different things: one is a multi-year element, the other is a seasonal consumable.

Do the arithmetic over the period you expect to own the tub rather than at the checkout. Across several years of replacing pleated cartridges, the gap narrows considerably. It does not always close — that depends on how hard you run the tub and how diligent you are about cleaning — but it narrows enough that ceramic is a defensible choice rather than an indulgent one.

The case for the pleated alternative is behavioral, and it is a real case. If the price of a full ceramic set is the reason your filters have not been changed since 2023, a cheaper filter you actually replace puts cleaner water in your tub than an expensive one you keep deferring.

Cleaning a ceramic element

Rinse between soaks and clean properly on a schedule. The general method is in how to clean a hot tub filter, and what to soak in is covered in the best filter cleaners. Ceramic tolerates this treatment better than pleated media, which is the whole point of it.

Two cautions specific to ceramic. It is more brittle than plastic, so dropping an element on a concrete pad can crack it in a way a pleated cartridge would shrug off. And a long service life is not an infinite one: inspect for cracks and for a surface that stays discolored after cleaning, using the same judgment described in when to replace a hot tub filter.

The pleated alternatives, and their cross-references

Pleated filters in the Hot Spring pattern are sold under several names and print unusually complete cross-reference lists: Tri-X numbers 0969601, 71825, 79435, 73178, 73250 and 31489, plus Pleatco PWK30, Unicel C-6430 and Filbur FC-3915. One is listed at 20 micron filtration, which is a specification most cartridges in this category do not state at all.

Take the stated compatibility as a starting point rather than a guarantee. These listings generally note that manufacturer names are for reference only, which is standard aftermarket language and a fair warning. Measure your element and match dimensions, as on any filter matching job.

Filtration is not sanitation

Ceramic elements attract the idea that better filtration means less chemistry, so it is worth being explicit. A filter removes particles; it does not disinfect. Hot tub guidance is built around a measurable sanitizer residual at a controlled pH — pH 7.2 to 7.8, at least 3 ppm free chlorine or 4 to 8 ppm bromine.^{[source][source]} Those numbers do not change because you fitted a better filter.

On prices, and on what these scores are

Hot Spring filtration runs from inexpensive for a single pleated alternative to the most costly filter purchase on this site for a full ceramic set. Every button reads the live price where our price layer has one; anything we cannot verify, we do not print — the reasoning is on how we pick.

The scores are an editorial judgment of published compatibility, construction, stated part revisions and cost across a realistic service life, against our published method. We have not tested these filters, we make no performance claims on their behalf, and there is no rating markup in this page’s structured data.

The honest summary

If you plan to keep the tub and you will clean the elements properly, buy Tri-X in the pack size your model actually takes and treat it as a multi-year purchase. If the set price is what has been stopping you changing filters at all, buy the pleated alternative without guilt — the worst filter is the one still in the housing from three years ago.