I have an above-ground fiberglass spa in the backyard of my home. I'd call it a four-person as more than that would probably overflow the tub, but it's got seating for up to seven; my best guess as to water capacity is about 350-400 gallons.

The spa's circulation system is a combination electric pump/electric heater, which is upstream of and inline with a Hayward cylinder filter and housing. We bought a brand-new filter for it when we bought the house, as a part of the general process of making the spa usable again (it had been neglected for at least the previous winter). The filter's about a foot wide by a foot and a half tall; at least half the size of the smallest comparable Hayward filters that the HIWs and Leslie Pools keep in stock, and possibly smaller.

When the filter is new, newly-cleaned, or even taken out and air-dried for a few hours, the jets run great. However, after a period of just a few days of normal circulation with the jets "off", the water flow drops to next to nothing. From week to week the situation becomes so bad that there isn't enough pressure to siphon air from the intakes into the jets when the pump's at full (and so you don't get much massaging action; not much fun).

The circulation system is very simple; skimmer and bottom drain -> gate valve -> pump/heater -> filter -> gate valve -> jets. The two gate valves basically allow you to hold the water in the tub while you work on the pump or filter. There's no backwash capability, and there's really no good way to even fully drain the tub. This, along with a host of other little things (like, I dunno, the spa no longer being level because it didn't have a proper foundation) makes me think that some things were skipped in the installation.

Currently, the workaround when the flow is too low for a dip is to take out the filter. This isn't a great solution because the filter housing is not easy to get to with bare feet, and if we let it go then obviously the water isn't being filtered and turns cloudy and green. To clean the filter, I remove it, rinse it off well, then soak it in filter cleaner, rinse well again, and reinstall it. This works for a week and then I have to repeat the whole process, which adds up to two hours to the regular spa maintenance that otherwise takes less than a half an hour (skim, brush, net, test, balance, shock, new chlorine tab, test again).

Is there a problem here? I think so. I think either the pump isn't strong enough to get good flow unless the filter is completely clean, or the filter is too small and is gunking up too quickly. There could be something else; I doubt it's bio-slime as the stuff I use for shock is also an algaecide and it does a good job. Maybe too much clarifier (the shock has that in it too)?


  • Suck it up. Maybe the filter really does need to be rinsed out weekly; the FAQ from one of the comments says to rinse "periodically" and to only chemically clean the filter once a season or so (every time you need to drain/refill the tub).
  • Replace the pump with a higher-pressure one for better flow no matter the filter state.
  • Replace the filter housing with one that has more filter area in the cartridge so it'll go longer before gunking up completely.
  • Redo the circulation lines to add backwash and/or bypass capabilities, allowing for a more automated clean-out and/or the ability to easily ignore the problem while in the tub (even clogged, the filter does a great job keeping the water clean, it just doesn't allow enough circulation when we want the jets on full).
  • Look at the products I'm using and see if any are contributing to the problem (adding too much hardness, too much clarifier compound, etc etc etc)
  • Drain, clean, refill tub (the water's perfect according to the last test strip; maybe a bit high on the pH)
  • Rip the whole spa out and start over (may sound extreme but there are reasons)

Pics when I can get them.

  • 3
    When you remove the filter to clean it, what does it look like? A picture may be worth a thousand words here. Is it caked up or visibly clogged with something? Is it kept covered when not in use to keep any airborne debris out of it? Is your yard enclosed to keep critters out?
    – ShoeMaker
    Commented Apr 30, 2012 at 20:26
  • The spa has a cover and I'm reasonably sure nothing's taking a dip in it when we're not around (both our dogs are scared of deep water, and are more interested in trying to dig out of the backyard). When I remove the filter it looks gray, sometimes tinted green or yellow depending on the season and how long I've let it go, but it doesn't look particularly "caked". Giving it an up-close rinse with the hose brightens it back to almost-white except right at the folds and at the top and bottom ends. The filter cleaner helps in those areas but of course it never quite gets back to "new".
    – KeithS
    Commented Apr 30, 2012 at 20:33
  • Spas are very touchy when it comes to PH balances and cleansing, have a look at this troubleshooting guide. I think that it is mostly a matter of finding the correct balance for your system and climate.
    – ShoeMaker
    Commented Apr 30, 2012 at 20:43
  • 1
    I think you're way over-thinking things. The filter is clogging. The fix is to figure out what is clogging it. Sounds like you have icky stuff (technical term) living in the guts of the system that you need to kill off.
    – DA01
    Commented Apr 30, 2012 at 21:05
  • 1
    @DA01: when reconditioning the water after letting it go over the winter, I accidentally put something like 30 times the recommended amount of shock into the water (I misread the fine print; I was used to a product that gave you an amount to add for each 500 gallons, but this stuff was calibrated for 10,000 gals). I'm pretty sure any life in that spa water was quickly extinguished; inside of 30 mins the water went from slightly green and cloudy to pristine clear blue (and probably would have caused severe chemical burns).
    – KeithS
    Commented Apr 30, 2012 at 21:26

2 Answers 2


I don't know if this is really an answer, but I've had a Coleman 6 person spa in service for about 25 years. Yes, 25 years! I have never had the same problems you are experiencing. We learned early on that any clothing (bathing suits etc) must be very clean and rinsed extremely well before going into the spa. Clothes cleaning detergents left in the fabrics release into the pool water and cause foam quickly. The clarifier is good at flocking these soaps, but they do tend to gum up the works quickly. We never lost a lot of pressure however, just had to clean the filter. We also made a habit of completely changing the water at least twice a year. After draining as much as we could via the drain hose, we used a wet vac to get as much out of any low spots. We then put in just enough water to cover the intake close to the bottom and jogged the pump to cycle clean water through the system and get the dirty water out. Again, drain and vacuum and repeat this process until the water looks clear. We do this with the filter out. This will clean out a lot of crap. About once a year just before we do a drain and complete cleaning, we treat the tub with anti-scale cleanser. This cleans the internal pipes of built up scale and solids. In your case, you may want to do this anti-scale treatment for a few days with the circulator on low and the filter out to purge the internal system. Then go ahead and change the water.

Another test you can do is to see how well the pump pushes water. When you have the small amount in the bottom, just above the intake, jets exposed, turn the jets to full, air off and see if the pump will shoot the water out of the jets with extreme force. Mine will shot water 20 feet away!!!! lol. If you don't have really good pressure, you may have a warn pump impeller. They can be damaged over time by chlorine based sanitizer, I never use chlorine, just bromine based shock etc.

The other item to check is if you have the right filter for your unit. Filters come in so many styles and densities. You may need to find one that allows better flow.

Assuming you find the root cause of your problem, good housekeeping, keeping as much contaminates as possible out of your tub will help. Very clean bathing suits or none at all,(yahoo) no body cosmetics such as body oils, moisturizers, perfumes etc. Keep chemical treatments to a minimum. Do a quick check weekly for PH, Total alkalinity, and bromine level. Adjust them sparingly so not to overdo any chemicals. Once you get everything under control, maintaining it is very easy and quick. Good Luck


The filter is the issue. Might be the wrong size (too many pleats). Filters are sold in square foot options. check out http://www.hottubworks.com/ buy a filter with less pleats/square footage. Good tech support as well.

OR it's the water. Calcium will do it. You would see it in the filter when cleaning as white chalky material.

  • 1
    Less square footage? Seems to me I'd want more square footage, so there are more spaces in the filter to fill with gunk before overall water flow is affected. I agree with the calcium diagnosis; here in Texas there's a LOT of limestone and so we get pretty hard water.
    – KeithS
    Commented May 2, 2012 at 20:36
  • A 1-comment user with an answer suspiciously involving the store URL for a fairly general and widespread category of product? Does that kind of obvious spam not get cleaned away here? Not just being rhetorical, I don't know/remember...every stack having different rules and philosophies gets confusing ^^;; Commented May 22, 2017 at 11:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.