I'm new to the world of hot tubs, I just picked up a used one. I understand the importance of clean filters and I'm wondering if they can be cleaned without buying specialty products that seem over-priced. Any household, or easily obtained, products that work just as well? I'd hate to spend $20 on a quart of SpaGuard Degreaser (I bought some, but with a bunch of other chemicals so I'm not sure how much it was), only to find bleach or something works just as well. Any thoughts with proven results?

Muriatic acid; (I'm cheap)

Opinions vary... but about a cup or two to 5 gals of water. Soak for 15 minutes or so. Rinse.

Keep unknowning people and animals away.

You may get some better opinions from others.

I'm with Pageup on this one. I've been using muratic acid (hydrochloric acid) for a few years now, both as a filter cleaner, and ph down. Never had any problems doing this. I usually go 1 part muratic acid to 4 parts water, and soak for an hour, but that is just what I do. Cleans very well, very cheap, and very redily available at home improvement centers and hardware stores.

BTW observe proper acid mixing techniques! ALWAYS ADD ACID TO THE WATER, NEVER ADD WATER TO THE ACID! (you can get splashes and thus burns on the skin)

Thanks guys. I actually already have muratic acid on hand (can't remember why), so I'll go that route. Thanks for taking the time to lend your advice and share your experience.

wow guys, just wow

do not, i repeat, do NOT soak your filter in muratic acid solution without degreasing it first. If you do, you will set oils into the filter making it impossible to get out, dont believe me, ive got the resource to back it up.

This excerpt is taken from a Unicel (manufacturer of replacement filters) guidebook circa 2006.

6. If the filter has a coating of algae, calcium carbonate
(residue from calcium hypochlorite), iron, or other
minerals, soak the cartridge in a solution of one part
muriatic acid to twenty parts water until all bubbling
stops. WARNING: Failure to remove all oils and
cleaning solution before acid soaking will result in a
permanent restriction of water flow and cause premature
cartridge failure.

Your filter cleaner (if its priced $ 20 its way too high) will remove oils and "organic contaniments" from the filter, soaking does a better job, only then do you want to use a muratic acid solution.

soaking in chlorine only breaks down algae and bacteria, not so much the oily stuff you really need to get out.

here is the my recommendations i printout with for people who request how to clean their filter

CLEANING FILTER – regular size:
Make a solution of 1 qt. Filter cleaner into 5 gallons of warm water, do not dilute more than this. Hose off filter, soak in solution 1-2 days, hose off filter again, and allow it to dry. DRYING is a big key to an effective cleaning.

Spec

Yeah but What brand/ingredients of 'FILTER CLEANER'?

It sounds like to me a good kitchen degreaser would help this... but of course that's a ridiculous assertion for me to make `using a standard kitchen soap`.

I mean, the question is... what's real and what ain't? There's a lot of overpriced crap on the market, and I hate paying 10 bucks for diluted dawn dishwashing liquid.

So what is it that works using your method?

Out of curiousity, I checked with the unicel website, and acording to that information, a mild acid soak is advisable after the initial cleaning proceedure, if calcium buildup is suspected. The initial cleaning proceedure is to first soak with a degreasing agent, rinse, then soak in the mild acid. One thing that does bother me is the Unicel site says a test of wether or not to use the acid soak, is to put several drops of undiluted acid directly on the filter media! Wait, question here... if a dilute solution is so bad, why the hel...ahem, heck would you put undilute acid on it at any point? BTW I never did find the section on the site stating that the acid will drive the "gunk" into the filter perminantly... The site mentions the tried and true method of how people washed D.E. grids (diatomacious earth grids). It cites that the reason those grids held up over pleated cartridge filters is due to the protective D.E. media that coats the grids. Personally I can't see this as being a valid statement, in that when you clean a D.E. filter grid, you remove all traces of D.E. media prior to the soak. Also, the acid soak for these filters is generally much stronger in concentration than the simple cartridge filter soak. I have a D.E. filter on my pool, so I know. I think what the site is saying is that the traditional soak of muratic acid on a pleated filter will have harmful effects, over time, but only in that many people may be using the stronger concentration as used for the D.E. filter. I also believe that the degreasing agent (as mentioned) may help dislodge some fatty solids from the filter, but in reality the spray down of the filter is what is doing most of the work. Perhaps I should elaborate on the cleaning procedure I STRONGLY recommend and live by: First (and this is true with ANY cleaning method) thoroughly spray the filter with plenty of water to remove any loose contaminates. This will dislodge any foreign particulate matter, including oils. Soak filter in the muratic acid and water solution Spray off filter as in the first step Reinstall and use as normal. FYI my filter is 3 years old, looks as good as new, works as good as new, and this is the only method I've ever used on it. Now, regarding the chlorine.... Chlorine will dissolve any organic compound if left to soak long enough. It is a base chemical (having a PH lower than 7). All base chemicals have the properties to dissolve organic compounds. Lye is Sodium Hypochlorite, and is essentially a super strong bleach, based on the same compund of chlorine. In the food industry it is used literally to dissolve remaining food particulate from machinery. Your crystal Drain-O is the same thing, for the same reason. That said, chlorine soaking will dissolve organic compunds from a filter, including organic oils. The problem is it won't actually clean the filter. Acids are used to dissolve petroleum or other non-organic compunds. Your driveway cleaner is acidic for this reason. Acids are also used for that purpose in the food industry for similar reasons. This points out that while filter cleaners (as stated for such purpose) claim that their product is best for cleaning filters, if a person looks at the acid content, they will see that the filter cleaner is based on acid. Acids and soaps (bases) are not compatible, will react to one another, and neutralize into simple salts in the end. For that reason you won't ever find a soapy filter cleaner. Man, I am really rambling on way too long on the science of this crap... take it from me, pageup, and others in the know and in the practice of use, that simple muratic acid will do the job nicely. " title="Surprised" />

Well this is one reason why I try to stay out of the chemistry forum. A sheitfest starts up too quickly. That said, I really would like to find something off the shelf - (that can do the job) without costing an arm and a leg, that's made for it. At the prices charged for most folks with simple inexpensive filters, it would be cheaper and easier to just throw away the filter and get a new one. They're cheap enough online. Note from the op:

I'll go back to snoozing now and forget I ever said anything... Lol. " title="Evil or Very Mad" />

I wholly agree with you Pageup...

I'll just keep soaking up my filter as i have for the past 3 years until it finally dies, then I will just buy another one.

You guys do the laundry? Bleach will make you tidy whities blinding bright, but also breaks down the fabric and shortens the life. Same thing with using concentrated chlorine or muriatic acid on filters. They're made of dacron, and both chlorine and muriatic acid will break down the fabric over time. Muriatc acid should be used if there's mineral deposits on the filter. But if there isn't (use the drop test to determin), it'll probably do more harm than good. If you're really hung up on having the filter bright white, go ahead with the chlorine, but understand it does shorten the life of the filter, and really only bleaches out the color of the staining (just like in the laundry). By the way, the filters will actually be more effective when a little dirty as the dirt reduces the size of the "holes" and will filter out smaller particles. For a CHEAP cleaner use trisodium phosphate (not the fake stuff only available in some states where TSP is banned). 1 cup per 5 gallons of water. Works as good if not better than any filter cleaner stuff. Unlike Pageup, I'm lazy.......... I rerely even clean my filter and just grab a new one off the shelf about every 6 months. " title="Laughing" />

One way to save money on filter cleaning chemical is to buy or make a filter cleaning flask. I purchased one online, but it would be easy enough to make your own. The one I bought is simply a 16 inch length of 6 inch diam. PVC pipe with a cap on one end. This way I only need about a gallon and a half of cleaning solution instead of 5 gallons. You can find several examples online by searching for "spa filter cleaning flask"

---

Did you not read all of my excerpt of 6: ?,
WARNING: Failure to remove all oils and
cleaning solution before acid soaking will result in a
permanent restriction of water flow and cause premature
cartridge failure.

---
Why even use any cleaning products for DE, its the DE that traps ths contaniments from the pool, hose that off and your done.

---
Thats like saying, if I use enough water, i can just rinse my laundry, never needing to use a detergent

---[Perhaps I should elaborate on the cleaning procedure I STRONGLY recommend and live by:

[First (and this is true with ANY cleaning method) thoroughly spray the filter with plenty of water to remove any loose contaminates. This will dislodge any foreign particulate matter, including oils.

Soak filter in the muratic acid and water solution

Spray off filter as in the first step]

Wish you had a cartridge filter, and i was the guy u were going to be buying filters off of, if you were, and i was, i'd see you about every 2-3 years or quicker than that.

---
again your using DE filter, not a cartridge, hose it off and your good as new.

[Now, regarding the chlorine....