Hot Tub Filter Cleaning Questions.....frequency and best method to clean?

duganderson

Well-known member
Jan 26, 2021
92
Minneapolis
I have a 2005 Marquis 400 G. hot tube with two filters.

The manual says to clean the filters every month. Would you clean them more often than this?

What is the best method to clean filters? What cleaning products do you recommend?

Thanks, Doug
 
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5tan

Active member
Jan 9, 2021
37
Canada
Pool Size
1643
Chlorine
Liquid Chlorine
I have 2 coreless filters in my Bullfrog A7. The touchscreen and app prompts me to "Rinse filter with hose" every 30 days and "Clean filter in solution" every 60 days. My water is crystal clear and needs nothing except for 150mL chlorine after each soak (every 3 days) and ~40g dry acid every 2-3 weeks.

Usage is 2 persons, 3 times a week, 2 hours per soak = 12 person-hours per week. Filtration+ozonation set to 0.5 hours once every day, and filtration+ozonation also runs during heating cycles (which is 3-6 hours before soak time).

The higher your person-hours of usage per week, the more frequent you will need to clean your filters. It also depends on the filter capacity, in terms of how much dirt it can hold before it either clogs or starts releasing it back into the water.

I use the Mikise PowerPic Reach (MIKISE | POWER PIC REACH | Ultimate Filter Cleaning Tools) first to blast the dirt from the inside out.

Then I use the Mikise Filter Flosser (MIKISE | FILTER FLOSSER | Ultimate Filter Cleaning Tools) to spray the filter from the top of the pleats down through bottom. Other similar filter tools are plastic instead of metal, with plastic prongs that stick in between the pleats. These deeper prongs may or may not work better, I haven't tried.

These 2 Mikise tools are all metal and built very well, expecting them to last 10-20 years if not more. The plastic tools seemed like they would have a short life and not survive an accidental drop, so I didn't bother trying based on their plastic construction.

After pressure washing with these 2 Mikise tools, I soak the 2 filters in their own buckets that are small enough such that the filters sit in the buckets with minimal space to spare on the top and edges. I then add filter cleaning solution according to the bottle's dlution ratio, spin the filters around so the solution is thoroughly mixed, set a filled glass jar on top to keep the filters submerged, then leave them overnight. Next day, rinse the filters thoroughly, and reinstall while wet.

Some people recommend drying the filters before reinstallation, but no one has provided me any real logic or science behind it, or even a spa manufacturer or filter manufacturer recommendation. Unless the filters are brand new on the store shelf, filters are always wet no matter what, whether they are in the spa, being rinsed, or being soaked in solution. When other paper media gets wet and dries, its fiber structure deteriorates due to microfolds and microcreases developing inside the media as it dries, and the paper also shrinks and pulls away from glued/bound edges. Can't say if the spa filter media reacts the same, but we do know that these filters in their natural state are completely wet and immersed for weeks/months at a time, so I don't see any reason to change that.
 

A.O.

Well-known member
Apr 12, 2016
310
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
A lot depends on bather load, just a couple adults or a bunch of kids too? Here its just me and the wife, I hose mine off about every month or so, I keep two filters, pull one out, put the other clean one in, clean the one that just came out of the tub and let it dry and be ready for next time. If one seems dirty or discolored I will give it a soak in filter cleaning solution but normally just hose them off good. No need to overthink it all or buy lots of gadgets to do it...
 
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Newdude

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TFP Guide
Jun 16, 2019
8,783
NY
*disclaimer that I found this out after selling my hot tub and never tried it.

I read that the dishwasher works awesome for hot tub filters. If you think it through, dish detergent is designed to remove grease/grime/oils and is almost perfect for what you need. So on paper it totally checks out.

next time you need a new one, give it a try. It either works great or you were replacing it anyway. :)
 
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A.O.

Well-known member
Apr 12, 2016
310
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
*disclaimer that I found this out after selling my hot tub and never tried it.

I read that the dishwasher works awesome for hot tub filters. If you think it through, dish detergent is designed to remove grease/grime/oils and is almost perfect for what you need. So on paper it totally checks out.

next time you need a new one, give it a try. It either works great or you were replacing it anyway. :)
Agreed! I used dishwasher detergent for years, like you said, cuts through grease/grime/oils and doesn't suds up, never had a problem with it.
 
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5tan

Active member
Jan 9, 2021
37
Canada
Pool Size
1643
Chlorine
Liquid Chlorine
The reason for using the tools I mentioned above is to use pressurized streams of water on normal household tap pressure to blast out hair, dead skin, bits of pipe glue, grit, etc from the very deep filter pleats. A good hose with a non-aerated high pressure stream can do the job 80-95% of the way, whereas these specific tools will get you to a 99% clean. If you don't have a particularly high attention to detail, following the spa and filter manufacturer's recommendations of just hosing off the filter will work just fine. But if you stick your face in there and look inside the pleats, you'll find stuff that a hose can't get.

A dishwasher will definitely not be able to clean throughly because the pleats are deep and the end caps are usually not removable. All the crud will accumulate inside the pleats and on the end caps, so you'll be left with squeaky clean hair and chunks of dead skin still stuck in your filter, and probably a fair amount will be scattered all over your dishwasher too.

Filter cleaning chemicals are formulated to remove both mineral deposits incl calcium (via a strong acid) AND also degrease (via an alcohol solvent base). Bullfrog's Owner's Manual states that it is very important to remove debris and to use a filter degreaser before removing mineral/calcium deposits using an acidic product. I'm sure there's a good reason to do it in that order, but most hardware store spa filter cleaners contain both degreasing alcohol solvents and an acid all in one.

Relevant reading material:

As one of these links say, dishwasher detergent is formulated for hard metals, plastics, and ceramics - not for paper or polyester filter media, so it can be used in a pinch, but it likely too aggressive for paper/polyester media. Bleach in a concentration used for cleaning is also highly likely to weaken the filtration material.

My recommendation: use the tools and chemicals custom-designed, purpose-built, application-specific for cleaning spa filters, meaning they clean effectively, prolong the life of the filtration media, and don't cause the filtration media to either break down prematurely or to become ineffective at filtering.
 

Newdude

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TFP Guide
Jun 16, 2019
8,783
NY
Owner's Manual states that it is very important to remove debris and to use a filter degreaser before removing mineral/calcium deposits using an acidic product
Ok so what about treating them like mini cartridge filters ? Hose them off then do a 24 hour soak in 50:1 TSP followed by a 50:1 MA bath if still needed ?
 

5tan

Active member
Jan 9, 2021
37
Canada
Pool Size
1643
Chlorine
Liquid Chlorine
Ok so what about treating them like mini cartridge filters ? Hose them off then do a 24 hour soak in 50:1 TSP followed by a 50:1 MA bath if still needed ?
Yes, that is precisely what I would do. Hose off, then soak in a filter degreaser (I would prefer an environmentally-friendly, phosphate-free degreasing agent), then if I needed to remove calcium deposits, use a 1:10 MA:water solution (this 1:10 ratio comes from page 40 of the 2021 Bullfrog Owner's Manual. They don't specify the MA strength, so it is likely 15% or 30%, so maybe start with 1:20 ratio first if you are using full-strength MA).
 
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Newdude

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Filter cleaning chemicals are formulated to remove both mineral deposits incl calcium (via a strong acid) AND also degrease (via an alcohol solvent base). Bullfrog's Owner's Manual states that it is very important
So I have to mention this too. I put very little stock in what manufactures say. They devote millions upon millions into undoing what worked great forever to make repeat customers with expensive fixes to what didn’t need fixing.

Chlorox says my $2 toilet brush is no good. So I need to buy the cool looking one with one shot disposable pads that are 6 for $17.

Samsung says the water filter in my fridge can only be bought from them for $65 when HomeDepot HDX ones are 1/3 that, and 1/3 of THAT on Amazon.

Dodge says I can only use Penziol Platinum Ultra XYZLMnOP Premium synthetic oil in my V8 when there are many other synthetics that fully pass SAE certifications.

Mineral system manufacturers say that my pool will be easy and clear if I replace the expensive proprietary cartridges that cost many times more than bleach.

I can go on and on and on. I’m sure Bullfrog wants me to buy all their specially formulated stuff too.
 
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Newdude

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Jun 16, 2019
8,783
NY
use a 1:10 MA:water solution (this 1:10 ratio comes from page 40 of the 2021 Bullfrog Owner's Manual. They don't specify the MA strength, so it is likely 15% or 30%, so maybe start with 1:20 ratio first if you are using full-strength MA).
I chose 50:1 inadvertently per my PB advice originally. He told me to fill a big bucket and add a gallon of MA and let them soak for 24 hours. The big green landscapers bucket was 60 ish gallons minus the filters and add the gallon of MA and it was 50ish to 1. I believe the lesser strength was to allow the longer soak time. Anywho it worked awesome and I never looked back. I’d do it with hot tub filters in a heartbeat.

But I learned here to to the TSP bath first or risk certain metals/oils welding themselves inside the filters. (y)
 

5tan

Active member
Jan 9, 2021
37
Canada
Pool Size
1643
Chlorine
Liquid Chlorine
Agree, just use common sense and know what you're getting in to. You don't need Pennzoil Platinum Full Synthetic or Mobil 1 or any other particular brand name, but you do need API SN (or higher) or ILSAC GF5 (or higher), and in the exact SAE oil weight specified by the manufacturer. The international specifications/standards like API, ILSAC, and SAE follow strict testing, accreditation, and certification procedures in accordance with ISO and ASTM standards. The name of the oil brand and their trademarks do not follow any of those.

Bullfrog does not sell chemicals nor does the Owner's Manual mention any brand names for any chemicals. This isn't a branding issue, it's a standards/specifications/formulation issue and just a matter of using the right tools for the job. I buy my spa-related chemicals and items from a variety of sources: Canadian Tire, Home Depot, a local spa dealer, and various Internet sources. My big jug of dry acid is pH reducer "made for pools", because this jug was much, much cheaper than the same stuff by the same company in a smaller bottle "made for spas". Don't care about the brand names, I look at chemical composition and MSDS sheets.

I was only saying that Bullfrog advises/warns to remove grease and dirt prior to using an acid-based product. No brand names or trademarks are mentioned in the manual. I suspect there is at least some semblance of a chemical, physical science rationale for this advisement/warning.
 
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A.O.

Well-known member
Apr 12, 2016
310
Kershaw, South Carolina
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
So I have to mention this too. I put very little stock in what manufactures say. They devote millions upon millions into undoing what worked great forever to make repeat customers with expensive fixes to what didn’t need fixing.

Chlorox says my $2 toilet brush is no good. So I need to buy the cool looking one with one shot disposable pads that are 6 for $17.

Samsung says the water filter in my fridge can only be bought from them for $65 when HomeDepot HDX ones are 1/3 that, and 1/3 of THAT on Amazon.

Dodge says I can only use Penziol Platinum Ultra XYZLMnOP Premium synthetic oil in my V8 when there are many other synthetics that fully pass ASE certifications.

Mineral system manufacturers say that my pool will be easy and clear if I replace the expensive proprietary cartridges that cost many times more than bleach.

I can go on and on and on. I’m sure Bullfrog wants me to buy all their specially formulated stuff too.
Boy you hit the proverbial nail on the head there!!
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
8,783
NY
I was only saying that Bullfrog advises/warns to remove grease and dirt prior to using an acid-based product
Apologies to them and you. It sounded like they were preaching what *every other manufacturer out there* was. :ROFLMAO:
 
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