Pot scrubbers have the best combination of biofiltration capability, ease of use and availability of any biomedia. Extensive testing has shown it to be a very good media to put in an aquarium filter. If one is a nerd like the author one might be interested in this long boring article on why this is true. It includes testing which proves this is true.
Pot Scrubbers in Depth
Pot scrubbers go by several names, including mesh scrubbers, pot scrubbies, plastic scourers and scouring pads (one actual description was “plastic pot round scrubber scouring pad plastic” LOL). And there are several other varieties of pot scrubbers given the same names. This makes shopping for this media a bit of a challenge. Amazon has them listed under “Assorted color round nylon fish scouring pads“ (24 pot scrubbers for $8).
I recommend buying pot scrubbers at the local Dollar Store (if you can find them). A comment to this website on Amazon pot scrubbers is pertinent:
“Sadly, Pot scrubber from amazon quality is down the hill recently. Not only it become way smaller (compare to 3 years ago), it also have bigger holes and less density. It is less weaved and it break down in a week even using for cleaning dishes. the plastic break so easily. It is cheaper but quality got worse. If buying from amazon read recent reviews, you can see it is poorly made now”
A surface area for pot scrubbers calculated was based on simple math calculations by a reader.
“I did a little checking, tore apart a pot scrubber measured the width of the strand at 1mm wide. Placed the unrolled scrubber over a 3″ pvc and pulled 8 meters of strand from 10 rows of stitching. Counted 140 to 150 rows of stitching on a couple of scrubbers. So 800 mm per row of stitching with 2 sides of the material that’s 1600 mm sq area per row x145 rows average. That’s 232,000 sq mm area per scrubber, convert that to sq ft 2.49 square ft per scrubber.. round out a bit that’s 50 pot scrubbers per pound of fish metabolic weight with a bit of wiggle room. I picked up 7 packs of 7 scrubbers at the dollar store for under 10 bucks. Cheapest filter media ever made. Also, the material is 100% nylon.”
Types of Pot Scrubbers
There are several types of “pot scrubbers”:
1, There are the non-woven rectangular pads of thin plastic fibers about 5 thousands-of-an-inch in diameter. These are typically dingy green in color. These can be used to replace cartridges in cartridge type mechanical filters but they are not useful as a biofilter media.
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2, Then there is a softer “natural” sponge on it, with holes that are of many sizes and shapes, generally bonded to one of the pads above. This is a cellulose product which will disintegrate in weeks in an aquarium. Avoid them.
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3, Then there are urethane foam and melamine foam (“Magic Eraser”) pot scrubbers. These have too small of a pore size and do not work well as filter media.
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4, Then there is the “plastic pot scrubber”. These are like a doughnut shaped ball of thick plastic fibers about 30 thousands-of-an-inch in diameter. These are brightly colored in lots of shades. This is useful for filtration and is what we are talking about in this article.
The latest price as of December 2021 is 24 pot scrubbers for $8 on Amazon listed under “Assorted color round nylon fish scouring pads “. But note with COVID the price and availability are fluctuating wildly.
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Calculating the Number of Pot Scrubbers Needed
A question and answer from the comments section of this website will be instructive here:
Question:
“I would like to get the Eheim 2260, which has 18 liters room for media. After reading your filter media comparison test articles, I intend to fill this thing up with pot scrubbers, as the price/performance ratio is unbeatable.
I have no idea on how many average sized scrubbies would fit in such a volume (tightly packed too). You have a lot of experience with this kind of media, could you please provide me with an estimation?”
Answer:
“OK 30 small (2.5 inch by 1 inch) pot scrubbers are now for sale on Amazon at $18. There is roughly 8.7 small pot scrubbers per liter. Or you will need about 150 (8.7 x 18) small pot scrubbers, 5 packages or $90 worth of small pot scrubbers.”
This is the result:
Pretty darn good calculations! 150 calculated versus 154 actual!
The data which gave this number is as follows
30 small pot scrubbers from Amazon (2.5 inches in diameter, 1 inch thick. 4.9 cubic inches) filled a box with the dimensions 3.5 inch by 5.5 inch by 11 inches. This is 212 cubic inches, or seven cubic inches per pot scrubber. This means 30% of the box is free space between the scrubbers. This works out to be $0.086 per cubic inch or $0.60 per pot scrubber.
- one liter is 9 pot scrubbers at $5.24
- one gallon is 33 pot scrubbers at $19.87
- one cubic foot is 247 pot scrubbers at $148.20
But there has to be a caution here. Some of these pot scrubbers are four inches in diameter and one inch in thickness. And some of plastic pot scrubbers (like the ones from Amazon above) are about two and a half inches in diameter and an inch in thickness. The four inch pot scrubbers have a volume 2.5 times that of the small pot scrubbers. If you buy the four inch ones the numbers above need to be changed to
- one liter is 4 pot scrubbers
- one gallon is 13 pot scrubbers
- one cubic foot is 95 pot scrubbers
This is a BIG difference! Also note that the price also varies a huge amount by country. In some countries plastic pot scrubbers are very cheap and in others very expensive.
Comparative Costs
There is a problem with plastic pot scrubbers as far as cost in the USA. I cannot find a bulk supplier that will sell more than 30 pots scrubbers at a time for roughly $20 for one gallon. There thus is no huge savings to be had by buying in bulk. If you have a large filter this can be a problem.
The K1 media, which has very close to the same performance, is $25 if you buy one gallon, $55 if you buy one cubic foot (that is $7.33 per gallon). On eBay you can buy 2 cubic feet of K1 media for $70. That is $4.67 per gallon or $1.24 per liter when you buy K1 in bulk of two cubic feet.
So if one has a single small canister with only one gallon of capacity, buying the pot scrubbers makes sense. But remember, this hobby is addictive. Invariably you will be getting larger and larger tanks and more and more filters. So buying two cubic feet of K1 type media and filling the small canister with that, also makes a lot of sense.
Testing Pot Scrubbers
In a test of ammonia oxidizing capacity of various filter media under actual aquarium condition plastic pot scrubbers performed extremely well. They outperformed K1 media and were some five times better than lava rock or ceramic rings. So this is an excellent media for all submerged media filters. This was quite surprising as the surface calculations for pot scrubbers said they were not all that good.
A test of ammonia oxidizing capability of various filter media was run. The first number, the “efficiency” is the average ammonia oxidizing that 15 cubic inches of media accomplished over a 90-day period. The second number is the “effective” surface area in square feet per cubic feet calculated from that test. The third number is the effective surface area in square feet per cubic feet calculated by simple mathematics. The correlation between the test results and the calculated surface area is very significant and means the testing was accurate.
The higher the numbers here the better the media. The plastic pot scrubbers did surprisingly well in the test. In all probability this was due to their porosity. Pot scrubbers have a very porous structure which allows the rapid flow of water through them. This porosity also allows brown gunk to build up in the spaces. Brown gunk has a very large effective surface area. Plastic pot scrubbers are an excellent media for canisters and sumps.
Static K1 media is probably equal to the pot scrubbers in function but it is only inexpensive in bulk quantities of cubic feet. Since 30 ppi foam can be expensive (Poret isn’t cheap), has to be very carefully cut to minimize flow around and because 30 ppi foam will plug up in some situations, pot scrubbers are probably the best all around media out there for small filters. In larger filters the K1 begins to have a decided cost advantage because it is cheaper in bulk.
A pot scrubber gives equal filtration in both a large and a small filter. One might have to cut up the pot scrubbers for a small filter but that does not change their efficiency. The open volume is about 80%. Now if the flow is low then pot scrubbers will fill with brown gunk. And brown gunk has surface area, which is good. If the flow is fast, little brown gunk will form but the biofilm which is there is more efficient. So you have two competing things going on. So predicting the performance in any given situation is not exactly an exact science.
KaveMan Aquatics
Kev at Kaveman Aquatics YouTube channel recently did a video where he replaced all the ceramic media in the baskets in his canister filter with pot scrubbers for three months. After three months the water to his heavily stocked aquarium had changed from “dull” to “crystal clear”. Others have sent comments to this website where they replaced all their expensive “stuff” with pot scrubbers and got excellent results. It is all anecdotal and I generally avoid anecdotal but someone might be interested.
An Important Caveat
There is one problem with pot scrubbers. They are made of polyethylene plastic and are very open in their structure. Polyethylene is very lubricous and few things stick to it. So if one holds a pot scrubber under running water or vigorously swishes it back and forth in a bucket, virtually all the beneficial bacteria will be swept out of the structure.
In all but very heavily stocked tanks pot scrubbers should never need to be cleaned. If they become so plugged up that flow is obviously around them and not through them one can lightly clean then in a bucket with a few squeezes’ to each pad.
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Dave says
In reply to Sam I’m not familiar with “bog filters”. I would add an air lift tube with an air stone in order to get water movement through the media.
Sam says
Hi Dave,
Firstly, I want to extend my deepest thanks for the information you have provided on this site. The constant refrain of “100gal minimum” for goldfish that seems to have spread from PETA to nearly everyone in and outside of the hobby had me questioning my sanity and logic. Your articles were a major breath of fresh air!
I am planning on building a container pond with a 27gal tote using a 5gal trash bin as a bog filter. I’d like to stock 3 Sarasa and some rosy reds if possible. My idea was a few inches of void space for settling solids, followed by about 1cuft of pot scrubbers or k1, topped with gravel for plants. I’ll use something sturdy and porous to support the gravel layer and plumb a drain at the bottom for back flushing if the need arises.
Any issues you can see with this?
Thanks again for bringing real logic and science to this field!
Dave says
Stuff as many pot scrubbers in as you can. The more the better.
Milky water 😔 says
is it possible that my aquarium water is not clear because i jammed all of my pot scrubbers to my diy canister filter? when i open the canister the lid kinda pop out a bit (i guess i put too much pot scrubbers). the filter is 4 months old and the flow is about 1.5. should i put less pot scrubbers in it? does putting too much pot scrubbers give diminishing return?
Jim says
I’ve been using pot scrubbers and Matrix in my FX canisters.
Amazon currently has 100 3.1 inch pot scrubbers that for $23.49 (ASIN B0B28W8L85) which is a bit cheaper. A package of 30 is about $15 from a different manufacturer.
Getting ready to gradually swap out all of the Matrix for more pot scrubbers after reading through this. Thanks!
Dave says
In reply to Woody …. More efficient when completely submerged. Wet dry and trickle filters are not good filters,
Woody says
Are pot scrubbers more efficient when completely submerged in water or as a wet/dry combination?
Dave says
In reply to Tim …… The foam that comes with the unit is the best media, leave all of it in place. Replace the ceramic rings with either plastic pot scrubbers or K1 media (pot scrubbers will be much cheaper in this size filter). And surprisingly the layout makes little or no difference to the efficiency. Just fill and stack the three trays Willi nielli
Tim says
Hi David – we have a small aquarium that I would like to switch from a hob filter to a cannister setup. Based on the manufacturers specifications, it looks like the Fluval 207 would be a good option. Could pot scrubbers be used as media in this type of filter? If so, how would you recommend laying them out? – Many thanks, Tim
Dave says
In reply to Paul …. Simply do the switchover, then do a fish in cycle. Easy. And if you are going over to gravel I would add an undergravel filter. Hang on backs, even with pot scrubbers and foam, are simply not that good of a filter.
Paul Terranova says
I have had aquariums all my life I always just set it up with what came with it . Now I found your website and realized I have alot wrong. I have manufacturers cartridges in hob filter and want pot scrubbers and 30 ppi sponge. I also have pea gravel and want regular aquarium gravel. So my questions are those 2 things enough media in filter ? And my tank has been running for 8 months and I took 2 plus months for cycling and water parameters are perfect except for slightly cloudy all the time fyi I know why now. How do I change everything over without screwing up tank and killing fish . I was also lead to believe to plant heavy but I can deal with that. Please help
Dave says
In reply to Bee ….. Simply replace the 30 ppi foam with as many pot scrubbers as you can jam in. Leave everything else exactly as recommended by Oase.
Bee says
I am preparing to change out my canister filter for my 55 g. I will be installing an Oase BioMaster 250. There is a pre-filter that can be pulled out of the top with sponges covering it for quick cleaning, and inside has 4 baskets. It has some K1 media in lower, and 2 baskets of 20ppi foam, then top basket with thin 30ppi foam. I would like to embrace the pot scrubbers. What would you suggest for the four baskets (and what order). Also, what should be done with the pre-filter, if anything?
A. says
thanks you so much for the reply. I am a slightly researched newbie, whom questions everything and then gets overwhelmed. haha Your article was greatly appreciated and I look forward to diy-ing a filteration that maintains bacteria better then a throw away cartridge. (I’ve only started with a 20 Gallon, so seeing the big buckets of pot scrubbers was quite impressive!!!)
Dave says
In reply to A …. They would work but the sponges are very small and expensive. Poret urethane foam is a much better option. They also make a stainless steel pot scrubber that works great but is expensive.
A. says
would a silicon based pot scrubber be a viable option ….last longer? Has anyone tried them?
https://www.amazon.ca/Silicone-Scrubber-Reusable-Scrubbing-Cleaning/dp/B089VXWSMW/ref=asc_df_B089VXWSMW/?tag=googleshopc0c-20&linkCode=df0&hvadid=682852646141&hvpos=&hvnetw=g&hvrand=17916933859952445855&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001052&hvtargid=pla-1635480392615&psc=1&mcid=cc7b720ec1343fde864f7cecde25c8eb&gad_source=1
Dave says
In reply to George …. The plastic is just fine. Go for it!
George says
Thanks a lot David for your article
I use an eheim 2224 2 baskets 1.5 liter each of room and I am planning to get rid of matrix and ceramic rings and replace them with k1 media from Evolution Aqua ( surprisingly are available in Greece) running static and the other basket with pot scrubbers is there any material specification that I should check ?
I discover 24pcs for 6 usd from aliexpress and they claim material plastic is it ok ?
https://www.aliexpress.com/item/1005003638316148.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.2.3f18PQscPQsc0q&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=e8029e60-054b-46af-8e2a-6a695c72f3a0&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:e8029e60-054b-46af-8e2a-6a695c72f3a0,tpp_buckets:668%232846%238113%231998&pdp_npi=4%40dis%21EUR%215.65%215.65%21%21%215.99%215.99%21%402103080b17160486264686338ec165%2112000026599818167%21rec%21GR%212608285078%21&utparam-url=scene%3ApcDetailTopMoreOtherSeller%7Cquery_from%3A
Thanks regards George
Dave says
In reply to Tyler … The strands of plastic in these bigger balls appear to be much larger than the strands in the pot scrubbers (MUCH LARGER). This can be expected to severely limit the usefulness of this media.
Tyler says
I just found these “Bacti-twist” balls and they look like they could be a cost effective alternative to the pot scrubbers. $32 each for 1 cubic foot, $26 each if you get two or more. They appear to be the same material, just in one ball.
I keep having little 1/4″ scraps come off my pot scrubbers and start swirling around my tank, so I’m trying to find something else to use on a larger tank I’m getting set up and to upgrade the filtration on my pond.
What do you think?
https://www.thepondguy.com/product/bacti-twist-biological-mechanical-filter-media/?sku=110200&p=PPCGOOGA&gad_source=1&gclid=CjwKCAjw5v2wBhBrEiwAXDDoJRGTy2wHTKvqZvzQZ6c4tJeCEZVs5QDuJQQkoX2SvqRIxbO6bf7DGBoC7rQQAvD_BwE
Dave says
In reply to Tine ….Just buy the K1 type media or 30 ppi foam.
Tine says
Hi. We don’t have pot scrubbers in Norway, but we have those body-washers witch looks like a loosly scrunched up pot scrubber. Do you think it’s a good substitute or should I just buy the K1? I only have a Eheim classic 250, so I don’t need a large amount. Best
Dave says
In reply to Robin … Replace both of the ceramic media with pot scrubbers over a three week period. Other than that just keep doing what you have been doing.
Robin Beasley says
Can Pot Scrubbers be used in Generic HOB filters that didn’t even come with those flimsy filter pads you are supposed to replace every week? Right now, I have a sponge of unknown PPI in the bottom of the HOB tank and then ceramic rings and ceramic porous media (looks like coral but isn’t) on top of the sponge. I also have a sponge of unknown PPI over the intake tube as my first line of defense and to keep babies and shrimp from getting sucked in. I love the idea of using the pot scrubbers especially if they are from recycled ocean plastic but if they above set up is good, I will keep it. BTW, I have a LOT of brown gunk but the only sponge I ever clean is the intake tube sponge. It gets clogged up about once a month with plant material and fish crap, etc. so I clean it really well then replace it and keep going. I am just wondering if the scrubbers might not be the better way to go.
Dave says
In reply to Jimmy ….. NO i would say the sponge filter will be better.
Jimmy says
Would an air pump driven box filter filled with pot scrubbers work better than a sponge filter?
Dave says
In reply to anonymous …… Pot scrubbers should only be cleaned lightly when they get really plugged up and gross. Personally I use a lot of pot scrubbers and they only get lightly cleaned every few years, if then.
Anonymous says
a question about cleaning pot scrubbers – is cleaning them necessary if flow through the filter is unaffected?
Dave says
In reply to Keven … Skip the lava rock. Go with 100% stationary K1 media. A 55 gallon drum is a LOT of media and K1 is much cheaper in bulk than pot scrubbers and almost as effective.
keven garrard says
David, thanks for the article, it helped a great deal. I have a small pond and a 55 gallon barrel. I had lave rock at the bottom and the course and fine media pads, the fine did not hold up so well. So I am moving on to the scrubber pads, I am relatively new to this and I see how complex some guys systems are, me not so much. I am wondering should I put the lave rock back in the bottom, or just go with the pads only? And instead of just filling the barrel, I thought to put the pads in a laundry basket. I am kinda redoing my barrel as I discovered the flush bulk head was not as secure as I would have liked, every time I get to a certain point it seems I learn something new, read forgot or did not know. Last thought, can K1 media and scrubber be combined? Just seems like a better option. Any helpful comment is greatly appreciated, thank you very much for your time.