Poly / Polishing Pad Filter Media Mod for Spec Aquariums

The stock filter for the Fluval Spec series of aquariums are generally . . . OK. They perform their intended function adequately, but where they fall a bit short is getting that crystal clear water quality that we all want in our tanks.  I recently came across a great set of filtration products a few months ago and they have proven to be a very effective, easy to install, and have made a dramatic improvement of the water quality in our Fluval Spec V aquarium.

poly filter floss and 100 micron polishing pad for aquarium

The products are a pair of aquarium filtration media that work in tandem.  The first is Bonded Blue & White Poly Filter Floss Pad.  It works as a pre-filter to protect the second stage – a 100 Micron Polishing Filter Pad.  Let’s learn what each of these filter media do and how they work together to improve your aquarium’s water clarity.

Overview: Poly Pre-Filter and Polishing Pad Final Filter:

The star of my filtration system is this new media – the 100 Micron Polishing Filter Pad.  I was cruising around Amazon looking for new aquarium filter media to add to our tank.  This one came up over and over.  Reviewers described tank water so clear the ‘fish were floating on air’.  Seemed a bit too good to be true but it basically works that well!

The polishing pad filter media comes in a generous roll – 24″ x 36″ (61 cm x 91 cm).  It is very thin – less than 3mm (0.12″ ) thick.  One side is slightly rough – it is intended that this side be ‘downstream’ where the water exits through this surface.

100 micron aquarium polishing pad filter media

As the name implies, this polishing pad removes impurities larger than 100 microns.  The polishing pad is also available in a 50 micron variety if your system demands extremely fine filtration.

aquatic experts polishing pad instructions

The intent with a polishing pad filter media, as the name implies, is to give the water a final polish to remove the last of the fine impurities in your aquarium water column.  Prior to water entering the polishing pad, it’s beneficial to pre-filter the water to remove the larger detritus and impurities.  If you don’t provide a pre-filter ahead of the polishing pad, the polishing clog up quickly. I found a great complementary product in the Bonded Blue & White Poly Filter Floss Pad.  It comes in a three pack of 10″ x 20″ (25 cm  x 51 cm) roll and is around 45 mm (1.8″) thick (fully fluffed – it can be compressed down quite a bit).

Bonded Blue & White Poly Filter Floss Pad

This product is actually staged as well – the white floss layer at the top captures the big stuff.  The blue layer below holds the media together as a nice pad and is slightly more coarse to catch finer bits floating in your water.  Similar to the polishing pad, you need to pay attention to orientation – layer so that the water travels first through the white layer and then through the blue layer.

With the poly filter floss pad in place, it will make the polishing pad filter last longer and keeps it from getting clogged up (which could reduce flow in your filter system).

Adding Poly / Polishing Pad Filter Media to your Spec Aquarium:

Both the pre-filer and the polishing pad filer fit great in the space above the stock foam filter that comes with a Spec V aquarium.

I cut both to dimensions just slightly larger than the space of the filter section.  On the Spec V, the area of the filter section is 110 mm x 54 mm.  I cut with a little excess and settled on 113 mm x 57 mm.  I made the cuts using a good pair of kitchen shears.

Bonded Blue and White Poly Filter and polishing pads cut for Fluval Spec V Aquarium

Cutting the filter sections slightly larger than the space allotted ensures that the filter media extends all the way to the edge and does not leave a gap.  This is important. Water will take the path of least resistance, and if there is a gap (you cut the filter media too small) part of the water will bypass.  It will still work – just not great.

Since cutting these pieces is going to be a recurring task, I made a template to the proper size.  This way, I can easily repeat the cutting process.  I use the template and then transfer the outline onto the filter media using a marker.  Then I just cut along the mark.

cutting Bonded Blue and White Poly Filter pad for Fluval Spec V Aquarium

There are a few tricks to placing both the filters in the Spec Aquarium’s filter section. The first to be installed is the polishing pad. As I mentioned before, place the slightly grippy / rough side facing down.  I slip the polishing pad beneath the plastic filter handle that comes with the stock Spec foam filter.

Bonded Blue and White Poly Filter and polishing pads installed in Fluval Spec V Aquarium

Next, I press that plastic filter handle down.  Then, I place the poly pad on top.  (In the picture above, I hadn’t yet learned that I could put the poly pad above the plastic handle.  It works fine as pictured with both filter pads tucked below the handle.) Again, this pad is directional – place the blue side downwards. Sometimes the white part is fluffed up above the water line.  I just tamp it down a little.  It’s ok if this filter media stands up just a bit out of the water.

Performance of Poly / Polishing Pad Filter Media:

I will cut to it.  I’m very satisfied with the water quality in our Spec V tank since adding the combination poly and polishing filter pads.  Right away, I noticed a difference in water clarity.  It’s hard to tell when the CO2 system is on (lots of bubbles) but in the late evening when the CO2 solenoid shuts off for the day, the water goes crystal clear. It lives up to the hype.

crystal clear water in spec v planted aquarium

Both of these filters are washable.  When I perform my weekly water change, I rinse out all the filter media in the bucket of old tank water.  This includes: Stock Spec V foam filter, the (stock) biomax bag, 100ml purigen bag, and the new poly and polishing filters.  What I have noticed is that the other filter media are coming out much cleaner.  I’m used to seeing the stock foam filter give off a lot of detritus when squeezed to clean it out.  Now, it has almost nothing in it.  The new poly filter, however, is filled with gunk – absolutely disgusting, in a very satisfying way! I clean it out by swishing it around in the bucket of old tank water; I gently and repeatedly squish it between my two palms to get most of the dirt out of it.

The polishing pad is often darkened significantly, but I don’t notice it giving up much dirt when I try to clean it. I have settled on changing out both the poly and the polishing filter every 4th water change.  Some aquariums might require more frequent replacement depending on the bio-load, age of the substrate, etc.

One trick I have learned – don’t replace the filter media on the day that you perform a water change.  The weekly maintenance tends to stir up a lot of detritus and that will get removed overnight (and will thus load up inside the poly and polishing pads). Instead, swap them out the day after you perform your water change (and after the old media has full done it’s job – sparing the new media from the onslaught of stirred up dirt).

One thing you can observe that will help you know that the filter media is clogged:  Look at the difference in water level between the main (display) tank and the pump section.  As the filter media gets clogged (and the pressure drop across the filtration media increases) this difference will become greater.  With some observation, you will be able to tell the difference at a glance.  This can tip you off that it is time to either rinse out, or replace the filter media.

Here is what the pump water level looks like with a clean filter:

normal spec v pump section water level

Here is the pump section water level when the filters are dirty:

spec v aquarium pump section water level with clogged filter media

I get alot of comments from Spec Aquarium users that indicate they are frustrated with the performance of the filtration system.  For these people, and anyone who wants to take their tank to the next level of water clarity, I would highly suggest these two products.

Bonded Blue & White Poly Filter and polishing pads installed in Fluval Spec V Aquarium

On first glance, these filtration products seem costly, but it is not bad when you consider how long an order of both will last.  At the time of this writing, the poly pad cost $14 USD and has enough to make (approximately) 60 individual Spec V filter pads.  The 100 micron polishing pad cost $13 USD and has enough to make (approximately) 86 individual (Spec V) filter pads.  If you change the pads about every 4 weeks, this puts the annual cost for both filter media at $1.97 / year.  I think that is well worth it!

27 thoughts on “Poly / Polishing Pad Filter Media Mod for Spec Aquariums

  1. hi,
    I have (4) spec III.
    You mentioned the 50 vs 100 micron polishing pad but I don’t know which one will be best suited for the specs; each of the 4 have a single betta in them.

    I made the mistake of putting an almond leave in each for a natural type cover for them to relate to, only to have everything gunk up and months later still have minute residue that continues to dirty the tank. Im waiting for Fluval to get their water pumps back in stock, as the original are gunked up as well from that mistake. What a mess. Since doing that, I have yet to have clean, clear tanks of old.

    So the question, which one would be best suited for this situation, the 50 or 100?

    Great website, it has so much info that I really need. Thanks!

    1. I’m using 100 micron and that is what I would recommend. If your tank is having problems being dirty, the 50 micron will probably clog up too fast.

      1. I see, thank you. The tanks are not really dirty but not like before I used the almond leaves, Im very diligent to do the small water changes every week. The tanks have been crystal-clear over the past 3 years till then. ugh.

        Additionally, have you ever considered removing the center piece of the filter block and stacking the bio/charcoal/polishing pad just inside the perimeter of the block?

        By the way, not sure if you have seen this product, found it on Amazon, can replace the
        filter block on the Spec. Curious what you think or just overkill and try the polisher first?


        Glad to have found your site, very informative.

      2. I’ve seen that product. It’s way more cost and hassle than it is worth.

  2. I have two Fluval Spec V tanks. The first has the inTank media basket installed and I agree that it is a costly hassle. I found that whether it is the stock foam or other filter media, there is an issue with surface film build up around the weir intake. I purchased a small bubble bar and this portable air pump to break the surface tension around the weir:

    On my other Spec V, I removed the black plastic that made the filter area. I run a sponge filter with the another air pump from the link above.

    1. Thanks for the feedback on the InTank media basket. Interesting stuff.

  3. I’ve ran even my large 180 gallon tank with nothin but a pad of polishing media and bio balls (plastic media balls) for years. Everyone is amazed at how clean the tanks are with no charcoal or other adders.

    I found with my 12”x20” polishing pad I take it on the back porch and hit it with the garden hose I can blow all the gunk out and it’s like new. I’ve had the same pad for over 2 years now.

    1. Poly pad and polishing pad is the only way to go. But make sure you keep up on maintenance. Because like Nate said. These things are going to hold on to that gunk!

    2. Good feedback. Interesting about your practice of washing out the the polishing pad. I just chunk mine once a month, but it’s such a tiny piece in this tank that it’s no big deal.

  4. Hi Nate.
    Great job on the website.

    I just bought an In-Tank Media Basket for my Spec V and filled it with Eihem Substrat Pro.

    You should review the In-Tank Media Basket


    1. I’ve resisted the In-Tank media baskets just because I perceived them to be a poor value. Having said that, It might be worth writing review. The product’s real value comes with the saltwater tanks as I understand almost everyone running a marine EVO 13.5 opts to get rid of the stock filter sponge media – the In-Tank media basket has more value in that application.

    1. Paul, Thanks so much for bring these to my attention. I’ve got some initial opinions on those products and will hopefully write about them soon.

  5. Hi! I am going to be setting up a Spec III….. would you recommend using these filter floss/polishing pad modifications for the Spec III as well? Do you have any examples?


    1. Yes, I’d recommend this mod for the Spec III as well. Same filtration system – same advantages.

  6. Hi Nate. Thank you for sharing this tip and I couldn’t be happier with the water quality. I do have a question however.

    I will have my first water change coming up since adding these two filter options. Once the water change is complete can I put them back right-away as they were after rinsing them out or should I wait a day for the standard filter to do it’s job cleaning up the larger bits and then put these two back in.

    Thank you for your help.

    1. After you have squeezed/swished them around a bit (in your old tank water, during the water change) to clean them out, I’d put them back in right away. If you are going to replace the Poly and/or polishing pad, do that the next day.

  7. Hey Nate. Does this mod reduce the filter outlet flow?

    Thank you.

  8. I just tried these filters in my Spec V and wow! made a world of difference. Thank you!

    1. Glad it worked well for you – one of the best mod’s I’ve made to our Spec V!

  9. I’m so glad to have found your website! My husband and I just got our first Spec 2.6 gallon. We’re in the process of cycling the tank after scaping. Do you recommend for us to wait until there’s enough bacteria built up in the biomax filter before adding this mod? I wasn’t sure how/if these fine particle filters affect the nitrifying bacteria and nitrogen cycle. Thanks in advance!

    1. Adding these filter media to your tank will not affect the cycling process in any way. However, you might wait as there is little need for additional filtration for such a young tank (probably fairly clean).

  10. I had my poor little betta swimming in pea soup then I read this article. Here is how I converted pea soup to crystal clear water….

    Now about 20 days ago I started getting an algae bloom. Soon my poor Kiro was swimming in pea soup. I made a quick consultation with Dr. Google and came up with the following plan. All the products are available on Amazon and all of them are inexpensive. And understand, 3 days after installing this system, I have crystal clear water.

    Here is what I ordered:
    1. 5W UV-C Algae Bloom Clean Light for Aquarium Water Clean Green Clear Waterproof Clean Lamp ,
    2. Polishing Filter Pad – Superior Polishing Pad for Aquarium
    3. inTank PREMIUM THICKNESS Aquarium and Pond Filter Floss
    4. Ultralife Blue Green Slime Stain Remover
    5. Blue Ribbon Pet Products ABLPLY7 Polyester Floss Bag Filter Media for Aquarium
    6. Fluval SPEC Biomax
    7. UP Aqua Rain Bar Unit Fish Tank Outflow Pipe

    Ok maybe it is overkill….but my little buddy deserves the best…..and now is buzzing around our Fluval Spec V where before he lazed in front of the filter……let’s see what else I can order for her!

  11. btw….I forgot to mention, your website is my “go to” for my Fluval Spec V issues……your advice was essential to clearing up my “pea soup” aquarium.

    1. Awesome. You went all out. UP Aqua Rainbar looks like an interesting product.

  12. Hello! This article was very informative! I bought pre-filter sponge and polishing pad you suggested. My question is what order do I put it in my hob? My tank has a lot of brown diatom algea which has gotten better after upgrading filtration. I have filter sponges, bio balls, , , and pre-filter sponge ad polishing pad you suggested.

Leave a Reply

Your email address will not be published. Required fields are marked *