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Home » Aquarium Supplies  » Filter Media  » Mechanical  »  Poly Filter 4 x 8
Poly Filter 4 x 8
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Poly Filter 4 x 8

Average Rating 4.5 42
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Poly Filter 4 x 8 Information

The POLY-FILTER is for filtering and purifying both fresh and salt water aquariums. It is a formulation of a special patented material bonded to a synthetic matrix. By means of a unique proprietary process, the POLY-FILTER is made impervious to salt and is also organic loving to certain materials. It can absorb and adsorb contaminants and other toxic materials found in nature or added to fresh and salt water with or without fish and invertebrates. Medication added to fresh and salt water aquariums for treatment of diseased fish will automatically be removed by the POLY-FILTER after serving their intended purpose before the medication can produce a toxic effect on the fish.

The POLY-FILTER is non-toxic and harmless to biological filtration because it allows a sufficient amount of ammonia to reach the biological filter in order to sustain the bacteria culture. The POLY-FILTER provides a supplemental means for removal of ammonia when the biological filter is unable to break down the excess ammonia and its concentration increases rapidly. Then the POLY-FILTER adsorbs the excess ammonia while the biological filter readjusts to higher ammonia input levels. Changes color when exhausted. 4" x 8".

Operating Instructions

Freshwater Application:
Add Poly-Filter to any holder or apparatus at any time.

Establishing Marine/Reef system:
Add Poly-Filter so water can pass through it.
For Maximum Filtration: Eliminate all water bypass.

Poly-Filter in established marine & freshwater systems:
  • Conventional power filter: Place Poly-Filter on bottom plate. Cover with gravel or floss. Do not restrict flow.
  • Plastic undergravel filters: Place Poly-Filter on top of the undergravel plate. Cover filter and plate with gravel.
  • Canister-type power filters: Place Poly-Filter in the chemical filter compartment. Add floss according to manufacturer’s instructions.
Medication removal (parasite and antibiotic treatments):
Remove Poly-Filter from water before any type of medication is added. Follow medication instructions issued by the manufacturer. After treatment is complete, place Poly-Filter back in the water to remove traces of medication. Test water for safe levels. When safe, remove discolored Poly-Filter, dry and save for next medication. Place new Poly-Filter in the water for removal of conventional organics and water purification.

Adding vitamins and trace elements:
Remove Poly-Filter from water before adding vitamins or trace elements. After 12 hours place Poly-Filter back into water. Poly-Filter will not remove calcium, magnesium, strontium, barium or alkalinity supplements. Poly-Filter will not remove trace elements included in marine salt mixtures.

General maintenance comments:
Poly-Filter turns color when removing medications. Aqua to Dark Blue: Copper or Copper salts. Orange: Iron. Bright Red: Aluminum. Bright Yellow: Ammonia, Amines or Solvents. Dyes: Color of the solution when added i.e. Methylene Blue: Pale Blue. Malachite Green: Light Green, Tannins/Humic acid: Dark Brown, Organic Wastes: Light Tan progressing to Dark Brown. Poly-Filter extends time between water changes. Add de-chlorinated water to make up for evaporation loss. If pH shifts below acceptable level change water and add a new Poly-Filter. Heavy slime producing water conditioners can surface coat Poly-Filter and interfere with absorption performance. In marine water, soak in 3% hydrogen peroxide then rinse (in freshwater) well. In freshwater soak in 10% marine salt water solution then rinse (in freshwater) well.


4 x 8 filter pad

Manufacturer Info

In 1976, Poly-Bio-Marine, Inc. developed, patented and commercialized a truly unique product, the "Poly Filter". It was specifically designed for chemical filtration in the aquarium.


No Warranty

Poly Filter 4 x 8 Reviews

Average Rating
(42 reviews)
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of 5

Poly Filter

Reviewers Rating Great

Posted: 12/24/2014 from BOYNTON BEACH, FL UNITED STATE
4.0 5
Experience Level: Intermediate

Comments: Great stuff it takes a day or two to see change at least for me it does.

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Does it's job

Reviewers Rating Great

Posted: 11/7/2014 from MESQUITE, TX UNITED STATES
4.0 5
Experience Level: Intermediate

Comments: I've been using this product for 5 months now. I started using it to battle a small algae problem in my tank. So far, it seems to be doing it's job. It lasts for a few weeks and turns a nasty color, then just take it out and swap out a new one. It would probably work better if I changed it out more often, but I'm too cheap to do that. I would recommend to anybody with an algae problem or in need of a good filter.

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feed back

Reviewers Rating Excellent!

Posted: 9/10/2014 from CENTERPORT, NY UNITED STATES
4.5 5
Experience Level: Beginner

Comments: Works very well.

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All time classic

Reviewers Rating Excellent!

Posted: 3/27/2014 from Mexico, City
5.0 5
Experience Level: Intermediate

Comments: I´ve been using this product since long time ago, and always I receive the same results, great product for any kind of aquarium.

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Poly filter

Reviewers Rating Excellent!

Posted: 3/18/2014 from WEST SACRAMENTO, CA UNITED STA
5.0 5
Experience Level: Intermediate

Comments: This stuff is great! Have a small fresh water tank and 90g salt water. Had some minor algae issues in both, but no more! Both tanks showing decrease in less than a week! Definitely will continue to use. Had slight fluctuation of pH in my saltwater tank but now reading better than before! Great produce and easy to use.

2 of 2 People found this review helpful, did you? Yes No

Happy Water

Reviewers Rating Excellent!

Posted: 3/8/2014 from OCALA, FL UNITED STATES
5.0 5
Experience Level: Intermediate

Comments: I have used Poly Filter for years. The poly filter keeps my freshwater tanks in check. Filters out all the bad and leaves the good. Just read the back and know the color changes.........I change mine once a month. Very happy with this product. MarineDepot web was so easy and great service.

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Poly Filter

Reviewers Rating Excellent!

Posted: 9/9/2013 from FALLBROOK, CA UNITED STATES
5.0 5
Experience Level: Intermediate

Comments: Good filter, it can be cut to fit almost any tank system, I would recommend that at least try it for a month. It can be cleaned then flipped over and used again. That's what I do.

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Excellent Product!

Reviewers Rating Excellent!

Posted: 7/30/2013 from CEDAR PARK, TX UNITED STATES
5.0 5
Experience Level: Intermediate

Comments: This product is a must have - especially for smaller tanks!

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poly filter 4+8

Reviewers Rating Great

Posted: 7/27/2013 from MONTE RIO, CA UNITED STATES
4.0 5
Experience Level: Intermediate

Comments: The poly filter works great, the water seems to pop with vibrancy and clarity. It works buttersmooth with my other filters, the only thing wrong about it is that it clears water so well that you have to clean it or replace it every 2 weeks. Would highly recommend this product if you want high quality water and willing to clean or replace the filter on a bi-weekly basis. Thank you Marine Depot for another excellent product!

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Don't Use Unless You Have To

Reviewers Rating Unsatisfactory

Posted: 4/26/2013 from GLENVIEW, IL UNITED STATES
0.5 5
Experience Level: Expert

Comments: I have heard nothing but great things about this product, however after using this product I would never use it again unless I tried every else first. My water parameters have always been perfect and after using this as an alternative to carbon I found that within days my sps had a negative reaction to something the poly filter was pulling out and began lightly bleaching. My conclusions for this product are that you shouldn't use this as a preemptive product but reserve it for emergency use. If everything is good with your tank don't take the risk of sending something out of whack and then spend the next month figuring out what went wrong. This product adsorbs just about everything so I don't buy that trace elements do not get pulled out of the water as well beneficial nutrients the system needs. Stick with Carbon or your usual media and you'll be better off.

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