CerMedia MarinePure1.5-Inch Sphere Bio-Filter Media for Marine and Freshwater Aquariums, 2-Quart

Good media

Our little 10 gallon tank was struggling to keep up with the shubunkin goldfish we got as babies. (They can breed with koi, that should have been a glue to me that they are HUGE fish.) I read about these and bought a box. I literally just tossed them in the tank, there’s nothing hard about it. But it made the an immediate difference in water quality. The water cleared, the nitrifying bacteria had a place to live, and it cut water changes by half. Living in a crowded tank is not ideal, but if you ever need to do it, this will buy you time to set up a better situation for your fish. I will never set up a tank without it!PS- transfer some balls from old tank to new tank to speed up cycling!

This is a fantastic product. I put these in one of my sump baffles and let the tank cycle for about 6 weeks. Then I tried to spike the ammonia in the tank with flakes, mysis shrimp, uncooked jumbo shrimp, a chunk of walleye and even a shot glass full of clear ammonia and I haven't been able to get a positive ammonia test result. I thought I was doing the testing incorrectly but two LFSs confirmed that there was ZERO ammon-sies in the water.The picture is kinda crumby with the red plant light in the fuge, but you can see the placement of these orbs. It works like a charm.This is the fuge light, btw. This thing performs way better than I'd expected. My fuge grows so much chaeto that it's almost annoying.https://www.amazon.com/gp/product/B00GNWK2XO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Very porous. Seems to do well and the sphere shape does not hold a bunch of detritus. I have minimal rock in my tank so these are doing a good job allowing bacteria to propagate and a nice home for various small critters.

There are many levels of active bio media. Just like socks they come in all sizes, materials, thread count, thickness and etc. What I mean is some aquariums can do just fine with average performance bio media while others need above average performance for their sensitive fish and heavy stock tank. I fit in the later. I wish to avoid all the "my stuff works better than your stuff" and just state a couple of facts. 1. MarinePure is the only manufacturer that provided scientific proof of their claims when I did research on 5 major brand name products which I choose to accept as valid. 2. MarinePure is one of few products that offer rock shape items and undergravel 1 inch block. Why because this product can replace "live rock" IMO if you seed the bacteria properly for salt water. I have used this product in salt water and in fresh water and it is nothing short of amazing, reliable and predictable IMO. I have used it with Seachem Stability and could not ask for better results. In salt water I just laid them in the sump and in fresh water I placed them in the trays of canister external filter but being somewhat large I filled in small spaces with EHEIM Substrat Pro for maximum volume in the canister. I have used Seachem Matrix, Fluval Biomax, live rock and etc. This is my "go to" first choice now every time, It's performance has proven it's value to me.

Replaced the bioballs that came with my SeaClear system 2 tank with these. Fantastic product with much better bacteria growing capacity. Help keeps water parameters extremely stable. Have a reef tank and have been able to push water changes back to every three instead of every two weeks with no degradation in water quality.

I can't even tell you how many different brands/types of bio biomedia products I have used over the years. I bought a box of these and actually fitted them in one of my HOBs, they are working amazingly well so far.

These filter media balls are designed to have maximum surface area. I threw them into the return pump area of my sump on my reef tank.Within 24 hours, pods were crawling all over the balls. A week later, my water is looking extra polished and my nightly pod swarms have gotten thicker.Macro algae and corraline algae have taken up residence quickly on these media balls. I used to only have live rock chunks around my returns but after putting these on top of the live rock in my return area, I have increased the filtration provided by that section many times over.I highly recommend these!I received this product at a discount in exchange for an honest and unbiased review.