CerMedia MarinePure 1.5-Inch Sphere Bio-Filter Media for Marine and Freshwater Aquariums, 2-Quart

water cleared up in a matter of hours. Magic

These are great! I have seen some people say that they COMPLETELY break down into small particles or are a threat to ruin aquarium equipment, this has not been the case for me. Of course overtime there will be pieces that break off (as it is ceramic) but they fall right to the bottom and can be siphoned out easily. I have had 2 "gallons" worth in the "chaeto" section of my sump of my 140 gallon reef tank for over 2 years. My ammonia, nitrate and nitrite is 0 and has never raised above 0 on any tests. I do perform weekly 10% water changes religiously and do only have 9 medium-large size fish in my system but I feed like crazy both the corals and my fish. Obviously they work in conversion of Ammonia. I can't sit here and say I'm a marine biologist and blast the product but from a long time reefer with long time perfect parameters I can tell you these work well. Add these while taking the time to maintain your tank with filter pad/water changes and you can run a successful aquarium.

Item arrive and box has so many power and packet inside was already opened. Ain’t sure if it’s contaminated

I found that it does take a while for bio life to take to these spheres unlike other bio media but does the trick given time

These are one of the best materials around, but the size is rly rly big, I split some into halves to try and get a few more into my canister filter, its a bit hit and miss fitting even 1 row in due to the size (although I deliberately didn't want too small a media to restrict waterflow). Also be aware they are super sharp.. even handling them to wash.