I have never has a problem with nitrates so didn't buy it for that I bought it because it looked nice online but when put in the tank it looks very fake and almost like a silky rug like ball cant comment on if it actually works but I does not look nice in tank. at least to me it does not

I bought one of these to try.....I couldn't find anywhere online (or on the package) where it stated what the resin is. I used it in my 10 gallon freshwater aquarium for a short time. It did lower phosphates from 1 ppm to near 0 ppm - however, my GH raised to more than 8 degrees (General Hardness). I took it out, and put it in my 20 gallon. It lowered the phosphates from around 2 ppm down to less than 1 ppm - BUT raised my GH to more than 10 degrees! (I did leave it in the 20 gallon longer). I have many tetras which would get stressed with hardness levels that high. I took it out and did water changes in both aquariums (both now have GH readings where they should be. I also added more conditioner to detox the added metals). Other than a mild case of Ich with three new tetras - no real harm done (the three black neon tetras are already spot free - thanks to a long trusted product that is safe for all fish - and is available here at Drs. Foster and Smith). I use Reverse Osmosis water - and set the hardness to suit my fish. The only explanation was that the Fluval released Iron oxide into the water (I already confirmed that can happen with another Fluval product - company confirmed it). This is the confirmation I got from Fluval about the Moss Ball: >> "The resin in the Moss Ball is likely to be the same resin that is used in [the name of the other product]." If your fish are not sensitive to ferrous/iron oxide, then you will be fine using this. I just know that it isn't good for tetras. Now that I use Reverse Osmosis water and can set the hardness (and pH), all of my fish are happy and healthy - and I am able to keep tetras.

I ordered four of these for my 55gallon tank. They are pretty cool, i really didn't know if they were real of not when i bought them but they are fake. Its a great thing for me since i hate the real ones. They always broke up and got into my filter. These ones have i think carbon inside them and the green stuff feels like hair into you get them wet. They look real after your rinse them down. You got to put them in water and squeeze the ball to get all the air out so it doesn't float. Overall i am happy, and will by 4-5 more in the next few weeks.