K1 Filter Media PREMIUM GRADE Moving Bed Biofilm Reactor (MBBR) for Aquaponics • Aquaculture • Hydroponics • Ponds • Aquariums by Cz Garden Supply (1 Gallon)

I have these in my home made moving bed filter for my koi pond. They take a few days fully colonize and to lose some of their buoyancy, (be patient, they will start to move around once the bacteria make a home of them) but when they do boy do these things move! In only a few weeks they have changed from a translucent white to a slight tint of yellow/tan, which means they are fully colonized with nitrifying bacteria (the good stuff) and they are working to remove harmful nutrients from your pond or aquarium. I highly recommend.

This stuff is awesome. I was a little concerned at first because it was kinda buoyant, as you can see in the picture, but now that it has been circulating for a few days the bacteria has started to weight it down slightly and everything is moving in the fluid now with minimal air movement. And some spilled over into my pump output of my sump and that is fluidized very well!. Very happy with the product. I am only using 1L in about 2gal of water volume in my sump. Might ad .5L later on.

The first day I put these in and tried to start up my fluidized bed section of my sump they all floated.. so much they they would push up and over the wall of the tank and spill into the other sections of the sump and in some case over the even high tank wall and out onto the floor. At first I thought that maybe this wasn't real K1 Kaldnes. By 48 hours I noticed they weren't floating as much and by the next day it was fully fluidizing. Good product, great price.

I owe CZ Garden Supply an apology. I returned them since they all floated and would not (initially) circulate in my home made air stone driven fluidized bed bio filter (formerly known as the 59 oz. Tropicana juice container with 1/8" holes drilled in the top, foam over the mouth, a hole to snap in a suction cup and an air line, and an airstone). I had purchased some K2 media before this, and the first K2 I bought circulated well right off the bat. This earlier experience made me think these media were defective. CZ refunded me right away and without question after I returned the product.After buying more K2, the second batch floated just like these ones had. I decided to let the media age in the running bio filter. After making 3 or 4 of the same filters (some with McCormicks 4.4 oz bac'n pieces containers), experience has shown that the media which floats very aggressively at first all begins to circulate within 7 days (most within 3 days) of filling the container and running the air stone. I figure the bacteria is starting to grow during these 7 days, and the circulation of the media only helps the filter once there is a reasonable amount of growth on the media anyway.These bio filters are very easy to make (check YouTube) and they look very cool circulating in the tank and making me hope they are helping the fish.Now that I see my mistake in returning this product once, I will give it another try. Sorry CZ and thanks for being cool about the first return.

I am using this in canister filters for a couple of my aquariums (22 & 50 gallon size). This was a big bag - I will never run out! Nice big bag of quality K1 media. I may decide to do something with my pond area next summer and if so, I will definitely use this.

This product is cheap and works great for filter media for the aquarium!!

I feel like the K1 Filter media has really improved the water quality in my pond. It is low maintenance and cheap to buy. I am slowly replacing my bio filter pads that I have to clean non stop for this. I don't feel like my bio filter pads are working as good as this because of the lack of oxygen my pads are getting. With these, you just add an air-stone to the bottom of the container you have them in. I use a five gallon bucket and drilled holes in the top and in the bottom to allow enough water/air flow for the media to be consistently moving around.

Happy :)