The canister's lid is 8.25"x9.5", the canister's bottom is 8"x7.75"
The height of the container is 12", but with the lid on the total height of the canister is 16".
There are 3 baskets inside that are 6"x6"x3" for filtration media. There is one removable divider in each basket, which gives the basket 2 levels of space.
Thanks a lot ck. I was asking because I have had a box of 1 1/2" bio balls for a long time and I want to use them. I needed them when I was making my CO2 diffuser. I only needed like 5, but I had to get a box of like 80 or something, so I want to use them. I just wasn't sure if they were too big. I will take the ones that are in the CO2 diffuser and put them in the filter sinse they have been in there for months. They will have bacteria on them and can help seed the filter quicker.
Looks like chefkeith answered you before I could get back to you.
Them balls should fit with no problems. I stole some of my kids army men. I boiled them for just in case. I have been using them for about a year now without a problem.