I have found the replacement catridges for the 400's cheap on Dr Foster and Smith. About 2.00 each when you order in bulk 12 or 24 backs. My brother and I keep saying we will split the cost on a bulk pack, just haven't each had the money at the same time yet. He runs a Emp. 400 on a 75 salt setup. I like the idea of transferring a filter from an established tank, should have thought of that before instead of going with all new ones. I still like the idea of getting a ac 110 to go with it. One 400 left on my 75 leaves it set up for whatever I put in it next.
On my 400's I don't use the cartridges instead I cut blue filter pad and place it in the gray carbon cartridges. Much cheaper and I hate carbon so it's a win win.
Sent from my iPhone using MonsterAquariaNetwork app