I hate AC filters! Some of you have heard my opinions on them before, usually bad reviews. Anyway I think I have proved to myself that two Penguin 350s will out perform and harbor more bacteria hands down to two AC 110's. When I moved the two tanks to my moms the 120 had two Penguin 350's, the tank has an oscar, Red Devil, 4x Silver Dollars, 3x Synodontis cats, A sailfin Pleco and two JD's. Believe it or not that was adequate filtration with weekly 50 % water changes. The 125g had 2 AC 110 filters and a Rena xp3 the tank was stocked with two Jags with the same water change interval.

When I moved I moved the AC 110's to the 120 and the Penguins to the 125. Making the 120 have only two AC filters. I was thinking that would actually be more filtration. Well I was wrong with similar feedings as before and no other changes and water testing I have proved to myself that the Penguins perform much better and must have a much larger area for beneficial bacteria. I will never buy one of those junk boxes again. I have always used bio wheel filters and dont mind they are a little more noisy, the biowheels win hands down im my book.

You can get even more go out of the penguins, modding the grey holder carts that come with them and using an air pump through 'em.

Anyone else have any input on the two or other filters?

I've never used the AC's because I've always had good luck with the Penguins and Emperor filters.

Anyone else have experiences good or bad with AC filters?

I used an AC on my tank, but I also had a Penguin on it. The Pengiun ran great and was way easier to take care of. The AC I found hard to get it primed and clean.

Well with more benefical bacteria, who needs more power. Good discussion if yr lookin for other options as far as media I agree the ac filters definately have more accomidation.

I use to use a filter sponge and bio balls in my penguin when I had it, and it ran great. The filter cartridges where expensive for it, but Wal-mart carries a cheaper filter made by Marineland that uses the same cartridges as the the Penguin's and Emperor filters at half the cost. I stop using the cartridges after trying other media and finding that it work and lasted longer, saving me money.

Ive been told the ac is indestructible, then why do both my ac 30's run like shit? Weekly cleaning and still no better, the power isnt that great and they are noisy as hell. Ive had to replace the magnet in my ac 4 times since Ive had it, which has only been about 3 months. Fluvals all the way for me

I like canisters too but I am a sucker for HOB's and Emperors are the best IMO for my needs and celticwraith is right you can stuff more than just the filter carts in those things.

There's no need to buy new cartridges for the emps or any filter that uses cartridges for that matter. When I get mine I slit the bottom of the cartridge and take the carbon out then I just rinse out the cartridges at every water change. They will last a long, long time. The emps do have a basket which can hold sponges and other media but l can't really speak for the AC's capability for media because I've never owned one.