New to the site and forums. Have been an avid fish hobbyist since 1995. I've had everything from Oscars to Pirahnas to Jack Dempseys. My 55 gallon tank I have had since the beginning and currently has 2 small, 2-3 inch, oscars. I have a 37 gallon aquarium that my girlfriend has populated with "pretty" fish (guppies, platys and a couple frogs). I just purchased a 90 gallon aquarium that I am planning on moving the Oscars into. I have been on here doing research trying to find the optimum setup for my Oscars. I have decided against the canister filter for the simple reason that I can get the HOB Filters and put the heaters right inside of them without putting them in the tank for the Oscars to knock off the walls later. Here inlies my question. While comparing Canister and HOB Filters, I read that bacteria lives in the media and helps to take care of any ammonia that is in the tank. I have always changed both filter cartridges at the same time basicly getting rid of all bacteria in the filter. Would it make more sense to change one at a time and alternate changing filter cartridges? I currently use the Aqua-Tech 30-60 Filter in my 55 and an Aqua-Tech 20-40 in my 37. I like them because they take the same cartridges. I am planning on running dual 30-60's in the 90 gallon with heaters in each one. How often should cartridges be changed and does it make more sense to alternate them to eliminate complete bacteria loss? Any info would be greatly appreciated. Thanks.

yes, i have the same filters on my 55's, alternating is the way to go. but be warned. those 2 30-60's will NOT cope with the bioload 2 grown oscars will put out. you will be changing your tank water 2-3 times a week when they get big. you need a canister.

i can say that with certainty, because i had an oscar in a 55 by itself with one of those 30-60's and it was not enough filtration for the tank, i had to upgrade. so even tho you have two, you have less than twice the water there, and twice the fish. so do the math, it doesnt add up lol.

I have a 120 gal tank and used 2 emperor 4oo HOBs; they were never enough. They were rated at 400gph each but I think(after losing several fish and having constant water issues)that they cannot hold enough bio material.With Oscars you need a ton of bio to cope with all the waste they produce.

Makes sense. I like the canister filters. My issues with them were the heaters and how to aerate the tank. I'm too cheap to get the Eheim Pro II right now. Don't know much about the inline heaters. I'm using 2 powerheads in my 55 and planned on doing the same in the 90. Is there any other way around this with the canister filter?

hey welcome to the forum!

I have had internal heater in my tank for many yrs without any problems. place them in protective plastic case and no oscar will break them. got to admit though the tank looks better if you don't see the heater. i wouldn't buy a filter with a built in heater. cost is far more than its worth.

i hid my heater in an overflow that stays full of water. cant even tell its there.

I broke down and bid on a Jebo 835 Canister Filter on Ebay. I'm checking into Inline Heaters that I can hook up to the return hose on the Filter. I guess my next question is, how do I aerate the tank without the use of an undergravel filter and powerheads? I'm anxious to get the tank set up but want to do it right the first time. Thanks for all the advice.

brichter04 wrote:

just position the discharge pipe above the water high enough to create rippling
movement. that will aerate your tank without powerhead.