Filter cartridge and the biological filter

what you should do is put a rinsed new filter in the pump or in the tank for atleast a day before you remove the other one.

if you just remove and clean you old filter in old tank water then it will not remove any bacteria, and you can use it for another 4 weeeks

Really, the easiest way to solve this is to buy an AquaClear 20. These filters are quiet and have a foam block that never needs changing to act as your biofilter. Just run both filters for a while to get the new filter cycled, and then you can junk the TopFin when you run out of cartridges.

Why is all this a good idea? Well you don't need to run expensive Activated Carbon in ANY filter all the time. With the AquaClear, you can put whatever media you want in, which means you can leave out the Carbon you don't need. Leave the foam sponge in, and then fill up the rest of the basket with "filter floss", also known as NON flame-retardant quilt batting.

Since you aren't buying new cartridges, and a years supply of quilt batting shouldn't run you more than $5, the new filter will quickly pay for itself.

SirWired

I agree...get an AquaClear 20.

Unless the filter media is seriously falling apart there is no need to replace it. Instead every couple of weeks rinse it out in old tank water from a water change. When it is time to buy a new filter media you should leave in the tank for about 1-2 weeks before completely removing the old filter. When you replace the old filter media you can also leave cut out parts of the old filter to lodge in with the new filter to help jump start the cycle on the new media.

IMO you don't need carbon at all unless you are trying to remove medicine or tannins from the water.

In a non planted aquarium you should use carbon.

H3D said:

In a non planted aquarium you should use carbon.

Click to expand...

No, it is not necessary. It deactivates itself after a week or two anyway and is simply a waste of money unless you are removing meds, toxins, or tannins. I have never run carbon in my tanks (except for specific reasons and temporarily), planted or not, and I have never had a problem. Running it all the time will not harm the tank but it doesn’t make a difference. If you need to use it all the time you most likely have a bigger underlying problem that needs to be dealt with. So, with proper tank maintenance it is not needed. Plus water changes and maintaining proper stocking limits on the tank is cheaper then buying carbon.