choochiegirl

i have a Tetra Whisper Advanced PF 30-60 for my 30 gallon tank. It is currently cycling with no fish. There are 2 charcoal filters & 2 filter cartridges. I'm pretty sure that i should only change one side at a time to keep the good bacteria in one side while the new one acclimatizes. But how often should I change them, when I do need to change them? My hubby opened the box and of course tossed the instructions I know i don't need to change it now, but i would like to buy a spare set to keep on hand just in case.

sgould

I have Whisper filters that recommend changing the cartridges every month. Many fishkeepers, however, will tell you not to change that often as you are disposing of a portion of your good bacteria every time you do. Instead, they suggest only changing the "floss" portion of the filter once it starts to fall apart. I do tend to change mine more often...every month to month and a half and have not yet had any problems. Mine also have 2 cartridges and I only change 1 at a time as you mentioned. Carbon (charcoal) filters, however, are another matter. They can only absorb so much, and then they start to leak pollutants back into the tank. Those you should definately change regularly.

Luniyn

I use these cartridges in my whisper filter. The 2nd sponge provides enough bio-filtration along with the black sponge the filter comes with, to not have to worry about changing the mechanical part with the carbon in it every 3-4 weeks. I haven't had any problems with losing too much of the good bacteria by doing this because I haven't seen any ammonia in my tank after a filter change. Also if you don't want to use the carbon filled filters, just get the clamshell of that filter with the extra sponge, and then cut to fit some of these mechanical filters to use regularly. Then you only have to rinse those out every few weeks when you do a water change (rinse them in the old water that you are removing from the tank).

griffin

another method is to get some plain filter floss (or quilt batting) from walmart or a fabric store. just make sure it doesn't have any flame retardants or other stuff on it. just cut to size and use those as replacements. much cheaper than getting the premade filters.

i tend to only rinse/replace when the flow gets to be too low.