hi all ive just finished a fish cycle using a u4 fluval filter so how do i go about changing filter can i take one out and wash and squeeze it in tank water or do i replace one new one for one used one or wat you see there about 5 weeks old but i dont want to loose the good bacteria in them so if you have the answers i would love to hear your comments thxs or just leave them a bit longer as 5 weeks is not that long

There's no need to change the filter media. The sponges should just be rinsed in old tank water to get the worst of the muck off and then put back in. They should last years before they need replacing. If the filter has more than one sponge, wash one one time and another the next. If it includes fine white filter wool pads, those do need replacing, but carry very little bacteria so it's not a risky thing to do. Any carbon pads should be replaced with extra sponge to provide more room for bacteria to live in, as it isn't necessary to run carbon except when removing meds or similar.

thanks fish