Changing filter sponges

I have 1 axolotl in a 70l tank, with a Juwel Bioflow 1 internal filter. The tank has been running for 7 weeks, with Bobothy the axolotl in residence for 5. He seems relaxed and well.

I change 20% of the water every week. My non-urgent questions are: am I doing right by only removing anything obvious, like plant matter, from the filter when I do the water change and leaving it 'slimy', and squeezing out the 2 sponges from the filter in siphoned off tank water until they are blue again, rather than brown ? Also, the sponges do not seem to be deteriorating, do I need to replace them at any point ? I have also seem just a few very small (about 2mm) white worm-like creatures in the tank, are these normal ? Thank you for any advice. :happy:

It sounds like you're doing things right. You only need to replace the sponges if they start to deteriorate.

Thank you very much, Otterwoman. Great to hear from the US.

It sounds perfectly fine to me! I find that if I just squeeze out my sponge filters once a month or so, it gets them unclogged if they aren't already, and of course leaves the good bacteria in place.

I'd have to see a picture, but the little worms are likely totally normal, possibly detritus worms. Although if you see some, you probably have a bigger population than you think! (you can check at night by shining a light in and seeing them congregate on the glass, etc). They aren't harmful to your axie, just a nuisance if you find them so (or if you notice them actually clogging your filter parts). If you want to cut down their population, you can do extra water changes and be extra mindful of cleaning waste and excess food.

If they look sort of flat instead, they might be planaria but I believe those are handled the same way.