Sponge filter need replaced?

[chemgrl08]

Hi all! Perhaps this is a simple question, but can I get some feedback on this?
I have a 30 gal tank and everything has been fine for the past year or so. I've been cleaning/squeezing out the sponge in the removed tank water when I clean and haven't had any problems with dirt or chemical levels. After one of my females laid eggs, the tank suddenly got very dirty/misty overnight. I changed the water and cleaned the sponge again but it didn't seem to help. I had an extra waterfall style filter laying around and put that on, which seems to have cleaned everything up substantially.
My question is: Do the sponges on sponge filters eventually need to be replaced? It doesn't seem to be damaged, but clearly it's not doing the job. (I think I can just put together a DIY sponge instead of buying an "official" one, right? Then again, it's really not expensive.)
Thanks for your insight!

 

[michael]

Sponge filters need replaced when they start to fall apart or can no longer be wrung out. When an axolotl lays eggs their is lots of biomass added to the tank. Some of the extra load is still there when the eggs are removed. It is best to do a huge water change after egg laying and make sure your filter system is working at peak performance. Your filter was probably just overloaded.