Foam in the laminar jet?

Hi.

How many of you are using some kind of foam in the laminar jet?
I have built some small jets and i am just using foam in them.
but my foam falls apart after some time. Whats the best material to use in the foam?
Polyehter or polyester, or is there some other material?

In what kind of water are everyone's jets running in? Chlorinated or just tapwater?

i use aquarium filter sponge.
and use normal tapwater with some additives so you can see the colors beter