I would prefer the Sponge filter because it has many benefits
. Their affordable price tag and shrimp safe form make it an easy filter to get started with. Mechanical filtration in a Sponge filter works by drawing water through the sponges. Over time, a biological colony of bacteria grows on the sponge offering Biological filtration that break down harmful aquarium waste.

Maintenance on a Sponge filter is very easy as well. All you need to do is remove one sponge during your water maintenance, rinse and squeeze it in aquarium water, and then put it back on the filter inlet. Overall the Sponge filter is an excellent choice in any shrimp tank.

I totally agree with what he says cheelito, since the foam filter is much better for the reasons that he says, sponge filter produces aeration and filtration for shrimp is produces a bacterial substance that protects much better to the shrimp, that dirty waste, whether in the fish tank sponge attracts it and helps to maintain cleanliness, as it said cheelito, really it is very economical compared with other types of filters, for this reason, it is very convenient, I can tell you from my own experience that it is easy to clean, not lost so much time, in my case sometimes by how quickly I have to do my activities It's very convenient to have this type of filter, since if it needs to be cleaned in less than 10 minutes I managed to do without having to wait a long time to make sure it is completely clean.