DIY Nano Sponge Filter Question

[Bradley1]

Hi, so I've been looking around to find ideas for a DIY sponge filter for my shrimp tank seeing as the filter I got with the tank is too strong. I came across this one on youtube:

Does this seem like a filter that would work for a 4gal planted tank with Red Cherry Shrimp? Also, I'm not sure I fully understand where the airstone is meant to be placed... in the sponge or resting on top of it? -Thanks

 

[Fishey bricks]

I think that would work, the only point I have to add is these filters work by surface area so the more surface area on the sponge you have the better.