I am only running the sponge filter and was thinking about using two of them but setteld for one dual sponge, this is supose to be a "cheap" tank. i think i have like $15 into it right now and that is because i had to buy the sponge filter and air pump.
Also, i do not have a testing kit so idn what my water is sitting at... mayb ill go buy a few ghost shrimp to start with.
I would avoid adding those if you're looking to add other shrimp, unless you feel like playing hunt and catch the shrimps. They get larger than neos and can easily out compete them for food.
You can find test kits online pretty cheap or take some water into your lfs for testing since most of them do it for free if you ask them I would def invest in a kit though
Sponge filters do not create a lot in the way of circulation and flow so you need to keep that in mind as well. They do however provide for a great food source for shrimplets due to their large surface area.