Lovely pretty tank, we have crossed posted......
The cherry shrimp may even adapt to the new water as they are hardier than the caridinia. I see you have some moss, moss ball and plenty of soil.
I think you have the same filter as I use (I have 2 per 30L tank). If they are the same, I permanently remove the bottom plates, this means there is more sponge area for the shrimps to graze on and more filter area as well , and when you want to wash the sponge you just turn the filter 120 degrees (anticlockwise in your case and still attached to the glass) pull out the sponge, rinse it, and reverse, takes less than a minute - you don't even need to turn it off or take anything apart as the top end stays under water etc. Sponge needs to be tightly fitting in place so no shrimp can get inside and the sponge doesn't just drop out of coarse. Your glass though may not be deep enough for you to turn it through 120 degrees?
Simon