Don't worry too much about your Nitrate levels.
Its is perfectly fine at anything below 40ppm.
In fact the Nitrate tests can be pretty inaccurate anyway due to the 2nd bottle of reagent solution, needs to be shaken really hard or until it feels like your arm is going to fall off!
The true level of Nitrate may be completely different to what the test says.
So not too big a deal to worry about as doing weekly water changes of at
least 25% will help keep nitrate levels under control really.
Adding stem plants like Elodea for example can be pretty good for keeping Nitrate level pretty low, as these are good at absorbing nutrients from tank water.
Your fan shrimp will be fine as long as you continue to feed your fish, leftover food or tiny nutrients from the food itself will drift off into the water, these shrimp are pretty good at finding foods you don't even know is in the tank
An algae wafer every now and again will be a nice treat for all your shrimps.