Make sure you don't overfeed your shrimp.
They don't eat much & since you have less than 20, they won't require much other than the bio-film around the surface of the tank.
I would not recommend against buying any more Penn Plax type equipment. What you're using for filtration is a very OLD (20+ years) version of a sponge filter. I've seen their products before & I always dislike the quality of everything they create for the aquarium.
Their newer PPlax Blue colored HOB filters look decent though but I wouldn't buy it due to the amount of products I've thrown away from that company.
Honestly you would have been better off making your own DIY sponge filter. Hope you're not using the built in carbon/gravel type media that's included.
If you have time, take measurements of the temperature & the water parameters.
Just remember the more LIVE plants you have, the better off your shrimps will be & more hiding places for the fry.