I recently got a small (~1/2 gallon) open ecosphere as a gift from my parents for college, and it has around 15 shrimp. I wanted to make it more diverse/lively by adding some small tankmates, and after some research, decided to add a horned nerite snail and MTS. Of course, no one is selling either individually, so long story short I now have 2 MTS, 4 HNS and 15 opae ula in my half gallon sphere. Following this, I worried I might've thrown the nitrogen cycle out of whack and bought an algae ball and macroalgae from here. Overall, it looks really nice. The snails are adorable roaming the glass, and the shrimp have fun playing with the ball, but I have a few concerns about this setup.
After a few days with the snails, I noticed a clear reduction in the visible algae on the substrate. In the image I'll attach, the bottom still looks pretty green, but trust me it is a definite decrease.) So, I've been wondering if this is going to be a problem or if it's just a matter of aesthetics. Will the combined demand of these animals exceed the algae/biofilm's ability to grow? Was it a mistake to add any snails, let alone six of them? On a separate note, is the macroalgae I added going to outcompete the algae they need to eat within the confines of this small system?
I really don't know what I'm doing, so if anyone more experienced than me with this type of thing could weigh in, any questions/advice/reassurance would be greatly appreciated.