Hey so I'm going to post an update on this thread just in case anyone is having a similair problem and searches for threads about the aqueon evolve.
So the filter that came with my evolve 4 continued to make a horrible racket the whole time I've had it. I tried running it in a bowl of water in the sink to flush it out thinking that something was stuck in the motor- but nothing changed.
I searched and searched online for an internal filter that would be able to fit inside the sump in the back where the old filter was located, and one that would hopefully be able to connect to the ouput spray bar as well.
I came upon an Ovation 210 on thatpetplace.com Ovation 210 Submersible Filter - Up to 15 gal. | thatpetplace.com
and ordered it because the dimensions and the shape seemed right. It just came in today and with a little mixing and matching of the output tubing- it works perfectly! Its so quiet compared to the aqueon pump that I cant even hear it running. Another thing I like about it is that its not blowing my fish and sand around like the 125 gph
aqueon pump (for a 4 gallon! seriously??). It is 53 gph
which is a little more than 13 cycles of the tank volume per hour, and its gentle enough for betas with long fins. I hope anyone having as much trouble as I did with this tank finds this thread!