Sorry for the issues you are having with your Gyre. The pumps do have more drag when first put into use that does create noise along with the polishing of the ceramic contact points. When ramping up and down it will be most noticable. If you feel the sound is abnomal then I suggest taking the pump apart to make sure there is no broken or missing parts. Most common issue are the bushings are not present or have been stripped, the propellers are placed on backwards and the cages placed on backwards.
1. Please make sure that with the cages removed with one hand hold one of the propellers, If the opposite propeller rotates, you either have a missing or stripped propeller bushing. http://d.pr/i/10tCm
2. Please make sure the blade of the propeller is facing the front of the pump. http://d.pr/i/15D6C
3. Please make sure that the cage marked A is on the left side and the cage marked B is on the right side. http://d.pr/i/luYI
Or watch this video here which covers these items in more detail: http://blog.coralvue.com/maxspect-gyre-step-step-assembly-advanced-troubleshooting/