Any familiar with this . . . . (a little long)

[nasotang00]

Last night I installed a sump that i made that consisted of a CPR CS50 overflow (300 gph) with a return pump that is a Rio2100. This took the place of a Magnum 350 canister filter. It is on a 55 gallon fish/reef setup. The problem that i am having is alot of noise from the overflow and a worry that if the power goes out that return pump will overflow that tank when the power comes back on. I have done the check about the sump over flowing and it won't. The water level in the sump seems a bit high and i know that the rio 2100 pump is rated faster than the overflow but where is the level of the sump water supposed to be. The system is up and running fine now. can i remove a little water from the sump to level it out? Also on the CS50 overflow, is the back "sump" portion supposed to be full of water or is the water supposed to be just above or in the middle of the bulkhead drain. when the water is half way it make a tremendous gurgleing noise.
Or should i just re-install the magnum and get a hang on prism skimmer for the tank. I know that sumps are supposed to add not just extra water volume but are able to keep a much stabler environment.
any and all help will be apprieciated.