I have a red sea reefer 170. I got it used and it was missing the plumbing and sump. I made a new DIY sump and got a plumbing set from red sea. The plumbing has 2 overflows, the main and the "back up". The main overflow tube has a slip over "silencer". When I put the silencer on it makes the main drain taller than the back up. Is this how it is supposed to sit? It looks like it would almost sit above where the waterline would be. I posted a couple photos in the front on view you can see about a 1/4 inch of the top of the silencer thru the overflow screen.