I actually didnt do any of those 3. My overflow is DEAD silent and the only thing I can hear is the wavemaker switching the pumps as a small click when they turn on. I do not have any pick but i will try and describe the best way I can for you.
First I drilled 4 holes in my tank. 2 drain and 2 return. I did not make any fancy overflow or create any fancy auxillary drain systems. all I did was used a basic bulkhead strainer on the first drain and NOTHING else inside the tank but the strainer. on the other drain is a 90 degree elbow turned horizontally to the level of the aquarium water level and drilled about 1/2" higher than the main drain. To prevent noise from sloshing I used nylon reinforced tube pvc as the drain into the sump from both. I also drilled and tapped an air tube in the 90 degree elbow (dry side of course) just like the bean animal type on the main drain. The final way I made it dead silent is by having the returns terminate about 6 or 7" under the water level in the sump. With the strainers there are no clogs to worry about and with where I keep my water level, the main drain has full siphon, and the 2nd drain has a very minimal trickle. even when the main return pump powered off, there is plenty of room to spare in the sump for any back siphon and draining. Now with me running a fuge, it is a low flow sump of about 300gph if that with a quiet one 3000 dialed down, My system is incredibly quiet and the only time I hear anything is if i am the only one home and standing right next to it- just a slight trickle of water kind of sound from the water going over the baffles, and thats with an open bottom iron stand with eggcrate being the doors lol (don't have a full time job yet so i can't afford to buy or make an actual wooden stand) The good thing about these drains is there is no light or space obstruction and even with some macro algae getting stuck in the strainer, I have had NO issues at all with water flow or noise, even with the second drain having water go down it there is no noise! I love it! I will add tho that the air tube is only utilized to get rid of the air bubble to create a full siphon, after that I clamped the air tube closed or submerged part of it otherwise it will suck air down the tube and you will get bubbling in the drain section of the sump and that can be a bit noisy. The only downside is that during water changes, I usually have to clean off a little bit of gunk from the strainer but that is easy since they just unscrew from the threaded Bulkhead. Hope this helps. Btw if you have any questions or want some pics (i am away from my camera at my in-laws right now- will be able to get pics tonight) just shoot me a pm and i will be more than happy to help.
One last note, if you don't mind a little extra maintenance, you could use a clear bottom overflow on your beananimal style overflow to allow light access to corals without much interruption in PAR or space. It would allow you to set some rock along the back wall and grow stuff under the overflow, only downside is that you would need to occaisionally need to scrape off corraline or algae from the inside of the overflow. Hope this helps!
