Drain pipe size ?

[d-maz]

I'm in the process of upgrading to a 180 that has 1 1/2" drains that reduce to 1" at the bulkheads. Here is the thing I will get questioned on. I don't understand the high turnover rate and have had great success with my current 90 gallon SPS dominated tank with no more than 300-350gph return. I don't plan on putting a big return pump on my 180 and want to know if it would be quieter if I went with 1" drains all the way from top to bottom? Since I am not going to have a huge turnover, would the smaller drains have less air in them which should mean less noise? I'm trying to get the new tank as quiet as possible.

[danil]

First 1" overflow pipe is normal for 180g if you have two overflows. If you are into noise free tank you have to look into herbie type overflow. How much flow in sump you need It's up to you. Some like it slow others prefer fast. I would say rate it a more then your skimmer pump but not 10 fold :). If you will go with herbie type you will max out two 1" pipes around 1500GPH.
You can get DC pump with variable flow and use herbie type overflow. This setup will be noise free and flow rate can be changed in any time if you want to.

[d-maz]

I do have 2 overflow boxes and the drain pipes are 1 1/2" that reduce to 1" at the bulkhead. I tried the herbie on my current tank and could never get it failed in to were is was silent. I did think about trying it again on the new tank. Any tips on dialing in the herbie?

[danil]

Are you sure it was a herbie? In herbie the overflow is always under the water line so no air can possibly get in hence no gargling noises. There is no any tips to dialing in just adjust valve to keep overflow pipe fully submerged all the time. That's it.

Here is the link to check out.
http://gmacreef.com/herbie-overflow-reef-tank-plumbing-method-basics/