Need advice 180 gallon build

[dieselfish89]

So I have a 180 gallon marineland tank and am wondering. Is 36 gallon sump large enough. I have the option to put a second sump with my main one as a refug. Any advice help full old system has a 90 gallon QT tank and 150 gallon sump but has to down size.

 

[Foooz]

I just placed a 55g under my 180. I wished I had went with a 75 and still may when given the opportunity. To answer your question a sump is not necessary, very good to have but not necessary, so 36g is better than nothing. The question is what do you plan to have in the sump? You may run out of room quickly with skimmer and other equipment in a 36g.