HOB overflow pump or drilled?

[AverageReefer]

Ill be moving my 30 gallon to my new house which has a 75g, the current 30 gallon has a overflow drilled in already, ill be moving in a couple days and i dont know if i should get the 75 drilled or use a hob overflow. My fear is that if the power goes out with a drilled hole, the sump may or may not flood. whats the pros and cons of both theese methods?

[cougareyes]

Properly sized sump will not overflow, a drilled tank is just cleaner looking.

[AverageReefer]

Properly sized sump will not overflow, a drilled tank is just cleaner looking.

What would be a properly sized overflow for a 75 gallon? Could i use my 30 gallon and leave approximately 5 gallons empty?

[mandarin_goby]

I think a 30 gallon sump would work great, but yes, you'll have to test the correct level for the sump by turning the pump off and seeing how full the sump gets (maybe fill the sump half way, then turn pump off). I used a Lifereef overflow for years with no issues with a Sicce 3.0 pump on my 40 breeder then 57 rimless. The Sicce 3.0 is also being used on my new drilled 75, it has plenty of power and is nice and quiet.

[cougareyes]

Figure my 90 using a 20g sump and when running the sump is about 1/2 full.

[aqua tech]

Drilled level the tank to sump water properly and it will never over flow