HOB fuge and tank Overflow???

[lienSlob]

I am planning on putting a HOB fuge on a 20L i have planned. Either the AC300/500 style or a CPR Aquafuge style.

 

Do these require careful monitoring to prevent overflows? What if the power goes out and then comes back on? I am not sure how these work exactly from their descriptions and a family member who tends to my tank about 1/2 the time as a favor to me likes things as simple as possible.

 

Should I just drill a hole to the fuge box and put a bulkhead in?

 

Thanks in advance