• Looking to buy a cephalopod? Check out Tomh's Cephs Forum, and this post in particular shares important info about our policies as it relates to responsible ceph-keeping.

Overflow Q


O. vulgaris
Mar 25, 2004
what is the GPH of a 1 inch hole for a side drilled overflow? I drilled my tank with a 1 and 1/4 bulkhead and it can not handle my 700 gph pump. it oveflows the tank so im adding another? I was just wondering if anyone knows the GPH of a hole about 1 inch in diameter?
I dont think that there is an exact way to answer what the GPH will be... but you are doing the right thing adding another hole. My large cuttle tank when i had it, had three 1" holes on the side panel and that was a 600 or 700gph pump
ok yea cuz i think i am gonan throttle my pump down too so it seems like it will work if the mesh coevring the holes doesnt slow the flow too much.
Okay, also watch for the octopus blocking the holes, thats another reason i had three in the first place... Spread them out :smile:

Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.