8mm water exit hole on DOC 9015 skimmer?

[rwsunrx]

I'm just setting up my 9015, so my apologies if this is a dumb question. There is a small hole approximately 8mm in diameter located about 1.5" from the top of the skimmer housing. It is located on the back of the housing, i.e. the side opposite the Tunze logo. When I start up the skimmer, water comes out the output pipe as I would expect. But I also get a fair amount of water exiting this 8mm hole. Is that normal, or am I missing some part?

 

[crumbletop]

It is normal. See this post from Roger (scroll down to the bottom of the post):

http://www.reefcentral.com/forums/showthread.php?s=&postid=6205099#post6205099

 

[rwsunrx]

Thanks crumbletop. That's just the thread I needed.