DIY Kalk Reactor and Sump

[dick182]

O ring will work, just put it between the flanges and tighten securly.
You definitely want something to mix the kalk though have a look at his one :http://www.canreef.com/photopost/sho...cat=507&page=1
Also the reactor looks a little short, you don't want the powder going through, just the clear water at the top.