The height in the overflow chamber is also set by how high the the primary stub is. Can go from none (just the bulkhead) upwards. Advantage of running the water level in the chamber on the higher side is less waterfall noise into to chamber. The water will back up over the top of the primary a few inches but takes a little playing around, just dry fit the stub into the bulkhead (don't need to glue) so it's easy to remove to cut back if needed.

All standpipe can be straight. Don't know what you're planning on flowing but know my 2" drains with Dursos can easily handle 1000gph each and from the different calculators expect them to do 2000gph+ each.

You should............ otherwise you will be in my situation this morning with a snail stuck in your main overflow drain! :bad-word::2gunfire: Guess I got some work to do when I get home..

Your primary drain can be anything from a strainer fitting screwed directly into the bulk head, to a section of pipe, up to half way up the over flow. The bottom side of the primary drain, under the tank, should be plumbed down below your expected water level in the sump (with a gate valve). The emergency drain inside the over flow should be slightly higher than the operating water level of the tank. The bottom side of the emergency is left short of the expected sump water level (acts as the warning sound). The gate valve is used to restrict the flow in the primary drain, causing the water level inside the over flow to rise to just below the point where the water drains down the emergency. This means, in most cases, less than an inch drop into the over flow. I opted to plumb my primary drain half way up the over flow to make it easy to remove when cleaning. Don't glue or teflon tape anything inside the over flow as you want to be able to get that stuff out to clean, rescue fish, crabs, etc. Have fun!!!:biggrin:

Has anyone tried the Hofer Gurgle Buster? How has it compared to the durso or herbie? I was thinking of trying this.

Here's how my Herbie looks:
http://i27.photobucket.com/albums/c1...u/IMG_5561.jpg


http://i27.photobucket.com/albums/c1...u/IMG_5560.jpg

I like to have a trickle down the emergency drain. I find that there's a wider "sweet spot" like this. There's no additional sound since the surface tension of the salt water makes the bit of water going down the emergency drain stick to the walls of the PVC eliminating any dripping, gurgling or splashing.

I've completely shut down the main drain with the ball valve and the emergency drain handles it without issue. Once the amount of water exceeds a certain level in the emergency drain then I start hearing the telltale gurgling and splashing.

The Hofer is the sort of the same idea as a Stockman or Durso in that they draw in along air with the water. What makes the Herbie silent is no air is mixed in.

Ok, so I pretty much got the idea of the Herbie down pat now. Thanks guys.

Now that Im a vicarious expert on Herbies I got another query; where exactly is water getting oxygenated if the Herbie doesnt mix air in the drain pipe with the water in a turbulent fashion?

I thought maybe this would occur in abundance in the skimmer with millions of micro bubbles, is this an accurate guess? Or do I need to worry about oxygenating my water somewhere in my system if Im running a Herbie?

Also, I think I'm 99% sure Im running a Herbie now, whereas last week I was 80% sure I was running a durso haha.

skimmer, surface agitation, water dropping into overflow