Yeah I was going to because I did some research and keep seeing that done. How is yours? Im not set on doing that though. I think the main idea is to keep any small fish or snails, ect out of the plumbing but since this is a FOWLR with no snails, crabs or small fish (smallest is 4") I may not need it.

Not sure how the herbie works (haven't read up on it) But by the picture, it looks as though the overflow pipe for the herbie is only halfway up the tank. How high will it be in real life? If it is this low, you will have a lot of water draining into sump in the event of a power outage.

From the looks of your diagram, what you should do is just drill a hole in the sump for the skimmer pump. Then drill a hole in the refuge for the skimmer output. That would solve your problem.

Herbie works by using the gate valve to match the overflow gph to the return pump gph exactly. This then does not let air into the the plumbing and therefor is very quiet. To do this, the main drain needs to be a few inches underwater in the overflow. Or you can just use a strainer in the bottom, doesnt matter.

As for a power outage, I dont see how its much different than any overflow...It will drain until the water goes below the teeth of the overflow box and then water will stop flowing into the overflow and then can't possibly go into the sump anymore. So basically maybe an inch of water. Where the pipe is, doesnt make a difference.

Your idea for the skimmer is good. I may have to just put it in the sump though depending if I make my stand higher or not. If its not made higher, I would not be able to have the skimmer raised up so that the return feeds back down inot the refugium.

As untamed commented I would strain the overflow with a filter bag in the sump. Much easier to clean and will not effect the 'Herbie" (why isn't this called a Therlow)

Filter Bag

What would you use inside the overflow then?

Just slip it over the exit tube of the overflow. It's best to get 4 or 5 so as they get dirty your can through a bunch of them in the wash.

J

So do you mean I should have nothing inside the overflow over the bulkhead, just the filter sock in the sump?

Yup.

Oh yeah, I totally forgot about the overflow box! You are ok then :D Is the second overflow plumbed into the sump as well then too? it wasn't connected to anything in the pic.

How big are you GSP's? My ceylons are 1.75" without tail, so I won't be attaching my skimmer/refug for a while.

Oh ok. I had thought about doing that when I was drawing up the plans but when I looked at other peoples "herbie" style overflows, they all had some kind of strainers in the overflow. I like the idea of having the strainer (filter sock) in the sump instead because that seems way easier. Thanks for the idea!

What about flow through the sump/refugium? I still want to use a Sequence Dart for the return pump and another Dart for the closed loop. I think that would give the tank enough flow. I would prefer not to have to use any powerheads.