Switching from Durso to Herbie, are my bulkhead too high?

[madmark285]

The top of the 2 bulkhead fittings (1") on my 75 gallon tank are about 3 1/2" below the water line. For a Herbie drain, the main drain line (siphon) will be ~3" below the water line, most web sites recommend 6". The drain lines are 1" Sch 40 PVC.

I just got a Quiet One Lifegard Model 3000 Pump, max flow rate should be around 550 gph, I can turn down the output but unsure of the minimum flow rate.

Will a Herbie drain work on this setup with 3" between the main and emergency lines?

I could install a 90 elbow, pointed down on the main drain line to increase this distance, would that work?

Thanks

Mark

 

[Idoc]

I can't picture how your main drain line bulkhead only has 3.5" clearance from the water line. Is this a shallow frag tank?

The reason for the 6" depth of the main line is to get that much water above it to keep air from going into the main siphon drain line. This allows the full siphon to take effect and keeps the noise away.

Like this:

 

[madmark285]

Thanks for your reply.

It is a 75 gallon glass tank with a tempered glass bottom ie: I can't drill into the bottom of the tank. The original plan was for 2 Durso drains so I drilled the 1" bulkheads 4.5" (centerline) below the waterline on the back of the tank which gave me plenty of room. Unfortunately, I reduced my Durso drains to 3/4" pipe and all the water was going down one drain, majors problem so I decided to replumb the system.

My plans today, plumb it up and see if Herbie drains works as is. If this fails, I will remove and enlarge my custom overflow box and put in a downward pointing elbow on the main drain, this will give me the required 6".

Note: major frack up on my part. I hope this is OK but this is a freshwater tank and I should have came to reef sites from the start, you guys very strong on high tech systems.