Bulkhead Question

[jvswan]

I'm a newbie to this whole saltwater reef tank business, having recently been introduced by a buddy. I found a pretty neat Japanese aquarium from a company called Nisso. It is a glass tank, about 45 gallons, with rounded corners. Pretty neat. Anyway, I've decided to drill the back of the tank instead of using a HOB overflow box. I'd like to set up the overflow using BeanAnimal's silent and failsafe overflow system (with the return on the opposite side of the tank, through the overflow box). I'll drain my overflow to a 10 gallon skimmer/sump arrangement.

I have a question about the bulkheads I should use. I know I need to match the return flow with the overflow. I figure that it would be easiest to set up the overflow first, then get a pump that will move less than the maximum capacity of the overflow design. So, I don't know what size bulkheads I should install. BeanAnimal's design has two overflows (a siphon and an open) plus an emergency overflow. The siphon handles most of the water for the system, but the open has to take a little, as well. I'm wondering if I can get away with 3/4" bulkheads or if I need 1". Or, does it really matter much? I'll be honest, I'd rather go with the smallest bulkheads I need for adequate water moving through the system. I suppose I'm hoping that I only need one size of hole saw for the drilling (I'll spend the extra $15 on a better skimmer

My other bulkhead question is about the style of bulkhead. I can't seem to find the difference between slip and threaded bulkheads. Does it have to do with how the plumbing is attached to the bulkhead? I can imagine threading an adapter into the bulkhead, but what is a slip bulkhead? Does the PVC pipe just stick in there? Is one better than the other?

So, what size and what kind of bulkhead should I use with my tank?

Thanks in advance for your advice. This is really a great site and I'm eager to get my tank up and going.

 

[Roy G. Biv]

Slip vs threaded is the part of the bulkhead that is IN the tank. Slip just slides in like a PVC pipe to an elbow. Threaded is threaded. If it is in the tank you dont need to glue it or tape it. Friction will hold it.

To give you some prospective on the sizes. All my 20's and 10's have 1-1/2" bulkheads on them and they still have a chance to clog up or not handle the flow. Keep in mind, the bigger the better. You wont be sorry.

 

[boilermaker1]

slip bulkheads have smooth bores in the bulkhead so you can cement pipes into it. A threaded bulkhead is threaded, and you screw a fitting into it.

 

[Conesus_Kid]

Your bulkhead choice will depend on your choice of return pump. Figure out the flow rate of your return pump, then use this calculator to determine your drain and overflow size:

http://www.reefcentral.com/calc/drain.php

The slip vs. threaded is a personal preference. PVC attached to slip bulkheads need to be glued with PVC glue. Threaded bulkheads allow you to remove your plumbing from the bulkhead without cutting it.

Keep us posted!

 

[jvswan]

Wow! Thanks for the great info. Guess I'll spring for the extra hole saw and go with bigger overflow holes. The calculator (thanks for pointing that out to me, Kid) indicates that my system should have overflow diameters anywhere from .8" to .97", depending on the amount of turnover I want. I figure 450 to 550 gallons per hour. Does that sound right for a 45 gallon tank?

Thanks!

 

[Roy G. Biv]

Usually its 3-5 turnover. Try putting on polarized sunglasses and look at the tank. If you see a checkerboard pattern, you cant drill it. Normally 45's are ok to drill, but its better to be safe.

 

[jvswan]

Bulkhead Issue

Bulkhead Issue

Before I drill, I'll stick my laptop in it and check it with my polarized sunglasses. So, 3-5 times the tank voume is good for water turnover? So, that means I should set up my return pump to carry 135 to 225 gallons per hour? That sounds low... No?

 

[AZDesertRat]

Total turnover will be much higher than that but yo make up the difference with things like powerheads or a closed loop. The idea is to keep the velocity through the sump low so you don't carry microbubbles back to the display and you have a low enough flow for a refugium.
Powerheads like Koralias, Tunzes or Seios move a bunch of water very efficiently. A closed loop can be plumbed to return water wherever you want it with things like eductors or LocLine for returns.

 

[jvswan]

OK. So, low flow through the sump. Make up the difference with powerheads or a closed loop. Got it. I'll shoot for 250 gallons per hour through the sump. That will simplify things quite a bit. Then, I can rig the internal pumps and powerheads to put out at least another 300 or 400 gallons per hour of water flow.

That will simplify my bulkhead selection, then. Thanks for all the suggestions!

 

[AZDesertRat]

Just to give you an idea of flows. My system is a 100 gallon 60" long by 18" front to back and 23" tall with a 30 gallon long sump. My return pump is an Ocean Runner 3500 going into two 3/4" LocLines towards the center of the tank, they actually exit over the top of my internal offset center overflow. I also have a OR 3500 pump in a closed loop that pulls water from the back center of the tank and returns it via an Oceans Motions Squirt two way to each upper back corner again through LocLine so flows can be directed. I then have two Koralia K4 powerheads that can be pointed where ever I need movement.
This all equates to about 3500 GPH total so movement is a good thing. If you plan on having hard corals you will probably want more movement than 600 or 700 GPH, probably closer to 2000 would be best. Two Koralia K3s would get you up there pretty good.

 

[jvswan]

Again, thanks for the info. I'll work on a way to build up the total flow in the tank.