Question on the Durso System

[Mike3]

I'm currently drilling the back bulkhead of my plex 180 with 2- 1 1/2 inch drains. I plan to expand to a 2 inch elbo and a 5 inch rise to the surface. I am only planning on cutting slots in the top of the PVC for water flow. Can you see any problems with this design? I plan to pump around 1400 GPH through these drains. The boxes that are fitted around the Durso pipes that are drilled in the bottom of tanks serve what purpose? I can not figure out what there function is other than restricting snails, fish, from entering the drain system?

 

[esmithiii]

The overflow boxes are designed to keep your whole tank from flooding when the power goes out. The idea is that water flows over the walls of the boxes and then goes down the durso stand pipe. If the power goes out, only the water in the box drains down to the level of the stand pipe. If you have a stand pipe and no overflow box, the whole tank will drain down to the level of the stand pipe, which can be quite low in order to get enough flow. My stand pipes are about 4-6" below the water line. If I didn't have the overflow boxes, my tank would drain like 45+ gallons in event of a power outage.

Can your sump handle that much extra volume?

I would not try it without the overflow boxes.

 

[Mike3]

Thanks for your help, but I still am a little confused. If your Durso pipe is below the water surface I can understand how your tank can be drained to the level of your Durso Pipe. But, on the other hand, my pipe will be level with the surface of the aquarium so I fail to understand how it will drain my aquarium. ?????

 

[Chaser]

I think what he's saying is that his water inakes are 4-6" below the waterline on his tank, so he has to plan to hold the 45 gallons in his sump in the event of a failure.

Since you plant to have your intakes near the surface you would have less water to worry about. The problem you may have is that inakes that high may not give you enough flow. Depending on the return pump you use, you may overwhelm your tank and flood it. (I did!!!)

 

[Mike3]

I understand that I will not have the waterflow that a Durso pipe that is below the water level has. What kind of flow do you think I can handle with the increased intake of 2, 2 inch pipes and a 1 1/2 inch bulkhead?? I have been thinking of drilling the bulkhead around 6 inches below water surface, won't that also help with water flow? Before I drill, I want to make sure I won't have problems later. I am getting rid of my CPR overflow box. I hated it !@!!!!!!! any advice will be appreciated, thanks.........Mike

 

[esmithiii]

Mike,

No easy answers here. The only way to get enough flow through the durso pipe (or any other for that matter) is to have it several inches below the waterline. To calculate the additional number of gallons your sump will have to accomodate to handle a power outage use the following formula:

L x W x D /230

where
L is the length of your tank in inches
W is the width in inches and
D is the distance from the waterline (when the pumps are running) to the bottom of the intake.

In your 180, if your standpipes are 4" below the waterline (mine are 6" in my 180) you would need an additional room for 30 gal. in addition to the water in the sump when the pumps are running.

Ernie

 

[esmithiii]

I failed to mention that I get around this by having a partition around each standpipe. When the power goes out, only the water inside the partition drops to the level of the opening in the standpipe. (The partition is the box you see around durso's standpipe. All Reef-ready tanks come with them pre-installed. If you are going to have your tank drilled, why not add a similar partition?

 

[Mike3]

Thanks for the help.....I had thought since my bulkhead holes were 6 inch below the waterline than I would have that pressure flow down. I guess I need the actual pipe below the waterline, not just the bulkhead holes.