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View Full Version : DIY Spraybar ... HELP!


ufans
03-18-2004, 09:45 AM
I have been trying to figure out the best approach for building a spraybar that I can use to return the water into my aquarium from the sump and produce good water circulation as it enters the aquarium. Researching this has proven to be more complicated that I expected. Anyone have any advice?

Here is what I have been working with... My return pipe is 3/4inch ID PVC (Schedule 40). My return pump is a Mag 7 producing about 500GPH at 4'. The pressure really isn't the issue since I just want to make the spraybar total the same diameter as the 3/4PVC.

The spraybar that I have been thinking about is a 3/4PVC pipe with holes drilled into it. So, the inevitable question is how many holes and what is the size drill bit to use?... Well... here is the dredded math...

3/4PVC = .75in diameter
.75 / 2 = .375 radius

Area of a circle = Pi x radius x radius
Pi = 3.1415
.375 x .375 x 3.1415 = .44177

Area of the 3/4PVC = .44177 square inches

If you don't want to increase/decrease the pressure of the water then the total area of all of the holes should be the same as the 3/4 PVC

4 holes:
.44177 / 4 = .1104 square inches
.1104 / 3.1415 = .03516
.03516 / (.375 * .375) = .25 inch radius
.25 x 2 = .5 inch diameter
Use a 1/2inch drill bit and drill four holes... right?

Problem... The water pressure at a deeper hole is going to be increased and thus the higher holes may push out more water. But, the flow of the water is also going in one direction and the top holes will not push out as much water as the bottom holes since the water does not have the ability to stop,turn,and exit out of the holes. The bottom holes will push out the most water because the water current is backup when it hits the bottom/end of the sparybar and thus allow the flow to exit at the nearest hole; ie the bottom holes.

One may consider drilling the holes at an angle downward to help the current exit in the same direction and thus producing a more even exit out of the spraybar but all of your flow would be downwards vice horizontal which is the optimal situation.

So, if you don't just want a single exit that is the about the same diameter as your pipe then you either need to limit the number of holes, keep then close together, or do something more creative.

One creative solution would to put a T-junction when the pipe goes under the water and thus split the pressure allowing for the spraybar to be horizontal. That way the holes would get a better chance at being used to evacuate the water since the overall pressure is cut in half.

tendar
03-19-2004, 01:55 AM
Whoa way to much thought and math here for a spray bar. When I have done mine I just drilled some 3/8" here and there in it and caped the end. Since it is only a Mag7 the flow is not going to be that high anyways. If you really want to make more random add a SQUID to it and have 2 spray bars one on each side of the tank.

tendar
03-19-2004, 01:56 AM
Or feed the spray bar from both ends of and will get a even flow out of all the holes then.

gregb
11-21-2004, 08:05 PM
I made 2 rotating current makers using right angled garden irrigation fittings & 20mm tubing.