overflow question

[zeppelin]

I'm getting the overflow system drawn up before I get all the PVC and I've got a question. I have two 1" bulkheads for overflows. I am putting them one at each end of the tank (125 gal. High). Is there any reason I shouldn't run them into a 2" "T", and just run the 2" down pipe into the sump? I would put a ball valve on the 2" PVC, after the "T" for shutoff. Just want to make sure there isn't a reason to keep the overflows completely separate all the way to the sump.
Thanks
Larry

 

[zeppelin]

I know........scroll down the board before you post a question that was answered yesterday!
Still........any additional input would be appreciated. Just trying to cut down the amount of PVC I am running through the wall to the sump.
Larry

 

[jester]

The only thing I can see as a downfall from using a "T", is that the flow of water will not be smooth. See if you can find a "Y" or 90 degree bend that has an inlet "heel". This way the water will flow together smoothly instead of crashing together at a blunt 90 degree junction. Make sense?

 

[zeppelin]

Ya, that was the only thing I thought about as a negative. One of the only flow restrictions would occur as the two streams "crashed" into each other. The more water I was moving, the worse it would be. THe water is going to go from 1" to 2" just before it meets, so there will be some turbulence anyways with that transition. Maybe a "Y" with 1" 45s on the ends? That would end up to be a sweeping 90, or close to it, as the transition from two separate flows to one occurs. Thinking out loud at 5:00 a.m. here.
My tank is about 6 or so inches from the wall. I am planning on running hard PVC from the overflows, at approximately a 30-45 degree angle across, toward the center of the tank, and then running them into a 2" "T", then through the wall. The 2" pipe would then take a right for about 2 feet, along the wall, hit a 90 degree bend out from the wall, then another 90 down, into the sump. Biggest question I will need to answer is whether I have enough flow for two pumps. Want to run one full time and another to a spraybar on a timer.
With a 125 H, what size pumps does anyone recommend to get a good current going? I think I am going to run one pump 24/7 and one attached to a spraybar that kicks in when the lights come on.
I am using a 14 gallon Rubbermaid for the sump, and am considering partitioning it and using 1/2 or so of it as a refugium. Need to see how much room I need for two pumps before I decide how much I can allocate for the refugium.
Again, thanks for all the help. This is a definite P-R-O-J-E-C-T!
Larry

 

[broomer5]

Remember the old formula for figuring the area of a circle, that describes the ratio of the circumference of a circle to it's diameter ? ( taken right from Webster's Dictionary )
(Pi)x r2
Same for internal piping diameters and flowrates.
1" Schedule 40 PVC Pipe has 1.029" I.D.
1.029" diameter D, divided by 2 = .5145 radius r.
.5145 x .5145 = .2647
r squared = .2647"
pi = 3.14
3.14 x .2647 = 0.8312 square inches internal area of 1" pipe.
2" Schedule 40 PVC Pipe has 2.047" I.D.
2.047" diameter D, divided by 2 = 1.023 radius r.
1.023 x 1.023 = 1.0465
r squared = 1.0465"
pi = 3.14
3.14 x 1.0465 = 3.286 square inches internal area of 2" pipe.
It's pretty clear that a 2" pipe will handle a lot more water than two 1" pipes combined.
It's almost a factor of 4 times as much - because "flow" through pipes is always a function of "area" of the piping times the "velocity" of the water ( Q=AV )
Although in a gravity feeding drain - one would not expect the piping to be 100% full at any given moment. Gravity drains actually flow less than say a full pipe, that is under pressure, and is discharging to atmosphere.
But nevertheless, the potential, or flow characteristics between the two pipe sizes is somewhat constant. You can get approximately 4 times as much water moving through - when you double the pipe size.
Gravity lines flow best when not full, are slanted downward, and allow air to vent the entire length of the piping arrangement.
Makes them quieter with less entrapped air pockets to cause bubbles. Although if not vented, and running more vertical, it's possible to have water back up in the drain, adding some head pressure to the equation - and this in itself helps to increase the flow draining down to the sump. It's a trade off.
Going from two 1" to one 2" should not be a problem.
How you actually "plumb" the fittings, runs of pipe and such, makes it hard to predict how the actual water will behave while draining down to the sump.
If you do plan to install a ball valve ANYWHERE in this 2" line, you may want to consider using a 2-1/2" or 3" PVC ball valve.
Normally pvc ball valves are "reduced-port", meaning the actual hole in the ball is much less than the internal diameter of the same size piping. Unless you can find a "full-port" ball valve.
Restrictions could really mess this up - and all bets are off at that point.

 

[zeppelin]

WOW, Thanks Broomer!
I appreciate all the help so far.
Tank is starting to clear up after the sand dump Sunday. Topped things off with a bag of Southdown. Probably start the plumbing soon. Was going to start it this weekend but it looks like the family and I may be headed up to Cedar Point one last time for the closing weekend. Gotta hit those awsome coasters ONE MORE TIME! I'll update as I go. Going to try to remember to take pics along the way so I can document everything.
Later
Larry