Gate Valve before or after my UV

  • We are currently upgrading MFK. thanks! -neo
T

timelessr1

Feeder Fish
MFK Member
Aug 25, 2011
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How bad would it be if i put a gate valve right after my pumps return but before my UV sterilizer? the pump is a Reeflo snapper, and the sterilizer is a Aqua UV Classic 57. How would the sterilizer really know if i throttled the pump back just slightly? or should it def. be after the UV, in order to keep the water in contact with the light longer?:nilly:
 
I would think putting it first would be best. The best way to ensure the UV is working correcly is to regulate the water flow to within the best parameters of the unit. The slower the flow the better the UV will work!
 
I agree that the slower the flow the better....but if i put the gate valve after the UV, the flow would be slower also..but some UV sterilizers recommend not restricting their inlets....hmmmmm
 
Before or after makes no difference. Regulating 100 gallons going in will get 100 gallons going out. Regulating 100g coming out will require 100 gallons going in. Flow rate does not change before or after.
Depending how you position the UV, restricting the inlet may partially fill the chamber getting you less UV contact. UV should always be installed so it is always full of water.
 
kendragon said:
Before or after makes no difference. Regulating 100 gallons going in will get 100 gallons going out. Regulating 100g coming out will require 100 gallons going in. Flow rate does not change before or after.
Depending how you position the UV, restricting the inlet may partially fill the chamber getting you less UV contact. UV should always be installed so it is always full of water.
Click to expand...

But if i put the gate valave after the UV, then that will guarentee that the sterilizer will always be filled with water since the plumbing behind the valve will have a higher pressure then after the sterilizer.
 
timelessr1 said:
But if i put the gate valave after the UV, then that will guarentee that the sterilizer will always be filled with water since the plumbing behind the valve will have a higher pressure then after the sterilizer.
Click to expand...

Depending on how you position the UV, that is true. Realize you are subjecting the UV to some pressure. Cheap UVs leak under pressure. If you got it standing vertical with water going in from the bottom and out the top then no valve is required to ensure a full chamber. When placing horizontal inlet and outlet should be plumbed to prevent any air lock. In the event of an air lock, a regulating valve will not help.
 
I think your system would do better with the UV branched off of your return line.
You would still have full flow from your pump and be able to control the amount diverted to the UV.
 
You should not run your UV in line. Run it branched off of your return. If you run a T or a Y with a ball valve, and a Y on the return to the main return, you'll be fine.
 
What is the main reason for running it branched off from the main return? The pump I'm using is a Snapper Reeflo....which has about a 1700gph. the UV is good for up to over 3000gph...so if I'm putting about 1000gph through the UV ( which uses a 2 inch body , and i'm using 1 1/2 plumping) it would be easier to keep less plumbing and keep it in line to the main return. I'm hurting for space under the tank due to the sump and external pump since the stand is only 30"X30"

This is the UV im using

http://www.aquaultraviolet.com/products/uvsterilizers/classic/57watt


The UV is going to be laying horizontal, but the inlet and outlets will be facing down, this configuration allows much easier change of bulbs for maintnence. It would be easier if the gate valve was right after the pumps output and before the UV....but thats why i'm askking if its detremental to have the valave after the UV in oreder to keep back pressure in the UV which will in turn cause the UV to always have water in it when the pumps running...but when the pumps off...i can unscrew the top of the unit and remove the light without haveing a gallon of water spill out!
 
UV is good for up to over 3000gph

That rating is for the housing, not how the UV will function.

At 57 watts, you could push 570 gph through it and be assured of max benifit.
The rate you propose to run, I`m not even sure it could control algae.
But Hey,
It`s your system, do it the way you want.
 
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