Return pump speed/size with a UV Sterilizer

[gordemer]

I have a 90 Gallon Reef Ready AGA Tank, and a Aquaclear 200 sump below the tank. My return pump is a Mag 7 that also passes through a turbo Twist 6X (18W) UV Sterilizer . I figure with about 4 feet of head going back to the tank and the 3 90 degree bends on the way back the flow rate is probably about 450 into the tank.

Is that too fast for the UV? Should I use a smaller pump? I would rather not have 2 pumps. I already have a mag 5 feeding my EV120 Skimmer in the sump?

What can I use to measure the flow rate?

Thoughts? Ideas?

Thanks
Phil

[melosu58]

Moved to Hardware and equipment discussion

[tecwzrd]

450 GPH is a bit quick for most UV unless you have a 36W unit. You can get a Tom Aquarium Flow Meter for $10 to check the flow.

You don't need two pumps, you could just T the connection and use ball valves to control the flow to the UV.

What kind of UV do you have and how many watts is it?

[loganj]

You can get a flowmeter for about $7 (I think) from Dr Fosters or Marine Depot that will give you an idea of what your flow is. I would split the return and valve both sides. That will allow you to adjust the flow through the UV on one side of the return and let the rest go back to the tank through the other side.

[tecwzrd]

Originally Posted by loganj

You can get a flowmeter for about $7 (I think) from Dr Fosters

Forgot about the one at the drs. It's on sale also for $5.99

[gordemer]

If I were to T it off the return pump, would the T at the output of the UV, cause a problem or the other end of the main tee cause backflow into the output of the UV?

[tecwzrd]

That's the point of both the flow meter and ball valve. Using two ball valves would be optimal but even one on the line going to the UV would be fine. Any excess flow that the ball valve restricts on the UV line would go to the tank and not cause any back pressure on the pump.

Still need to know the wattage on the UV. As I said before if it's a 36W then the flow isn't too fast and you don't need any additional plumbing.

If it's 9 or 18 watts then flow should be closer to 200-300 GPH through the UV for it to be affective.

[gordemer]

I understand what you are saying. Attached is a diagram of what you are talking about and what others have said. My question is in the diagram, the 2nd T out of the V (Its 18w) (yellow line on diagram. What stops the main pump flow (black line) for trying to go into the top of the unit.

[loganj]

Ok...you don't want to tee back into the return line at the top of the UV. You want to tee as in your diagram at the bottom (red line) and then come out of the top of the UV with a line that goes straight up to the tank. This will allow you to adjust the flow thru the UV. So, you will have two returns going to the tank. And the flow you currently have is too much for an 18 w unit to really be effective.

[gordemer]

That what I thought (about the 2 T's), I was just trying at all costs to not run another line back. The tank is a room divider so any lines I add are visable instead of going back through the drilled return.

[tecwzrd]

Originally Posted by gordemer

I figure with about 4 feet of head going back to the tank and the 3 90 degree bends on the way back the flow rate is probably about 450 into the tank.

I missed the 3 90 bends the first time. Each 90 degree bend adds about another head to the head height calculation so your Mag 7 is getting around 350-400 GPH by the time it gets to the tank.

Since the 18W Turbo Twist can handle up to 400 GPH to be effective I think you should be fine without any additional plumbing.

[gordemer]

Well, I think I am going to be doing abit of both.

I am going to switch all the return plumbing to flexible 3/4" tubing, put a T off the pump and a flowmeter, then have 2 returns to the tank, one from the main pump T and the other from the exit tube of the UV Sterilizer. My biggest challeng is hiding the tubing from the UV going back to the tabk, is it is a room divider and open on all 4 sides.

[tecwzrd]

Sound's good. You could put a return on each end of the tank and since it's a room divider construct two smaller walls on each end to hide the plumbing similar to the photo below.

[gordemer]

The main return is going back the through the built in overflow, its hiding the new UV 3/4" return that is going to be challenge.