Plumbing uv help.

[svester]

I have the 55 watt and the 90 watt 3 inch

 

[AJsReef]

The 90w is rated at 650 gallons, I’m assuming your total volume is probably around 250.

2800/650=4.31 suggested turn over, 4.31x250 would mean you should push 1077 GPH for the max recommended flow at 30000 μW/cm2 (algae/bacteria).

I couldn’t find a chart with Protozoa rating published by Lifeguard. Making assumptions you’d want something in the 180000μW/cm2 range. Which would have you running the 55w 1/6th of recommended GPH or 350 GPH.

Which theoretically nets you coverage for both common types of UV installation. At a total return rate of around 1,425 GPH or almost 6x turnover. The 350 GPH pump will be easy but you may have difficulty pushing 1077 through a UV depending on head pressure and restrictions. These manufacturers engineer units with pools and ponds in mind where 2-3” plumbing and no head is the norm. Much easier to hit the flow rates.

Another thing to think about, I’m not sure what your tank temp is usually at. In just running my 80w UV 24/7 I gained a whole degree on my bottom end. So an additional 145 watts over 24 hours may push your temps relatively high.

 

[svester]

Thank for the information

 

[defasum]

Are you not going to end up with air traps in the UV chamber? I had this problem when I installed mine horizontally. I had to change it to vertical with the input on the bottom so the air pockets get pushed out.

 

[AJsReef]

Are you not going to end up with air traps in the UV chamber? I had this problem when I installed mine horizontally. I had to change it to vertical with the input on the bottom so the air pockets get pushed out.

Assuming the inlet/outlet are facing up the water flow clears all air from the pipe. It’s only an issue if they are facing downward as the uv body would become the highest point.

 

[svester]

I redone plumbing, after suggestions

 

[Sean Clark]

Looks cleaner... But... maybe consider eliminating the input ball valve and replace it with your gate valve. No need for redundant valves. Just my opinion.

 

[svester]

Revision #3. I think I final have it.

 

[AJsReef]

Looking good! Where the top union connects to your bulkheads do you still have a straight run for a few inches? Ideally you want 5” of straight pipe on either end of your flow sensor

 

[Sean Clark]

Tripple check that you will have access and enough room to pull the bulb out with the UV installed where ever it is going to be to make service easy.
Speaking from experience here. ;Facepalm;Eggonface

 

[svester]

Look twins, the 55 watt will run at or around 300 GPH and the 90 watt between 1000 & 1200 GPH. What do you guys think?

 

[Sean Clark]

I only run one with an adjustable pump, but I like the concept of running two dedicated units.

 

[svester]

If I used a COR 20 could I do that? Run uv#1 for a few hour at 300 GPH and then run it at 1000 GPH for a few more hour. Would the apex software be capable?

 

[Sean Clark]

If I used a COR 20 could I do that? Run uv#1 for a few hour at 300 GPH and then run it at 1000 GPH for a few more hour. Would the apex software be capable?

Yes you could use a COR pump and Apex to do that. My thoughts is that hopefully you are only trying to fix one thing at a time. So I adjust the flow to suit the problem. 99% of the time I am running it slower.

 

[DopamineKata]

That flow seems super high. I know my pentair 80w recommends 2700 GPH but that’s on a 600 gallon system which works out to something like 4.5x turnover which would only be 900 GPH on a 200 gallon system.

Unless you’re going with a very large AC pump I don’t know how you’d hit 2700 GPH on a return line

Isn't the flow for UV just based on what you're trying to kill? Tank size should be irrelevant.

 

[AJsReef]

Isn't the flow for UV just based on what you're trying to kill? Tank size should be irrelevant.

No, flow is based on desired contact time (exposure) in μW/cm2. Tank size is certainly relevant.

If a unit is rated for a 650 gallon system and needs 2800 GPH to get the correct exposure. A closed system that has less volume would have greater exposure at the same flow. In other words, you calculate the rated turnover for the the desired contact time and work backwards as above.