UV Sterilizer Flow Rate Question?

[Declan O'Neill]

I added an Aqua UV Classic 25 watt UV Sterilizer to my tank Jan 1st. On Tuesday, I added an Apex Flow Sensor – 1″ (FS-100), so I could get an idea of how much water was being circulated through the UV Sterilizer.

Apex Flow Sensor is reporting 261.19 (Average Gallons per hour) and 266 Max.

I'm using a standalone Lifegard Aquatics Quiet One Pro 4000 to pump water through the UV
- Rated output 1022 GPH
- The distance from the sump to tank (head height) is approximately 4 ft
- The distance the water flows throw tubing / UV / Flow Sensor is approximately 7ft

Tank Size: 120 Gallon (48 x 24 x 24) + Trigger Systems Ruby 36 Sump. I estimate about 140 gallons of water in total.

The Aqua Ultraviolet UV sizing chart suggests for Marine Fish Tanks (No reef or Live Rock): A UV rated in the 75,000 (480 GPH) to 90,000 (400 GPH) columns will be the most effective at controlling fish disease.

Based on the Apex Flow Sensor, my water is cycling through the UV Sterilizer nearly 2 times per hour. But Aqua Ultraviolet suggest cycling the water about 3 times per hour.

Has anyone run their UV Sterilizer at a lower than recommended flow? Have you experienced any problems?

I'm considering buying another COR 20 if the flow needs to be 3 times per hour. However, if two times per hour is ok, I'd rather not spend money on upgrading the pump.

Thank you in advance.

 

[DLHDesign]

I'd think that a 2x turnover through the UV would be effective enough for general tank needs.

 

[Hermie]

There really is a science to it... but the results of fine tuning flow through UV are so hard to "measure" that IMO it's only worth following the general rule that slower is better. So if anything, I would say, buy a second UV unit hooked up in-line with the other instead of upgrading your pump. In my estimation, More UV wattage is more effective than faster flow through the sterilizer.

 

[Declan O'Neill]

DLHDesign, NotASpammerDude, thank you for the feedback.

 

[ReefHog]

Interesting reading.
http://www.americanaquariumproducts.com/AquariumUVSterilization.html

 

[ca1ore]

I think twice per hour is fine and you’re broadly at 10 GPH per watt which is what I typically aim for. Think of it as a balance between enough flow to sweep any nasties into the sterilizer and enough dwell time to eliminate them. I run about 1,000 GPH (off my siphon drain) through my TMC 110 unit.