25 watt aqua uv sterilizer flow rate

[Keeper5221]

I purchased a 25 watt uv sterilizer for my 40 gallon display i thought i oversized it but apparently Pentair recommends running 79 gallons an hr for 25 watt uv which worked out well for me as thats in the 1-2 times an hr range ive seen people mention for parasite management but aqua uv recommends 400 gallons an hr minimum which is really fast compared to literally everyone else. My question is will the aqua uv get damaged from running the water through it so much below the recommended minimum ? Im guessing it should be okay cause i see alot of people buying the aqua uv but running slower rates. Would like some confirmation on anyone running a slower rate than minimum recommended though. Also if anyone can confirm that the flow rate will work for what im intending that would be awesome. I do plan on using my return pump to push the water through the uv sterilizer straight from the sump back to the tank, it is a dc pump so i can speed up or slow the flow if needed. Right now the flow of the pump is set to 120 GPH which after head height and running through uv should be somewhere between the 79-130 GPH recommendation of pentair.

 

[ca1ore]

I have not used that particular model, but on the ones I have owned, I always ran them below the minimum flow ranges. So far, no apparent damage. I have never seen this explicitly stated, but I always assumed that the water circulating through the unit serves to keep the quartz sleeve cooled. Running an UV dry is a bad idea, but I would think even slow flow would meet the cooling need.

79 gph across a 25 watt UV is around 3 gph per watt - more than sufficient for parasite control. I have always targeted something below 10 GPH/watt. My current unit is 55 watts with 400 gph.

 

[The_Paradox]

I would not get too hung up on flow rate. It’s total dose that matters not velocity.

 

[Keeper5221]

I have not used that particular model, but on the ones I have owned, I always ran them below the minimum flow ranges. So far, no apparent damage. I have never seen this explicitly stated, but I always assumed that the water circulating through the unit serves to keep the quartz sleeve cooled. Running an UV dry is a bad idea, but I would think even slow flow would meet the cooling need.

79 gph across a 25 watt UV is around 3 gph per watt - more than sufficient for parasite control. I have always targeted something below 10 GPH/watt. My current unit is 55 watts with 400 gph.

thank you thats what i thought aslong as water isnt going still in the uv it shouldnt overheat, i may up the flow to 140 gph if aiming for under 10gph/w has worked out. One more question about mounting the unit , if im going to be mounting it horizontally should i tilt the outlet so that its slightly higher than the inlet so that any air that gets into it is forced out or should i just have it level.

 

[ca1ore]

Tilting the unit so it can more easily purge air is always a good idea. I do keep mine horizontal but use my Apex to delay UV turn on until the pump has been running for 30 mins so there's plenty of time to purge air.

 

[dadnjesse]

I have the Aqua 57 watt been running for 5 years. I noticed light coming through the case and called support to ask about the warranty. He had me sent pictures and the pump I was using which was a sicce 1.5 357 GPH. He said the warranty was 7 years and I was denied for too small a pump. He told me I should have at least 1000-3000 GPH pump. The website does say 355-1066 GPH. There was also another person that had a thread about being denied a claim for the Ballast that was blamed for too small a pump. When I took mine apart to find the serial number the housing crumbled in my hands.

 

[Keeper5221]

The 25 w version recommends max flow of 1200gph the dc pump i will have running it is a 800 gph pump , i dont think they can fairly claim too small pump size when they say to run it at 400 gph for parasite control. So i should be good on that end. Thank you for the experience sharing though ! I tend to oversize any equipment i purchase and just turn things down incase i do decide to upgrade in the future to a bigger tank i can use pretty much the same stuff.

 

[gemipit]

I would not get too hung up on flow rate. It’s total dose that matters not velocity.

I’d be interested in knowing how to figure this. I installed the same pump as the thread creator on my redsea 625 (170 gal total system). I bought a DC pump that is 3200 gph and installed a Neptune 10 flow meter (I know it’s not that great everyone says). The pump is supposed to put out 2250-2000 gph at 5-7.5’ rise. My rise may be at 4.5’ however the plumbing has a few elbows and what not. The problem is I’m only getting 400gph at full speed on this pump according to the flow meter. The manual calls for 1200 gph for a reef environment and 400 for a parasite and disease method. What can you tell me or help me with when it comes to total dose? How do I figure that out or make sure I’m not nuking my planktonic food supply for my current and future reef? TIA