Help Me size a UV sterilizer

Caseyz · Oct 23, 2020

Looking for anyone experienced with UV Sterilizers to help me size the one on my tank. I have watched the BRS series and done quite a bit of research but am getting contradictory info. My tank will be a 210 with a 60 sump so a total water volume of 270. I plan to run the Sterilizer on one of my return pumps which will be a Vectra M2 so I can control the flow rate. I will have a max flow rate of ~1200GPH at the planned head height and can dial it down from there. I was looking at a 57 watt unit on BRS which specified a flow rate of 1066GPH. However when I looked up the instructions from the manufacturer they say a flow rate of 1200GPH is recommended for reefs on their 25 watt unit and that the 1066GPH 57watt unit is for fish only. I am planning on SPS with some fish so I want to make sure I am sizing this properly. From what I have read it looks like I should probably go with the 25 watt unit and run the 1200GPH flow rate and then if I am trying to kill fish diseases run it at a slower flow rate of maybe 600-480 GPH.

It is my understanding that a UV Sterilizer can do two things, control for bacteria like dynos or it can be used to control fish diseases at a slower flow rate. Assuming my research is correct, the 25 watt unit at 1200GPH seems to be the right answer and that I could also use the unit to decrease disease populations if I choose to run it slower while taking the risk of killing some beneficial bacteria at that speed. This is a totally new build so I can do anything, I just want to make sure I get it right the first time. Thoughts? Manufacturers info in the image below.

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ca1ore · Oct 23, 2020

Does your tank have a naturally occurring planktonic food source (the answer is invariably no)? Are you adding live plankton (the answer is usually no)? I assume 10 gallons per watt per hour for sterilization and tank volume through the UV 2-3X per hour. In my case, that means the TMC110.

Uncle99 · Oct 23, 2020

I’ve just used the 128 Jebao 55watt UV for a couple of years on my 180 with 50 sump.
Running it at 800gph, water of course, crystal clear.
Kills algae/bacteria only in the water column.

TvanB1 · Oct 23, 2020

I have an 80 watt AquaUV on my 150 mixed reef running @ 450-500 GPH.
My friend has a 225 and runs a 120 watt unit running @600gph.
Neither of us have experienced any disease since adding them.
Im planning on adding another 40-80 watts in the near future.

Steve Justis · Oct 24, 2020

I have a 160 watt on my 130.4 water box (FOWLR)and a 120 watt on my red sea pen 500 (Reef), both are from aqua ultraviolet and could not be happier with the water clarity and lack of parasites, my advice is go bigger than you think, if you can fit the unit in your space.

Caseyz · Oct 24, 2020

ca1ore said:
Does your tank have a naturally occurring planktonic food source (the answer is invariably no)? Are you adding live plankton (the answer is usually no)? I assume 10 gallons per watt per hour for sterilization and tank volume through the UV 2-3X per hour. In my case, that means the TMC110.

Thank you for the response. I have seen the 10 watt per gallon quoted in a couple of places on this site. Is there any research or articles you could point me to around that?

ca1ore · Oct 24, 2020

Some good articles here:

UVC Sterilization | How Aquarium & Pond UV Sterilizers Work

Information how a TRUE Aquarium, Pond UV Sterilizer/clarifier work. Category A, B, & C Sterilizers. Affect on green water, disease prevention, & Redox

www.americanaquariumproducts.com

By the way, comments like ‘I’ve been running UV and had no disease problems’ really aren’t terribly instructive. Correlation is not causation .... even if most people fail to understand the distinction. I think it’s reasonable to assume that a properly sized UV can help to manage disease, it will not prevent it.

ichthyoid · Oct 24, 2020

Much, if not most, of the research that went into UV treatment of water, was based on drinking water applications. That means a single point of contact application, not the recirculating systems we have.

The 90,000 uW/cm^2 number is based on a 99.995% kill rate of Ichthyophthirius. The numbers for cryptocaryon irritans are typically stated many times higher. These are anecdotal, or extrapolated from other studies based on morphology differences and are suspect.

FA164/FA164: Cryptocaryon irritans Infections (Marine White Spot Disease) in Fish

University of Florida, Institute of Food and Agricultural Sciences Extension outreach is a partnership between state, federal, and county governments to provide scientific knowledge and expertise to the public. The University of Florida (UF), together with Florida A&M University (FAMU)...

edis.ifas.ufl.edu

Healthy fish have some immunity to infection. So if we either quarantine, or prophylactically treat them, appropriately before placing into a reef tank, the UV is being used to help maintain that health.

I have a 25 watt Aqua UV Classic for a 135 gal volume system. I would follow the Aqua UV guidance and probably use a 40 watt unit on your size system, based on flow. Just know that the 40 watt bulb is longer so consider that into the plumbing layout.

I would also prefer to not run a UV at night on a reef system, as that is when planktovores/pods are active. So program the Apex to turn it off (if available). Cutting back the skimmer, if possible, for the same reasons may help. Though the gas exchange it provides at night helps keep pH up, so wouldn’t turn it off.

Regardless of what the planktovor population may be, that is likely partly due to factors we control & my thinking is that we should do whatever we can to encourage their viability.

ID-Reefer · Nov 29, 2020

Curious on thoughts/befits of running a small UV sterilizer on a larger tank. I have a new unused 15 watt UV and a 243 gal system. Thinking it would just be a small preventative measure added to the system. Plan to also use an oxydator.