UV Sterilizers, which unit to choose and why?

[Aardvark1134]

Not sure where you got the aqua uv #s but from their own site the 57 watt is at 90,000 µw/cm2 (EOL) GPH: 1,066 meaning to get 180,000 it would be at 533gph it appears this is calculated with 100% bulb strength. Many brands use 80-90% for the calculation.



The biggest difference between brand ratings is if their flow rate is based on 100% 90% or 80% bulb effectivness.

 

[DJF]

Really nice write up! - question: I often see 3rd party UV bulbs cheaper than the manufacturers. Is there any difference in their light output or life? Most cases they are over half the difference and I’d be ahead changing twice as often-

 

[Jet915]

Yeah, I have a Pentair 40w for my 120. Works great but I did have to buy a chiller. I live in so cal so my chiller typically starts working in spring and summer. The UV probably increased my tank temp 2 degrees or so. I run it 24/7.

 

[le fou]

Not sure where you got the aqua uv #s but from their own site the 57 watt is at 90,000 µw/cm2 (EOL) GPH: 1,066 meaning to get 180,000 it would be at 533gph it appears this is calculated with 100% bulb strength. Many brands use 80-90% for the calculation.



The biggest difference between brand ratings is if their flow rate is based on 100% 90% or 80% bulb effectivness.

I was talking about the Lifegard 55 watt, no the Aqua 57 watt. Sorry for the confusion. I agree with your numbers for the Aqua 57 watt.

To get the same level of the Aqua 57 watt, you need to get a Lifegard 90 watt (since we get 2800gph at 30,000 µw/cm2, we need to decrease the flow by 6 to get 180000 µw/cm2 -> 2800/6=466gph), the Aqua 57 watt is 530 gph.

 

[Aardvark1134]

Here are the Lifeguard #s straight from an email where I asked them if the breakdown was linear.
"Thank you for your email. For the 120 Watt Pro-Max:
4,000 gph=30,000 uw/s/cm2
2,000 gph=60,000 uw/s/cm2
1,333 ghp=90,000 uw/s/cm2
1,200 gph=100,000 uw/s/cm2
1,000 gph=120,000 uw/s/cm2
667 gph=180,000 uw/s/cm2
500 gph=240,000 uw/s/cm2"

 

[mcshams]

If money and space are not a true concern, you can effectively obtain BOTH objectives of sterilizing protozoan/bacteria AND effectively manage algae control with a large enough UV light for your tank.

Protozoan control requires slower flow as a means to increase direct uninterrupted contact time with the UV light, essentially taking longer to sterilize those organisms than comparable algae. Algae control by contrast does not require as much "contact time" in a single pass, but becomes an issue of turnover, thus exposing your water and free-floating algae cells to the UV sterilizer.

If you look at specifications for a UV sterilizer, and calculate tank water turnover relative to your UV light size, you should find that you can achieve a slow enough flow to sterilize protozoan AND run enough water through to kill algae.

Take for instance my 90 gallon DP + 10 gallon sump (really running 80 gallons after rock displacement). Using data on PENTAIR 40W UV sterilizer...
The 40W bulb has the following specifications:
Specifications:
Max Aquarium Size: 260 Gallons
Algae & Bacteria Water Flow Rate - 943GPH/1574GPH (Suggested*/Maximum)
Protozoa Bacteria Water Flow Rate - 157GPH/262GPH (Suggested*/Maximum)

For algae, they are recommending that your maximum tank volume of 260 gallons is being run through 3.6 to 6 times per hour. (943GPH/260gallons = 3.6 and 1574GPH/260gallons = 6.06).

IF I use this bulb/sterilizer set up on my 80 gallons of net water in my tank, I only have to run this sterilizer at 144GPH to 242.4GPH to control algae based on MY volume of tank water. . By doing so, I have still run ALL my tank/sump water through the system 3.6 to 6 times PER HOUR... BUT with one added bonus: I have the water running slow enough to increase contact time in a single pass to fall within the recommended guidelines of 157GPH/262GPH to effectively treat Protozoa/bacteria which is based on CONTACT time.

IF you can do the math on your tank specifically, AND have the space/money to upgrade to a larger UV, you can do both. When my wife and I added ours, it improved the appearance and overall health of our tank overnight. We love it.

 

[cale0721]

Just installed an aqua UV 15 watt HOB today on my 75 gallon reef with a ruby series trigger sump. Looking forward to seeing the benefits. My reasoning for the add was to help fight bacteria and algae. I have some red dusting on the sand that disappears at night and comes back when the lights are on.

 

[Malcontent]

In a recirculating system, dosage is the same regardless of flow rate.

It then comes down to having enough watts for the volume of the tank and making sure the flow rate isn't too low. There's a point at which higher flow rates have the same log removal but below that point sterilization is less effective.

 

[Aardvark1134]

Except that has been proven not true Malcontect. They have shown that there are plenty of things you can kill on a slower flow through a sterilzer with x watts that you can not kill with the same exact sterilizer with 4x the flow. Example 8x flow at 30,000 will not give you the same killing power as 1x flow at 240,000 on the same sterilizer the faster does better on algae and weaker things while the high powered slower pass works on some diseases that the other won't. Multiple passes only are additive on killing power if they are plumbed back to back an inch or 2 apart. If you are flowing back into the tank and around again the extra passes from more flow are not additive in killing strength.
These 2 settings will have completly different outcomes on what they can kill and how much of it they kill:
Sample 120W UV
4,000 gph=30,000 uw/s/cm2
500 gph=240,000 uw/s/cm2

 

[mcshams]

@Aardvark1134 is correct. The uw/s/cm2 can be calculated precisely for flow and as such there are distinct advantages for some organisms to flow versus direct continuous contact time and while some organisms are susceptible to UV to the point that it would not matter that much, other organisms can be far more hearty and thus not being in the correct range would not effectively sterilize enough of the population to obtain control of their growth. Even diameter of the tube itself can affect the UV sterilizer overall effectiveness however most manufacturers have tested this and don't make 12 inch diameter UV lights for that reason.

 

[MarineREEFpassion]

With the recent buzz around UV Sterilizers thanks to a few videos from industry giants I have seen a lot more people talking about UV's. Naturally most people purchase what these industry leaders push / sell which is fine and dandy, but I suggest everyone do their own research.

When selecting the right UV you need to determine what it is that you are trying to control in your aquarium. Typically, most people select a UV to control either Algae (of various kinds) or parasites (of various kinds). Make sure you do not select a unit that is too undersized to do the job you are selecting the UV for. Also keep in mind selecting a very large unit could cause a lot of unwanted heat in your aquarium. UV's are essentially heaters that are on ALL the time unlike a normal heater that cycles on and off to regulate the temp. One other thing I see discussed from time to time is “part time usage” I have not personally done testing on only running a UV part time I.E. 12hrs on and 12hrs off, however Bulk Reef Supply makes suggestions that it is almost pointless and I tend to think the same.

One thing to keep in mind is the yearly maintenance cost for replacing O-rings, bulbs, seals, sleeves / liners (if replaceable). I also recommend checking around to make sure parts are readily available for the unit you are looking to purchase. What happens if the Quartz sleeve breaks? or the ballast goes out? can you buy those separately? What happens if you upgrade tanks and need to replumb it can you replace the end caps / fitting? No matter which unit you choose I highly recommend keeping up with the proper yearly maintenance to ensure your UV is always working optimally. Typically, after a year of use the bulbs output has been reduced by roughly 20-30% which is normally accounted for in the advertised rating of the unit but this is not always the case on cheaper units.

Of course keep in mind the overall size / dimensions of the unit. Will it fit where you need it to? Will you be able to remove it from your system semi-easily for its yearly maintenance? Does the unit come with mounting hardware or do you have to purchase that separately? Surprising most units do not come with a way to mount them. Do the fittings provide flexibility for different mounting options? What is the diameter of the housing? The larger the housing diameter the longer the contact time. The longer the contact time the better chances the UV will kill what you are trying to kill. Some companies use 2" housings some use 3"- 5" housing. Don’t get hung up on the input and output sizes as you can just reduce the fittings down to accommodate your current plumbing diameter. A 2” output can easily be reduced to 3/4'” pipe / hose (standard return sizing).

Keep in mind that the very components that the sterilizer is built out of (PVC) is also affected by the UV light. Most quality units are built out of UV resistant PVC, keyword is "resistant". Cheap units aren’t even built using UV resistant PVC. Some units have replaceable PVC liners protecting the actual housing. Some have lifetime warranties on the housings. Keep in mind most all warranties apply to the original owner with proof of purchase. Do you want to spend the extra time to replace liners yearly? or deal with possibly replacing the entire housing IF it should ever fail from UV exposer. I do suggest staying away from units not utilizing UV resistant PVC or units utilizing poor quality overseas PVC. As the UV exposure will quickly start breaking down the PVC and cause it to leech into your aquarium which can wreak havoc on your fish and corals.

Now, that is out of the way here is what "I" like and why "I" choose it. I choose the Lifegard Aquatics Pro-MAX high output Amalgam 90watt unit for my 300+ gallon system. Cost was $396, it is a high-quality unit, all replacement parts are available, has replaceable PVC liners unlike most units on the market. The power supply has a countdown day meter (kind of like a reverse hour meter) that lets you know when it’s time to service the unit (no other unit has this feature). I also really like how the input and outputs can swivel which makes the mounting and plumbing options extremely flexible. I also like the low yearly maintenance cost, the fact it includes hardware to mount the unit, and it has an Amalgam bulb which maintains its light output better than standard bulbs.

Below are some price comparisons on actual UV sterilizers, yearly maintenance cost and spare parts. I obtained these prices from Marine Depot, Bulk Reef Supply, and Amazon. Pricing and availability may change and you may be able to find better pricing if shopping around at pond supply shops, online lighting shops or even purchasing your yearly supplies during Black Friday sales. Also keep in mind there are many other sizes, options and suppliers, these are just some of the more common units used on larger aquariums.


Some of the more popular UV sterilizer's pricing.

Lifegard Aquatics Pro-MAX 55 watt 3" $274
Lifegard Aquatics Pro-MAX 90 watt 3" $396
Lifegard Aquatics Pro-MAX 120 watt 3" $643

Pentair Aquatics 40 watt $399
Pentair Aquatics 50 watt $739
Pentair Aquatics 80 watt $779

Aqua Ultraviolet 40 watt $436
Aqua Ultraviolet 57 watt $476
Aqua Ultraviolet 80 watt $756



Some of the more popular UV sterilizer's yearly maintenance cost.

Lifegard Aquatics Pro-MAX 55 watt 3" $74 Includes bulb, O-rings, PVC liners / sleeves
Lifegard Aquatics Pro-MAX 90 watt 3" $84 Includes bulb, O-rings, PVC liners / sleeves
Lifegard Aquatics Pro-MAX 120 watt 3" $109 Includes bulb, O-rings, PVC liners / sleeves

Pentair Aquatics 40 watt $108 includes bulb and O-rings
Pentair Aquatics 50 watt $100 includes bulb and O-rings
Pentair Aquatics 80 watt $110 includes bulb and O-rings

Aqua Ultraviolet 40 watt $95 includes bulb and O-rings
Aqua Ultraviolet 57 watt $73 includes bulb and O-rings
Aqua Ultraviolet 80 watt $190 includes 2 bulb and O-rings

Some of the more popular UV sterilizer's cost to replace the ballast or the Quartz sleeve.

Lifegard Aquatics Pro-MAX 55 watt 3" Ballast $138, Quartz sleeve $35
Lifegard Aquatics Pro-MAX 90 watt 3" Ballast $138, Quartz sleeve $38
Lifegard Aquatics Pro-MAX 120 watt 3"Ballast $138, Quartz sleeve $43

Pentair Aquatics 40 watt Ballast $110, Quartz sleeve $46
Pentair Aquatics 50 watt Ballast $110, Quartz sleeve $46
Pentair Aquatics 80 watt Ballast $133, Quartz sleeve $46

Aqua Ultraviolet 40 watt Ballast $107-$154, Quartz sleeve $84
Aqua Ultraviolet 57 watt Ballast $110, Quartz sleeve $51
Aqua Ultraviolet 80 watt Ballast $161, Quartz sleeve $168


I also want to note you may want to look into if the UV's power supplies have any known issues running through GFCI power outlets. I have read a lot of complaints lately that the Pentair's power supplies continually trip GFCI outlets every few hours. I would also take a few bad reviews as a grain of salt as more people tend to leave reviews when things aren’t working right rather than when everything is perfect.

Below is an old picture of a 360 watt UV that I use to run many moons ago. You will notice how you can actually see the UV light through the tubes because they have gotten so thin over the years of UV exposer. You will also see how repairs had to be made because the tubes got paper thin and they started leaking. This is one of the reasons why I like the replaceable sleeves on the Lifegard Pro-Max units.

I hope you Guys and Gals fine this little write up helpful in making a choice on the right UV for your application.

I personally got the Emperor Aquatics 80w for my system. I did a lot of research and went with Emperor due to their years in the industry and their footprint within the commercial and aquatics industries. Amazing workmanship and dependability in this thing. Love it!!

 

[Malcontent]

Except that has been proven not true Malcontect. They have shown that there are plenty of things you can kill on a slower flow through a sterilzer with x watts that you can not kill with the same exact sterilizer with 4x the flow. Example 8x flow at 30,000 will not give you the same killing power as 1x flow at 240,000 on the same sterilizer the faster does better on algae and weaker things while the high powered slower pass works on some diseases that the other won't. Multiple passes only are additive on killing power if they are plumbed back to back an inch or 2 apart. If you are flowing back into the tank and around again the extra passes from more flow are not additive in killing strength.
These 2 settings will have completly different outcomes on what they can kill and how much of it they kill:
Sample 120W UV
4,000 gph=30,000 uw/s/cm2
500 gph=240,000 uw/s/cm2

Proven? Where?

If marine ich is anything like FW ich, the free swimming stage is not the feeding stage therefore it has a finite amount of energy to repair UV damage.

Bacteria can feed and replicate between trips through the sterilizer yet faster flow rates control them better...

 

[Aardvark1134]

Read anything from any manufactuer or any peer reviewed article thanks.
If what you are saying was even remotely true they would not have flow rates...they would just have flow rate singular

 

[Malcontent]

Read anything from any manufactuer or any peer reviewed article thanks.
If what you are saying was even remotely true they would not have flow rates...they would just have flow rate singular

Is there any data from recirculating systems?

In a recirculating system, doubling flow rate, for example, halves the dosage but doubles turn over so the overall dose is the same.

Organisms obviously don't instantly heal themselves after a single non-lethal UV dose. I would expect bacteria to be more problematic since they can feed and reproduce rapidly while swimming stages of ich don't eat and whatever repair mechanisms they have draw from a finite pool of energy.

Read up on the reciprocity law of photobiology:

The reciprocity rule in photobiolgy - a review

If you think about it, it's intuitive. The danger is having too low a flow rate because it applies a dose greater than necessary to kill an organism in a single pass but as a result, less water passes through the sterilizer, and overall effectiveness is lower. Above a certain flow rate, there's no real difference--all flow rates above that perform equally.

And this is exactly the case:

Ultraviolet-C light inactivation of Escherichia coli and Salmonella typhimurium in coconut (Cocos nucifera L.) milk

Coconut milk was inoculated with Escherichia coli and Salmonella typhimurium to evaluate their inactivation using a double tube type UV-C light system…

www.sciencedirect.com

Journal of Food Protection | ScienceDirect.com by Elsevier

Read the latest articles of Journal of Food Protection at ScienceDirect.com, Elsevier’s leading platform of peer-reviewed scholarly literature

meridian.allenpress.com

 

[SixtyFeetUnder]

Question regarding appropriate flow for any experienced with Aqua UV units:
-I just purchased am aqua UV 57 for a 220g system. It recommends 1066 GPH flow.
-Comparatively the pentair 50 watt recommends: Algae & Bacteria Water Flow Rate - 1560GPH, Protozoa Bacteria Water Flow Rate - 260GPH.

I often see people suggest the lower numbers as decreasing those harmful bacteria for fish is the big goal. Anyone have experience here why one manufacturer gives different recommendations vs one flat recommendation for aqau UV? Any thoughts appreciated; this will be my first system running a UV.

 

[Jaebster]

Question regarding appropriate flow for any experienced with Aqua UV units:
-I just purchased am aqua UV 57 for a 220g system. It recommends 1066 GPH flow.
-Comparatively the pentair 50 watt recommends: Algae & Bacteria Water Flow Rate - 1560GPH, Protozoa Bacteria Water Flow Rate - 260GPH.

I often see people suggest the lower numbers as decreasing those harmful bacteria for fish is the big goal. Anyone have experience here why one manufacturer gives different recommendations vs one flat recommendation for aqau UV? Any thoughts appreciated; this will be my first system running a UV.

Your sterilizer is recommendeing GPH at 90,000 microwatts/cm2. The pentair is at 180,000 and 30,000 microwatts/cm2 respectively.

 

[Aardvark1134]

Because Aqua Uv mistakenly believes that running stronger than 90000 will cause reef issues when it doesn’t. Pentair like almost everyone knows 180000 works better for disease and doesn’t cause issues

 

[Badilac]

A little more about the heat a UV can add to the system. Below is a screen shot of my apex. Everyday my tanks temperature typically looks the same as 4/13/20 but that evening I took it off line as I just dosed some bottled bacteria and wanted to follow the instructions Fritz provided. Normal days with the UV the temp rises until it reaches 80F then my chiller kicks on until it drops back down to 77. Well you will see since I shut the UV and DC pump off the temp is now dropping on the tank.

 

[Aardvark1134]

You left out all the important details...how big the tank is, how big the uv is, glass vs acrylic, lid vs topless

 

[Badilac]

You left out all the important details...how big the tank is, how big the uv is, glass vs acrylic, lid vs topless

Some of that is posted in my original post.
300+ gallons, 90 watt, Acrylic, glass top over tank but topless sump, climate controlled room with t-stat set at 70.

Also it's dropped a little more since last screen shot.