UV- Yes or No?

[Erik765]

I purchased a UV filter about 6 months ago from a not-so-reputable LFS that claimed it to cure my hair algae problem! I fell for it and shelled out the $200 for him to order me one. He said I would not be able to find the brand anywhere and that it's unique as far as algae control etc. The brand is pronounced Germicidle (not sure on the spelling). Anyway, as you can immagine, it didn't help with the algae (which I have since found other means to aid in this) but am wondering about what you would recommend as far as running it. I heard they kill good bacteria as well as the bad stuff. I notice my skimmer skims more when the UV is on, but is this just the good stuff getting skimmed? I've slowly been urking my way more towards natural filtration (refugium/macro/mangroves/dsb etc) and am not sure entirely how the UV would fit in to that. Do you use one? What are your thoughts on this?



E

 

[jdg]

I've heard that it helps to prevent parasites (Ich, Black Spot, etc) ... but this goes back and forth ... I don't even know that there's a right answer to your question. If you do a search for UV Filtration, you'll probably find a pro for every con.

Good Luck!

Joe

 

[pan_tsu?]

While the majority in these forums will say that you should NOT use one (and I don't necessarily say they are wrong), I am setting up a new tank and I am going to use one. I've seen several reef tanks online and show tanks at my LFS that use them 24/7 that have blown me away. I do understand the argument of destroying the good bacteria, etc....but I'm also not using a DSB, etc. And, as I've said, I've seen tanks where the corals are just going nuts and the water is crystal clear.

I hear a lot about how UV kills and is a complete detriment to tanks, yet I don't hear a lot of negative from the people that are using them. I always hear that things are running smoothly and corals are progressing nicely.

Check out the Dec. 2001 tank of the month on this site, it's one of the most beautiful tanks I've ever seen and he runs one....

 

[catweh00]

I use a 40 Watt UV sterilizer 24/7. Neve had a problem with any parasites, and I have a 4"DSB. Some people only turn theirs on when adding a new fish. My corals are doing great, but I really only keep softies.

 

[lawndoctor]

A UV sterilizer is one of the more difficult things to put on a reef tank if you want it to be effective. If you just read the directions, I doubt you will get what you want. A book cllaed "Aquatic Systems Engineering" by P.R. Escobal explains everything. I would read the section on UV sterilizers before installing one.

The key is to use a flow rate that is slow enough to zap the right bugs, yet fast enough to zap the whole tank volume frequently enough. The bigger the unit, the faster flow you can get away with. Most people use units that are too small and/or flow rates that are too high. Escobal's book has tables and graphs to help you figure out what is right for your tank.

I run a 25W Aquanetics UV sterilizer at 120GPH on my 75 gallon reef. It helped eliminate a dinoflagellate problem and has noticeably lowered the incidence of disease in the tank.

 

[64Ivy]

I run one. Heck, actually I run two! I consider them a potential safeguard for the fish...particularly since I don't quarantine. Scientifically, I'm not qualified to say whether they do any harm or good. But I can say is that my fish have never had 'ick' or any parasite problems since the tank has been up and that's about five years. Also, I'm one of the guys who's "corals are just going nuts and whos water is crystal clear" to quote pan_tsu so there doesn't seem to be any negative effects there either. The truth of the matter is that they are hold overs from my FO days and I use 'em because...well, I've ALWAYS used 'em. And I also admit to being rather susperstitious when it comes to reefing. So I guess what I'm saying is science or no science, if I had a 'filter' made from an old Barbie Dreamhouse filled with gym socks and everything was working well, I'm gonna stick with it.

I just wouldn't tell any of you guys.

 

[dreadhead]

64Ivy, just make sure the socks you're using in your filter aren't cotton. I heard that cotton socks often create nitrate problems, especially if they have yellow or red stripes.

Dread

 

[jdg]

The key is to use a flow rate that is slow enough to zap the right bugs, yet fast enough to zap the whole tank volume frequently enough. The bigger the unit, the faster flow you can get away with. Most people use units that are too small and/or flow rates that are too high. Escobal's book has tables and graphs to help you figure out what is right for your tank.

I run a 25W Aquanetics UV sterilizer at 120GPH on my 75 gallon reef. It helped eliminate a dinoflagellate problem and has noticeably lowered the incidence of disease in the tank.

I've heard the same thing on flow rate, and you have to be careful when contacting the manufacturer even. I was told that I could run an Aquanetics QIL15w on a 250g reef with a Rio800 and that would provide sufficient flow and turnover for my system. Though, if you look at posts from the other users, smaller systems are running 25w+ units.

The problem being that if you run the water too quickly through the UV, you won't kill the bugs, and if you run it too slowly through the UV, you won't turn the tank over quickly enuff and things will reproduce faster than the UV can keep up ...

Just a few thoughts ...

HTH,

Joe.

 

[lawndoctor]

In addition to UV wattage and flow rate, the diameter of the UV unit is a factor. Escobal says the most efficient diameter is 3". That is the diameter of the Aquanetics units, as well as many other brands. All of Escobal's analyses of UV sterilizer dosage are based on a 3" diameter unit. As an aside, Escobal is the president of Aquatronics, which makes Aquanetics. Personally, I don't think that fact detracts from the analyses in his book, but other people may think it does.

In the end, it really depends on what bugs you want to kill. For example, a protozoan requires a ten-fold higher dose (therefore a larger UV and/or slower flow) than a bacterium. This is a guesstimate, but at your tank size, UV wattage, UV unit diameter, and flow rate, I suspect your dosage is enough to kill some bacteria, but your turnover is not enough to kill all or most of them.

BTW according to Escobal you only need a quartz sleeve if the water is below 55F, like in a pond. Otherwise, all the quartz sleeve does is block some of the radiation (decreasing delivery does) and increase the operating temperature of the UV bulb (shortening its life). Aquanetics makes both quartz and non-quartz units, and the quartz units are more expensive.

 

[jdg]

Yah, I understand that the Quartz setup was basically for lower temperature environments; however, this unit was 'free' -- it came with a 90g system I purchased used. Basically, you're telling me the same thing I had figured ... the unit just isn't big enuff to kill the things I want to kill ... protozoan's, like Ich ... I want to kill Does anyone have the book and can recommend the size UV and flow rate I need? I'll buy a larger Aquanetics unit if I have to (3"). It's a 250g Reef System ... I also like to buy things a little larger than I need (ie: I might take this up to a 350g system at some point)

Thanks!

Joe.

 

[lawndoctor]

I actually just clocked mine with a gallon jug and a stopwatch at 48GPH. At that flow rate, my 25W unit kills most protozoa, and it turns my entire 90G tank+sump volume over more than twice daily. Once daily is considered minimum, twice is considered optimal.

For a 250 gallon tank, at one turnover per day, you would need a 60W unit at 100GPH to kill most protozoa. To get twice daily turnover, you would a second identical setup run separately, unless you could find a higher wattage UV sterilizer and increase the flow rate.

 

[Bomber]

>if I had a 'filter' made from an old Barbie Dreamhouse filled with gym socks and everything was working well, I'm gonna stick with it.<

At least get the Malibu Barbie, Mike. You can use the hot tub for a refugia.

There's five different germicidal bulbs that are appropriate for UV use. Two of them are HO (NO-normal output, HO-high output) german bulbs, the rest are all NO bulbs. You have to know what bulb you're using in order to "size" a UV. More than likely, if you're using a HO bulb you and your wallet will know it.

As far as flow rates and diameter of the unit, again depends on which bulb you're using. It's common for HO units to use a 5-6" diameter (the bulb is more powerful). Whether you need to use a quartz sleeve is also dependent on the bulb you're using and it's optimum operating temp. One large unit works better than two smaller ones (it's not the length of exposure but the intensity).

A formula that works for us is:

system volume X 4-5 turnovers per hour = UV sized to kill what you're trying to kill at that flow rate.

200gal system X 5 = a 1000 gallon per hour flow rate.(sized for Normal Output bulb)

>Does anyone have the book and can recommend the size UV and flow rate I need?<

100 X 5 = UV rated to kill parasites at a flow rate of 500gph.

We use Emperor Aquatics HO units exclusively.

HTH
Jerel

 

[lawndoctor]

Jerel:

I'm glad we have an expert here, because all I'm really doing is quoting someone else's book. I have some follow-up questions:

First, I'm confused about the wattage in your example. If you're saying that in a 200 gallon system you would run 1000GPH through an Emperor sterilizer, what wattage unit would you use to ensure killing the bugs that cause most of the mischief in home aquaria?

Second, I'm confused about the effects of using HO instead of NO. Aren't they just different size lamps putting out the same wattage? So woouldn't a 25W HO unit and a 25W NO unit kill the same bugs if used at the same flow rate?

Finally, it seems to me that different diameters and brands of UV sterilizers are like apples and oranges. How do you compare them directly and reliably? Based on each unit's delivery dosage as a function of flow rate?

Thanks - Chris

 

[Bomber]

Hi Chris :wavehand:

First, I'm confused about the wattage in your example. If you're saying that in a 200 gallon system you would run 1000GPH through an Emperor sterilizer, what wattage unit would you use to ensure killing the bugs that cause most of the mischief in home aquaria?

Not just Emperor, but any Normal Output (NO) unit. It's going to depend on the make of bulb and type of bulb. You can use a lower wattage bulb if it's HO. HO is about half way between a NO and VHO.

I would use a 80 watt HO bulb on a 200 gal system.

Second, I'm confused about the effects of using HO instead of NO. Aren't they just different size lamps putting out the same wattage? So woouldn't a 25W HO unit and a 25W NO unit kill the same bugs if used at the same flow rate?

NO is the type of light bulb that comes with your off the shelf light hood for tanks. VHO is what you immediately upgrade to. HO is in between.

Finally, it seems to me that different diameters and brands of UV sterilizers are like apples and oranges. How do you compare them directly and reliably? Based on each unit's delivery dosage as a function of flow rate?

You really can't. Unless you do a lot of research and phone calls. Best bet is to stick with a reputable company that also services the commercial industry - not hobby. Even then you need to nail them down to exact numbers, talk to a technician never just the salesman, and talk to the owner if you have to.

HTH
Jerel

 

[andrejka]

Jerel:

Would a unit with a 9W PC be comparable with a 25W NO then?
Will it be enough for 50G of system water?
The manufacturer recommends it for up to 200G tanks with recommended flow of 200gph:
Double Helix UV Sterilizer
I'm absolutely lost in all the variety... Please, help

 

[jdg]

I actually just clocked mine with a gallon jug and a stopwatch at 48GPH. At that flow rate, my 25W unit kills most protozoa, and it turns my entire 90G tank+sump volume over more than twice daily. Once daily is considered minimum, twice is considered optimal.

For a 250 gallon tank, at one turnover per day, you would need a 60W unit at 100GPH to kill most protozoa. To get twice daily turnover, you would a second identical setup run separately, unless you could find a higher wattage UV sterilizer and increase the flow rate.

Wow ... we're talking $400 + for an Aquanetics 60W unit ... ouch ... but ... according to their chart, I can kill typical protozoans with a max flow rate of 11gpm (660gph), so uhm, I can turn my tank over like 2.5 times per hour ... not even day ... Something doesn't add up right here ... ?

 

[Bomber]

Andrey,

I can see why! I'm not familiar with PC UV's but I can tell you what I've heard. I was told that the bulbs degrade faster and for some reason don't have as much umph (power) as a regular florescent type.
Probably the biggest problem with UV's is the manufacturers themselves. They rate them as "clarifiers", primarily to be used on fresh water tanks and fish ponds. The amount of UV to kill free floating bacteria and algae is considerably less than what it takes to kill protozoan and parasites and the method is different. You'll actually get a better kill with algae by having a longer exposure. The opposite is true of parasites.
Think of that this way. You can use a lower wattage bulb with either a slower flow rate, or a faster flow but multiple passes through the UV and be effective against a algae/bacteria bloom. In order to kill parasites, you need a much higher wattage and proportionately slower flow rate, that exposes the parasite to a stronger dose at one time. (I hope you followed that, I didn't)
The unit you linked to is obviously sized to kill algae and some bacteria. They mention having a longer exposure.

Really all I can tell you is what I would do. For a 50gal system that I wanted to kill Ick or other parasites, I would use a 40watt UV. Here's the reasons why.
A 25w NO is probably rated about 150gph flow at max effective for parasites, with a constant run flow of probably about 250gph. Considering that NO bulbs degrade about 40% within the first 6-8 months (that can depend on the ballast too), within 6-8 months you're down to a effective flow rate of +/- 80gph. AND you have to buy a new bulb.
If you start out with a 40w UV, you're in your proper flow rates even when the bulb degrades 40%, AND you don't have to buy a new bulb. In other words, the unit will go a lot longer without you having to buy new bulbs. How much longer, again will depend on the bulb you're using. Most of our units are sized to go two years on one bulb.

Another big problem is the manfs again. Some rate their units right out of the box. Very few, but there are some, that rate their units at the units effectiveness at the end of one year (after the bulb degrades). That makes it ever harder to compare brand X UV and brand Y UV. Again look at the commercial units, if those guys mess up - they have to deal with us and it's not pretty.

did that help?
Jerel

 

[jdg]

Do you have a link to a recommended manufacturer? Can I buy one from you? lol

Joe

 

[lawndoctor]

Jerel: Thanks very much for all the info. In case anyone's interested, the cheapest price I saw was at Sea Quest Marine. Emperor 80W HO for $735 and replacement bulbs for $90. Emperor's web site says the bulbs are good for a little over a year.

jdg: In addition to what Jerel said about the manufacturer ratings, note that "turnover time" is different than GPH. For example, at 200 GPH a 200 gallon tank will not get a complete exchange of its volume in one hour. Rather, the turnover time for a 200 gallon tank at 200GPH is 9 hours.

 

[jdg]

hum ... on the turnover rate ... how does that work out? Is there a formula for this? It looks like I may be okay with the Aquanetics 60il then ... based on a 9x (?) example, I can turn over my 250g in 3.5-4 hours with a 660gph unit ... no?