Discussion of the weeK ~UV Myths~

[mojoreef]

Alrighty then in keeping with the Myths theme I thought we could tackle this one, this week. Now I dont think we need to get into a debate on weither or not to use UV but I think it would be great to hear why and why not. What will a UV kill that is bad for the reef? what will a UV not kill that is bad for a reef? What will a UV kill that is good for a reef? and what will a UV not kill that is good for a reef.

I think once we know what it will and will not do then it becomes an easy debate. So I hope the powers to be chime in on this one.

take care and have fun.


MIke

[Spanky]

AH HA

I poked around in the archives and found this thread.

[wildthings44]

This otta be good.... I don't use a uv, nor plan to (I am just not that good with these "high tech" things ) but I have always wondered what the deal was...

[Jimbo]

Thanks Spanky that was a long and informative thread. Ok a concern about UV that was not mentioned much in the thread is that it will oxidize organics and convert them to nitrate. This seems to be a bad thing in my opinion. There was also some interesting discussion about sponges making a niche in the system and feeding on some of the stuff the UV was supposed to kill. Last but not least, it seems some of the sand bed creatures and pods that live rock would produce free swimming larva.

Granted in our closed systems we have way more bacteria and organics floating around than in the ocean, but is it not possible to tackel this problem with things like added filter feeders in our tanks, a biological approach. Refugiums and DSB's are really not natural to fore reefs, but seem to be beneficial in processing organics and nitrates.

It was just a few years ago that people had bear bottoms on there tanks, big skimmers and lots of light, extra filter pads and UV/Ozone. Now many of us have the same but refugiums and DSB-Plenums. I can't say how much more successful my tank is with my current configuration. We are now seeing a trend to go backwards as far as I'm concerned, although have also seen people locating there sand beds out of the main system and increasing the flow, nothing wrong there

The increased flow increases the nitrogen processing ability of the LR and removes organics trapped in them so that the refugium and/or skimmer can remove them. So this brings up the question why do we need a sandbed at all, just go with a refugium / algea filter. For me I like the life that grows in the DSB, it is also back up denitrifier as long as you can keep it fairly clean and not a nutrient sink.

Anyway just my 2 cents

[SouthernReefer]

pordon me while i plagerize.....

ultra-violet light can damage dna. some microbes can repair this damage shortly after it occurs. but prolonged exposure causes irreparable damage by breaking the chromosmes.
uv-c is the highest engery of the 3 types of uv. it is capable of destroying nucleic acids of microbes with minimum contact and wattage. uv bulbs designed for water sterilization emit light at 253.7nm. the effectiveness of any uv. sterilizer depends on intensity, distance from bulb, length of contact time, and tempurature.

now that i have a basic understanding of ultraviolet, imo,that anything living that passes infront of any u.v. bulb is going to be dead or damaged severly, and will eventully die if it can't heal quick enough and it again passes thru the uv sterilizer. whether it be a copapod, phytoplanton, algea, or whatever, its in for a world of hurt.
so, it kills the good and the bad. killing the bad stuff is good, killing the good stuff is costly. you can always add phytoplanton, and a refugium or remote sandbed is a great place for copepods, amphipods, benifitial algea, micro-organisms and other stuff to continue to breed and grow and replace what has been wiped out by the u.v. sterilizer.
still looking for more data myself, but the book i have doesn't mention exactly what is killed, just general info stuff.

[Spanky]

>Ok a concern about UV that was not mentioned much in the thread is that it will oxidize organics and convert them to nitrate.<

Not exactly, most of your nitrate will be bound to things that aren't in the water column. The ones that aren't are the same ones that would be processed when the binding organism or flock deteriorates anyway. Running UV will reduce these available sinks from the get go.

>Last but not least, it seems some of the sand bed creatures and pods that live rock would produce free swimming larva.<

There's two big misconceptions about this. The biggest being the strength of UV required to fry these guys or even disrupt their ability to develop or reproduce. I can compare that to "UV doesn't work to kill Ick - UV will kill all your pods." It won't do one without doing the other. Luckily, most of these guys are substrate oriented as adults and are much more resistant to UV than other things (most all fish parasites). The other being the quantity and quality of the nutrition of the pods in these closed systems. One variety will tend to dominate.

>We are now seeing a trend to go backwards as far as I'm concerned,<

True, mainly because people are running into problems that weren't immediately evident and are looking for solutions. Realizing that most of these problems are a result of bad husbandry (not of a particular animal, but of a system) and they should have done things different from the get go.

>For me I like the life that grows in the DSB, it is also back up denitrifier as long as you can keep it fairly clean and not a nutrient sink.<

Me too! Depending on the type of sand you use, a shallow sand bed will also process nitrates just as well. It's the ability to process carbon that changes. Big rocks will too.

>so, it kills the good and the bad. killing the bad stuff is good, killing the good stuff is costly. <

They can be tweaked to avoid most of this.

[reefcam]

What about the use of UV to kill cynobacteria?

[Spanky]

Doesn't work well at all. Cyno tends to be localized in a high nutrient area and not up in the water column. Like cultivated bacteria.

[MtnDewMan]

What a timely topic Mike ... I wonder if I spurred it on at all with our emails

Thanks for getting it started.

[Cali Kid]

Great!

Now I'm on EBAY looking for a UV. I'm sure I'm going to get this look when I tell the wife:

[Spanky]

LOL

I know that look! it's the same one I get.........

[Cali Kid]

OK - let me see if I've got this straight.

You gotta break a few eggs to make an omlet.

[MtnDewMan]

Just installed my Aqua UV 15W sterilizer unit today. I have it mounted so that it recirculates water within my skimmer section. This is the chamber that sees the overflow water from the tank. It is upstream of my refugium so that my critters do not get sucked into it ...

Now time will tell to see how helpful or hurtful it may be