Uv sterilizer, should I get?

I took my line directly out of the conclulsion at the bottom. I'm still sifting through all the detailed information that lead to the conclusions. The lines you provided are from the hypothesis prior to testing.

From the conclusion:
"Aquaria subjected to active filtration via skimming present water column bacteria populations that are approximately 1/10 of those observed on natural reefs. The consequences of this disparity on the long-term health of the tank's livestock are not known. How do reef tank organisms adapt to such a bacteria-deficient environment? Is the whole food web in an aquarium perturbed, or are there compensatory mechanisms that maintain an appropriate energy transduction through all of the trophic levels? Is "old tank syndrome" related to possible nutritional deficiencies stemming from this bacteria "gap"? Alternatively, could "old tank syndrome" be symptomatic of a gradual decrease of bacterial diversity as a consequence of selective skimmer-based removal of only bubble-susceptible bacteria? At present, it is not possible to go beyond speculation on these points - further research is needed."



It really is strange how well our tanks do considering the bacterial deficit (well, deficit specifically in the water column.)

 

I'm not sure our tanks do well. It's fairly well understood that growth rates in captivity pale in comparison to in the ocean. That said, in the ocean, nutrients are non-existent and corals don't get the nutrients they need from zooxanthellae (they get sugar for energy, other things such as nitrate and phosphate are not delivered in sufficient quantities). In captivity however, while food is low, nutrients are very high compared to in the ocean (likely even in many "ULN" systems). So, corals may be getting some nutrients from dissolved nutrients in the water, which makes up for lack of food. I suspect, for example, that's one reason people have issues when running BP or other carbon dosing mehtods; because now there is little food and less dissolved nutrients.

Going back to UV though, from the article " it is probably safe to conclude that the UV sterilizer does not have a significant effect on the bacteria population levels in the tank's water column."

That's the problems with UV. UV has been studied a lot for aquaculture, and usually the conclusion is that is isn't worth it. You need a really big unit, with a high flow rate to do anything. And I agree with AZ, if you do do anything, likely you'll be doing as much bad as good. There just aren't many bad things floating in the water. Most are surface dwelling, but even if they have a free floating phase, you need to pass all of the water through it fast, to kill it before it reproduces. Most units sold for the hobby aren't nearly big enough to do so. So, I think there may be occasional uses, but overall, I think they use a lot of electricity, require a lot of maintenance and do little, besides perhaps make people feel good. Just my .02 though...

 

Here is the cut and paste ot the conclusions of the article:

4. Conclusions
The preliminary studies described herein document, for the first time, the modulation of water column bacteria population in reef tank water as a consequence of either (a) carbon source addition or (b) mechanical filtration (GAC, skimming). This information bears on the Carbon Dosing hypothesis for nutrient removal in marine aquaria.

Aquaria subjected to active filtration via skimming present water column bacteria populations that are approximately 1/10 of those observed on natural reefs. The consequences of this disparity on the long-term health of the tank's livestock are not known. How do reef tank organisms adapt to such a bacteria-deficient environment? Is the whole food web in an aquarium perturbed, or are there compensatory mechanisms that maintain an appropriate energy transduction through all of the trophic levels? Is "old tank syndrome" related to possible nutritional deficiencies stemming from this bacteria "gap"? Alternatively, could "old tank syndrome" be symptomatic of a gradual decrease of bacterial diversity as a consequence of selective skimmer-based removal of only bubble-susceptible bacteria? At present, it is not possible to go beyond speculation on these points - further research is needed.

On the other hand, our studies have shown that bacterial growth appears to be carbon limited in reef aquarium water. However, there is a demonstrable difference between reef tank water in an active reef tank, and reef tank water removed from the tank. In the latter case, bacteria consumers are largely absent, and so fueling bacteria growth via carbon addition translates to rapid and large increases in bacteria population. In an active reef tank, however, this population increase is not manifest, presumably because active predation keeps the overall level in check. Thus, the highly dynamic nature of bacteria populations in the water column of reef aquaria is highlighted by these studies. From a different perspective, the bacteria population in a reef tank seems to act as a buffer to help dissipate the otherwise potentially serious negative consequences of (inadvertent?) tank pollution via rapid carbon addition, at least perhaps up to a saturation point.

Finally, mechanical filtration in the form of skimming but not GAC does provide an effective means of bacteria export, at least up to a point. It appears likely that some types of bacteria are indeed "skimmable", but others are not. Thus, skimming inadvertently provides severe (?) evolutionary pressure to skew the tank's resident water column bacteria population to favor the "non-skimmable" cohort.

The bottom line with respect to the carbon dosing hypothesis is clear; the basic tenets of this theory appear to hold up to experimental scrutiny; carbon dosing does increase water column bacteria populations, and skimming does remove some bacteria with their attendant nutrient loads. Thus, the underlying science behind this approach to nutrient export appears valid.


Todd wrote:

Having obtained a Masters Degree myself, I have been trained in experiment design, theory behind valid research, etc. I think the authors would agree that there were some good points made overall, that any premise based on one or two tanks water, well, just won't hold water. While it might be true for many, if not all ofher tanks and their variables, we don't know.

One of the Pro's of an ATS (I don't run one, not yet anyway), is that it preserves the tank flora better than a PS.

The article did say that a non spiraled UV filter did not affect the Bac. load. Not many poeple run a non spiraled UV filter these days, do they?

A good article however, good reading, entertainment maybe? As the article pointed out, the daily bac. load of the DT's tested (probably all DT) varies alot. While it probably is accurate that most active reef water has an overall higher Bac load than my DT.
I'm glad it does! Our/my DT has no where near the active filtration and nutrient export capabilities as a natural reef does!

Peace out

 

Does a Spiraled UV really make that much of a difference on the efficiency?

 

Spend your money on better lights and a bigger skimmer. I think you will be happier. I didnt read all of the other responses but I believe the jury is still out on the UV sterilizers.

 

Apparently so. I think they call it 'dwell' time. If you think about it, a section of water passing thru the UV cannister, spends much more time in the UV light when it spirals around the bulb, vs. going straight by.

 

+1 lol

 

Todd, I agree with you about needing repeatability and reproducibility. As mentioned though there are repeated and reproduced studies in the scientific literature. Intensities, dwell times and kill rates, for a number of organisms have been studied. You seem to be criticizing what, for hobby literature is a pretty good study and preferring to go with what? Anecdotal claims and claims from UV manufactures maybe? That's fine, it is a preliminary study. However it does build on what is already understood in the scientific community. So, if you have scientific training go read the literature LOL.