Properly sizing UV Sterilizers

oz · Dec 23, 2009

mojo;440981 wrote: ....I don't think I'd ever consider running a UV from a return pump,......

Unless the return pump is strong enough to "T" off the return line with a gate valve to feed the UV.

As you know, I T off a Hammerhead to feed the UV then the output feeds the skimmer since they need roughly the same GPH. This seems to accomplish 2 things. Any dead material is likely to be skimmed out and the heated UV water is "cooled" a little with the introduction of air to the skimmer before it returns to the sump.

ichthyoid · Dec 23, 2009

grouper therapy;475477 wrote: +1 if I slow the water through my 57 watt down half of it's recommended flow rate then am I accomplishing the same as a n 114 watt uv and just processing less water per hour? I would think the a single higher wattage uv(400 watt viper) would penetrate the cells better than prolonged exposure would. Any thoughts?

ichthyoid · Dec 23, 2009

Also-

Use of ultraviolet (UV) sterilization to kill
theronts has been suggested, based on research
involving Ichthyophthirius multifiliis (freshwater
"ich"). The recommended UV dose for
Ichthyophthirius theronts is 100,000 μWsec/cm2
(Hoffman 1974). However, UV doses required for
Cryptocaryon irritans are anecdotal or extrapolated,
and range from 280,000 μWsec/cm2 (industry
numbers) to 800,000 μWsec/cm2 (Colorni and
Burgess 1997).

http://edis.ifas.ufl.edu/pdffiles/FA/FA16400.pdf">http://edis.ifas.ufl.edu/pdffiles/FA/FA16400.pdf</a>

(that would be from the University of Florida-Extension Service, the second best school in that great state!)

grouper therapy · Dec 23, 2009

Combination of both! Thanks Ich saved that link.

ichthyoid · Dec 23, 2009

grouper therapy;475741 wrote: Combination of both! Thanks Ich saved that link.

Grouper- as always, you are very welcomed sir.

Also, some more food for thought-

"Other biological molecules with unsaturated bonds may also be susceptible to destruction by UV – examples include coenzymes, hormones and electron carriers. The ability of UV to affect molecules other than DNA and RNA is particularly interesting in the case of larger microorganisms such as fungi, protozoa and algae. In these microorganisms, although UV may be unable to penetrate as far as the DNA, it could still have a lethal effect by damaging other molecules."

http://halmapr.com/news/aquionics/a-comparison-of-microbial-repair-mechanisms-with-low-pressure-and-medium-pressure-uv-lamps/">http://halmapr.com/news/aquionics/a-comparison-of-microbial-repair-mechanisms-with-low-pressure-and-medium-pressure-uv-lamps/</a>

It is interesting to note that in some instances, the damage caused by UV can be repaired through what is known as 'photoreactivation'.

Also, medium prressure lamps tend to be more effective, in general, than the more commoon low pressure lamp.

-FWIW

mojo · Dec 23, 2009

LilRobb;475451 wrote: I actually have a problem with this statement.
While it was explained earlier that it is all about the POWER of the unit and how deep the UV radiation penetrates the cell - how does this compare to hooking up two 120W ones in-line?
it doesn't fortify the raditation, just prolongs dwell time...

They don't make 120w UV bulbs - 57w is about as large as they readily make.

Effective killing power is a combination of both the radiation and and the dwell time. A 5w sterilizer is just as effective as a 400w sterilizer if the flow rate were low enough (although the effectiveness on a larger system will be much lower).

Again, think about a sunburn- you could either be out in full sun for 3 hours or "half sun" for 6 hours and still burn the same amount.

grouper therapy;475477 wrote: +1 if I slow the water through my 57 watt down half of it's recommended flow rate then am I accomplishing the same as a n 114 watt uv and just processing less water per hour? I would think the a single higher wattage uv(400 watt viper) would penetrate the cells better than prolonged exposure would. Any thoughts?

Not according to the research. The research shows us that a certain amount of radiation over time is effective in killing parasites and bacteria. You can't kill anything more after it's already dead (although more radiation won't hurt).

To put it in another context, if you exposed me to enough nuclear radiation to kill me, increasing that radiation amount (the same as adding a 400w bulb) isn't going to kill me any more. However.... you could expose me to that higher radiation for less time and it'd be just as effective.

And both of these points goes back to the original point of this thread- effectiveness is optimal at certain radiation x duration.

grouper therapy · Dec 23, 2009

mojo;475790 wrote: They don't make 120w UV bulbs - 57w is about as large as they readily make.

Effective killing power is a combination of both the radiation and and the dwell time. A 5w sterilizer is just as effective as a 400w sterilizer if the flow rate were low enough (although the effectiveness on a larger system will be much lower).

Again, think about a sunburn- you could either be out in full sun for 3 hours or "half sun" for 6 hours and still burn the same amount.

Not according to the research. The research shows us that a certain amount of radiation over time is effective in killing parasites and bacteria. You can't kill anything more after it's already dead (although more radiation won't hurt).

To put it in another context, if you exposed me to enough nuclear radiation to kill me, increasing that radiation amount (the same as adding a 400w bulb) isn't going to kill me any more. However.... you could expose me to that higher radiation for less time and it'd be just as effective.

And both of these points goes back to the original point of this thread- effectiveness is optimal at certain radiation x duration.

Thanks Chris . I see the point makes sense to me now.

lilrobb · Dec 23, 2009

I thought I remembered a post earlier where someone said that bulbs under x watt are useless, not emitting enough radiation to reach the nucleus.
My bad.

If we could get statistical data how fast ich can reproduce at temperature x and we could also figure out how many ich cells are being killed per hour by y radiation we could then much better size the needed unit to fight it properly.

mojo · Dec 23, 2009

LilRobb;475841 wrote: I thought I remembered a post earlier where someone said that bulbs under x watt are useless, not emitting enough radiation to reach the nucleus.
My bad.

No, but there was a discussion about effectiveness of using a lower radiation x time. My contention is that there's the data for controlling Ich only exists for levels to kill Ich, so therefore those numbers should be followed.

Whether you do that with a 5w or 5000w UV is irrelevant, as long as the flow matches to give the correct dosage.

If we could get statistical data how fast ich can reproduce at temperature x and we could also figure out how many ich cells are being killed per hour by y radiation we could then much better size the needed unit to fight it properly.

I agree 100%. Just as a 25w UV won't sterilize the Atlantic ocean, a 400w would be overkill for a nano. Data is needed to determine what the optimal range is in the middle.

elfloyd · Dec 23, 2009

Hey Chris... I book marked this thread for when I need it... which is now! Great thread by the way and it deserves to be resurrected.

Make sure my numbers are correct.

- 180 g system
- 50 g sump
- total water volume ~230 g

UV - Gamma 40 w (Gamma website states rated at 200g)
Rated at 30,000 uWs/cm2 @ 2880 gph

So, to get to 336,000 uWs/cm2 I need a flow rate of 260 gph

Does this sound correct? It also matches your rule of thumb of 1x tank size turn over.

mojo · Dec 23, 2009

Yup- that looks correct to me!

elfloyd · Dec 23, 2009

Alright! Thanks!

skriz · Dec 23, 2009

ReefDog;515666 wrote: Quick question- In today's reef setups, are UV Sterilizers something that should be considered standard equipment? Or are they only used when problems crop up, as a means to fix something that has gone wrong (such as disease or algae blooms)?
Hoping I could get some informed opinions on the subject, as I presently do not use a UV Sterilizer.

UV's should be implemented from the start. Prevention is way better and easier than fixing something after a problem has already presented itself.

I've worked on systems up to 190,000 gallons and at a glance you can tell which ones use UV and which ones don't.

rbredding · Dec 23, 2009

probably one that costs about $2/gallon...

skriz · Dec 23, 2009

Assault;516420 wrote: my build totals out at about 1,000 gals which UV would effectively work for me? I don't really care about having the best, just the ability to kill ich and harmful algae, in other words, the biggest bang for my buck.

Emperor 320 watts; that's what I have.

skriz · Dec 23, 2009

Assault;516660 wrote: Raj, if I buy everything you have ,my daughter won't be going to college

Who needs college when you have a UV like that? :lol2:

rbredding · Dec 23, 2009

his ls like $5/gallon...

elfloyd · Dec 23, 2009

I have a 9w I'll sell you... that's like $0.05 per gallon!!!

mojo · Dec 23, 2009

Akopley;570829 wrote: Do people use UV's just for clarity? That would be my main interest.

In larger tanks, the buildup of DOC's makes the water yellowish. I can certainly see that when looking end-to-end of my 7' long tank. Ozone takes care of that for me, but I'm not sure about the efficacy of UV on clarity (since I had ozone before UV). Some will say "yes" and some will say "no" - I'm not sure. But I can say that if you're looking for clarity, ozone will definitely give it to you.

UV, however, will give you sterilization that ozone likely won't be able to achieve.

jmaneyapanda · Dec 23, 2009

Akopley;570829 wrote: Do people use UV's just for clarity? That would be my main interest.

Only if you have free floating green algae in the water column. The water will look like pea soup. I doubt you have that. Most people use UVs in ponds for this purpose. However, in marine aquariums, they are most useful for pathogen control, when properly sized, as this thread elucidates. But it wont solve flocculation of particulates, or remove dissolved "yellowing" organics.

Another interesting this is that UV will break the bonds of many chemical components (which is why you are instructed to turn them off when using meds). For our aquarists purposes, it will dechlorinate, and will also break an ozone bond. So, if set up properly, and ozone treated water is run through a UV, carbon filtration isnt necessary.

Properly sizing UV Sterilizers

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