UV Dosage Estimation

[BrettE2]

Hi all,

I started a thread earlier this week about ozone, and the topic of UV was also brought up. I wanted to get some thoughts on UV dosage, so I started this thread.

I have a total water volume of about 170 gallons. My primary goal is to make my water crystal clear. I also like the idea of having the option to try to kill things like Ich suspended in the water (should the need ever arise).

I was looking at the Aqua UV 57 Watt unit. I think the 40 Watt would be adequate, but it's massive, and would have to be mounted outside of my stand. The 57 Watt is (counterintuitively) much smaller, so it will fit nicely under the stand.

I'm planning to use a DC pump (Ecotech Vectra S2), so that I can easily adjust the flow rate.

@Visualsnow bought up dosage of UV, and I was hoping to pick is brain (and any others too) on this topic. How do I estimate what UV dosage I am providing? I don't see this in the specifications from the manufacturer.

I'm also not clean on the units. I've seen various including Energy per area as well as power per area. Those are similar, but of course not the same. What does one typically use?

It seems like flow rate, surface area of the tube, and perhaps the volume of the enclosure would come in to play. Give those quantities it would seem that you could estimate the time a quantity of water would be exposed to the UV, the energy from the UV, and the area over which that energy was spread.

Lastly I was planning to plumb it with the in and out in the sump. I realize that's not terribly efficient, since I'll be recycling some quantity of water. However, with the unit being somewhat oversized, I thought that might work out ok.

Thoughts?

Thanks!!
Brett

 

[BrettE2]

How do I estimate what UV dosage I am providing? I don't see this in the specifications from the manufacturer.

Ok apparently that's not entirely correct, perhaps I should have re-read the spec before posting...

From their sizing, it looks like I want a flow rate of appox 3x tank size for the 90,000 uW/cm^2 dosage. In my case that would be 170*3=510GPH.

I believe that you need on the order of 100,000 uW*s/cm^2 to kill Ich floating in the water, according to some study Hoffman in 1974. 90,000 is perhaps close enough to that for these esimates.

From their spec sheet the 57 Watt unit delivers 90,000 uW/cm^2 (I believe that should be uW*sec in the numerator?) at 1066 GPH.

1000 GPH is about what I expect to get out of a Vectra S2. Will it be ok to run it with that high of a dosage all the time?

Would it be ok to run the pump slower, so it's not at 100% all the time? That's going to give me an even higher dosage.

Thanks!!
Brett

 

[Visualsnow]

Ok apparently that's not entirely correct, perhaps I should have re-read the spec before posting...

From their sizing, it looks like I want a flow rate of appox 3x tank size for the 90,000 uW/cm^2 dosage. In my case that would be 170*3=510GPH.

I believe that you need on the order of 100,000 uW*s/cm^2 to kill Ich floating in the water, according to some study Hoffman in 1974. 90,000 is perhaps close enough to that for these esimates.

From their spec sheet the 57 Watt unit delivers 90,000 uW/cm^2 (I believe that should be uW*sec in the numerator?) at 1066 GPH.

1000 GPH is about what I expect to get out of a Vectra S2. Will it be ok to run it with that high of a dosage all the time?

Would it be ok to run the pump slower, so it's not at 100% all the time? That's going to give me an even higher dosage.

Thanks!!
Brett

I think this is plenty, if not more than plenty. Over the span of use, it will degrade in effectiveness without replacing some parts regularly anyway so I wouldn't worry too much about it because even if the UV can sterilize against ich, you have to ask yourself if it's actually cycling all the water or if it is cycling from the local area. Ich in low flow areas will never reach the UV if they make it to the rock beforehand, and that can be as simple as moving from fish in cave to cave wall.

I wouldn't over think it at this point, and I think if you install the UV and begin encountering a negative (if any negative ) impact on growth after two weeks, leave it off for two weeks, the. Try every other day instead of it's too much sterilization.

Throttling a pump is more work than I think it's worth imo because of the equipment degradation over time anywa if it's not replaced regularly which most people don't do. So, probably not worth your time because then you run the risk of beginning to kill things that you don't want to kill or damage due to their value inherent to the health of the reef.

If you need to quarantine :

This is my idea of decent QT, maybe over the top.

Remove all fish from tank.
House in separate 10 g tanks with consideration for their ability to be together and their size. Use those tanks to do the following:

14-day Copper Power or Chloroquine treatment with maybe 5-6 evenly spaced low dose formalin treatments

2 prazipro or fendendazole treatments 6 days apart in the same tank, so two weeks total time spent at this point

Transfer to a clean tank and feeding metro or fenbendazole laced food for another two weeks during observation tank period with acclimated black mollies to easily see parasites or problems if they develop, before reintroducing if no further problems appear.

4 week quarantine total, follow all bottle directions as they direct for each treatment.

If you have larger empty tanks I suppose that works too but I think 10g is more cost effective for multiple water changes and multiple rounds of treatment because you ultimately treat less water.

 

[BrettE2]

I wouldn't over think it at this point

Where's the sport in that?!

Throttling a pump is more work than I think it's worth imo because of the equipment degradation over time anywa if it's not replaced regularly which most people don't do.

Even with a DC pump?

If you need to quarantine :

I haven't with the current fish, but I plan to with the remaining fish.

Current fish:

• 2 Ocellaris clows
• 1 Firefish
• 1 Foxface
• 1 Royal Gramma
• 1 Midas Blenny

Furutre fish:

• 5-7 Lyretail Anthias
• 1 White tail tang
• 1 Yellow tang
• 1 Cleaner wrasse?

This is my idea of decent QT, maybe over the top.

Remove all fish from tank.
House in separate 10 g tanks with consideration for their ability to be together and their size. Use those tanks to do the following:

Seems reasonable compared to some I've seen.

14-day Copper Power or Chloroquine treatment with maybe 5-6 evenly spaced low dose formalin treatments

I thought you needed 30 days in copper to hit the whole lifecycle of Ich? Unless you did the so called tank transfer method?

If you have larger empty tanks I suppose that works too but I think 10g is more cost effective for multiple water changes and multiple rounds of treatment because you ultimately treat less water.

I have a 10, 20 long, and a 29 that available for QT. Planning on putting the Anthias in the 20 long, and the tangs in the 29. Plan to add Anthias to display first, then a few weeks later the tangs.

 

[Visualsnow]

1. You do you

2. Yes. I'm referring to the quartz glass and bulb replacements not the pump.

3.wrasse don't like chloroquine for some reason so I wouldn't dip them in that.


4.Tank transfer method, or black mollies.

 

[BrettE2]

2. Yes. I'm referring to the quartz glass and bulb replacements not the pump.

That makes way more sense. Thanks for all the help!!

 

[Visualsnow]

That makes way more sense. Thanks for all the help!!

Yep!

 

[SynDen]

I started doing UV on my tanks when I had a dino outbreak on one and nothing else helped with it. UV was the only thing that worked. So its most effective against things that release into the water column like that.

IME wattage doesnt really matter all that much, its contact time with the light that makes the difference. So you want to keep flow rate through the light fairly slow. High wattage will enable you to go a bit faster with the flow which helps in larger tanks so you can increase overall turnover, but just do which ever one works best for your setup.

As for the running time of the UV it is most effective during the night hours, when the lights are off, because that is when most organisms, that you would be targeting with UV, detach from the sand, or rocks, and become free floating in the water. Some will still be floating during the day, but much more is at night. So if you worried about doing too much UV, which frankly is very unlikely, then just run the UV at night