UV sterilizer GPH for parasites

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JustinMN18

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Hello,

I have a 100 gallon DT, 34 gallon sump.. about 100 gallons total water volume I think. I am running an AquaUltraviolet UV sterilizer, 15 watts. I know, low side.

Does anyone know what the GPH should be for parasites? Measuring with a gallon BRS jug, I was at 64gph, and I just raised it to 84gph. Thoughts?

Algae isn't a concern, I'm only focused on parasites. Thanks!
 
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Jay Hemdal

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Just my opinion, but a 15w UV, running on a side stream, isn't going to show real parasite control in a 100 gallon tank. Spotte reports that Cryptocaryon requires 100,000 uw sec cm2 compared to around 25,000 for most bacteria. He has a calculation to determine the dose but it is VERY complicated - you need to know the length of the bulb, the volume of water around it, plus the flow rate and wattage.

Jay
 
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Hello,

I have a 100 gallon DT, 34 gallon sump.. about 100 gallons total water volume I think. I am running an AquaUltraviolet UV sterilizer, 15 watts. I know, low side.

Does anyone know what the GPH should be for parasites? Measuring with a gallon BRS jug, I was at 64gph, and I just raised it to 84gph. Thoughts?

Algae isn't a concern, I'm only focused on parasites. Thanks!

The AquaUV Classic 15w is supposed to provide 90,000 uw/cm2 at 233 GPH and is recommended for a 75 gallon tank.
There is a chart in the instructions. I think you are correct on the size. The 25w is rated for a 150gallon tank.
if you can get more flow through it you should.
All UV dosages are calculated at the end of lamp life (14 months).
 
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JustinMN18

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Just my opinion, but a 15w UV, running on a side stream, isn't going to show real parasite control in a 100 gallon tank. Spotte reports that Cryptocaryon requires 100,000 uw sec cm2 compared to around 25,000 for most bacteria. He has a calculation to determine the dose but it is VERY complicated - you need to know the length of the bulb, the volume of water around it, plus the flow rate and wattage.

Jay
Thanks for that info. I have. No idea how to determine that. I found some calculation on some thread that I believe puts me at 62gph. Is that correct? I am considering getting a 25 watt unit.

Any thoughts about gph? I live next to BRS so I could pick up the sterilizer today if I go that route.
 

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Thanks for that info. I have. No idea how to determine that. I found some calculation on some thread that I believe puts me at 62gph. Is that correct? I am considering getting a 25 watt unit.

Any thoughts about gph? I live next to BRS so I could pick up the sterilizer today if I go that route.
Read the chart
Both are given. Dose and GPH needed.
https://aquaultraviolet.com/wp-content/uploads/2019/06/UV-Charts-Salt-and-Fresh-Water-Web.pdf

Can you divert the flow for the UV into a bucket. Then you time how long it takes to fill it to 2 gallons and calculate the flow in GPH. Say it takes 15 seconds to get 2 gallons.
2 gallons/15 seconds x 3600 seconds/ 1 hour = x gallons/ hour
2 gallons/15 seconds = 480 gallons an hour
 
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WVNed

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Is 90,000 the right number? I found this response.
Yes That is the number Jay was talking about to kill. Aqua UV uses 90,000 instead of 100,000
So your flow should be 400GPH or less to get a killing dose of 90,000 with a classic 25 watt.
But you want to get your flow as close to 400 as you can so the tank water goes through the UV the maximum number of times an hour.
 
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JustinMN18

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Yes That is the number Jay was talking about to kill. Aqua UV uses 90,000 instead of 100,000
So your flow should be 400GPH or less to get a killing dose of 90,000 with a classic 25 watt.
But you want to get your flow as close to 400 as you can so the tank water goes through the UV the maximum number of times an hour.
So based on that calculation / explanation in that picture, with a 15 watt bulb, I should be at 62, right?

Does the explanation of the equation make sense? It seems to me like there's a more ideal number (336,000 uWs/cm2) to get to, so you need to slow down the flow enough (by 3.73) to get the contact time.

So for a 15 watt, it's 233/3.73 and that's like 62. For a 25 watt it's 400/3.73, which is 107.

So basically if I upgrade to a 25 watt, I could cycle my tank 1x/hour at the parasite amounts. VS my current one is like 60% through every hour.

Does that logic make sense? I honestly have no idea. I'm basing this whole thing off of that picture I shared.
 

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Your logic seems correct.
I did a bit of reading. The 100,000 uWs/cm2 kills FRESHWATER ich.
Not marine ich
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).

So let's use the number you found in the middle. 336,000 uWs/cm2

Let's ask Jay. I don't know.
@Jay Hemdal
Is 1 time an hour turn over sufficient do you think at 336,000 uWs.cm2? I was thinking more like 2 or even better 3 at the minimum.
 
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You have to get the ich through the UV before it settles on a fish or somewhere to encyst. That takes flow.
If i could cycle it through my UV faster, I'd love to. But I just want to make sure I'm tuning it right for parasites, not algae. Algae isn't my concern at the moment haha.

If getting a 25 watt one means I can increase the water processing by 40% per hour, I think that's a good thing.

I just see everywhere people go between "very very slow" to "very very fast". So then I found that equation / explanation, and it seems like it's legit.... and goes towards the low side....
 
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JustinMN18

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Just my opinion, but a 15w UV, running on a side stream, isn't going to show real parasite control in a 100 gallon tank. Spotte reports that Cryptocaryon requires 100,000 uw sec cm2 compared to around 25,000 for most bacteria. He has a calculation to determine the dose but it is VERY complicated - you need to know the length of the bulb, the volume of water around it, plus the flow rate and wattage.

Jay
Hey Jay, any chance you could read my post from a few posts ago about the equation? I included a picture for reference..... Thanks a lot for your insight.
 
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JustinMN18

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Looks like you need the 25w or bigger. The things are expensive for a PVC tube with a light bulb in it.
No joke. What do you think I could sell my 15 watt aquaultraviolet one for? I've had it for about 7 months. I figure someone could find value in buying a used one to save some money. I should have just spent the extra 100 dollars when I bought this. lol
 

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No joke. What do you think I could sell my 15 watt aquaultraviolet one for? I've had it for about 7 months. I figure someone could find value in buying a used one to save some money. I should have just spent the extra 100 dollars when I bought this. lol
No idea. I am not a wheeler dealer. I tend to give things away LOL. Basically 7 months is half the life of the bulb. So mark it down 75% of what a new bulb costs and see if you get any takers. The rest of it doesn't wear.
 
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JustinMN18

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No idea. I am not a wheeler dealer. I tend to give things away LOL. Basically 7 months is half the life of the bulb. So mark it down 75% of what a new bulb costs and see if you get any takers. The rest of it doesn't wear.
Cool, thanks a lot for your help. I'm still hoping Jay chimes in with some insight just to verify that I'm not horribly wrong here haha. But you've helped me wrap my brain around this. Thanks a lot.
 

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Saying: AquaUV says you need 90,000 to kill protozoa (like ich), and Pentair says you need 180,000. I would trust the higher number. The number is controlled by the output of the bulb, and the flow rate.

AquaUV 15 watt = 90,000 at 233 gph. You can get 180,000 if you drop it to 116.5 gph theoretically. But is 116 gph enough turnover to be effective for 100 gallons? No, 3x to 5x turnover per hour is recommended to be effective. This 15 watt UV would be only good for a 23 to 38 gallon tank to get 180,000. To get the 336,000 number that's being mentioned, the 15 watt is way undersized.
 
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