UV strategy - recommendations, flow rates, etc.

[alabella1]

I'm in between 2 options for my 155g tank.

I can either go one large - possibly 40 watt Aqua Ultraviolet Classic

OR

I can go with 2x 15w HOB advantage filters with 2 different speeds - one for algae and one for other stuff.

OR

I can do the 40 on my 155g DT and I can run the 2x HOBs on my 20g QT tank and my 30g Observation Tank.

Decisions, decisions.

 

[EeyoreIsMySpiritAnimal]

I'm in between 2 options for my 155g tank.

I can either go one large - possibly 40 watt Aqua Ultraviolet Classic

OR

I can go with 2x 15w HOB advantage filters with 2 different speeds - one for algae and one for other stuff.

I don't think it works that way... using 2 smaller ones at different speeds, that is.

 

[Waters]

Using two smaller ones will not work....they will not be able to keep up with the tank volume to make any difference (due to contact time with water and bulb wattage).

 

[alabella1]

bump

 

[EeyoreIsMySpiritAnimal]

@Waters , I guess he's gonna keep asking until he gets the answer he wants...? Lol

 

[DJF]

Bigger one at slower rate. If you can get the turnover needed for algae at the slower rate for parasites then you’re in a win win. Then again you’re talking to someone that had a bazooka size UV sterilizer for a 180 if you do 2 smaller ones at different speeds then there would be a calculation to get your total turnover… if that equals what you need for algae and the turnover of the slower one is high enough turnover by itself for parasites then you’re good. The whole point is usually slowing flow down for parasites wont get you the tank turnover you need for algae. The only benefit to running 2 is to be able to turn one off if you don’t need to address what it is dialed to address but in your scenario, you’d need both on always to get the turnover needed for algae. (My 2 cents)

 

[bushdoc]

This question about 2 UV sterilizers run at different pump speeds pops up here often. I think that when you run bigger UV at lower flow it kills all whatever UV suppose to kill. When you browse through scientific papers, not just manufacturer claims, it appears that most if not all UV sterilizers used in aquarium hobby are not good at eliminating parasites but only bacteria , algae, dinos.

 

[EeyoreIsMySpiritAnimal]

I can do the 40 on my 155g DT and I can run the 2x HOBs on my 20g QT tank and my 30g Observation Tank.

If you think you need UV on the 2 smaller tanks, this would be fine. Ultimately though, you'll need the properly sized one for the 155.

 

[EeyoreIsMySpiritAnimal]

This question about 2 UV sterilizers run at different pump speeds pops up here often. I think that when you run bigger UV at lower flow it kills all whatever UV suppose to kill. When you browse through scientific papers, not just manufacturer claims, it appears that most if not all UV sterilizers used in aquarium hobby are not good at eliminating parasites but only bacteria , algae, dinos.

The rationale I've seen for higher flow is that those organisms reproduce so quickly that you'll end up with a net reduction of 0 if you don't treat enough water in a short period of time.

 

[bushdoc]

The rationale I've seen for higher flow is that those organisms reproduce so quickly that you'll end up with a net reduction of 0 if you don't treat enough water in a short period of time.

Point taken, thanks, but that’s why it’s better to run more powerful UV sterilizer with “ relatively” lower flow recommended for this unit. This way you may achieve proper turnover and proper exposure time. If you run your unit at higher flow rate, you might not be able to damage those organisms sufficiently enough to stop them from reproducing.

 

[EeyoreIsMySpiritAnimal]

Point taken, thanks, but that’s why it’s better to run more powerful UV sterilizer with “ relatively” lower flow recommended for this unit. This way you may achieve proper turnover and proper exposure time. If you run your unit at higher flow rate, you might not be able to damage those organisms sufficiently enough to stop them from reproducing.

If enough water is not exposed to the UV, it doesn't matter how powerful it is.
That's why there are studies to show what flow rate and what amount of UV exposure are needed for different organisms.
There is no one-size-fits-all UV for hobby purposes. You need to decide what specifically you want to eliminate and adjust the system accordingly. While I'm not suggesting that any one manufacturer has the best instructions, almost all say to use different rates for different goals (e.g. parasites vs algae), and the strength of the UV is taken into account for tank volume recommendations.

 

[All_talk]

... If you can get the turnover needed for algae at the slower rate for parasites then you’re in a win win...

I have had this same thought, but this is the first thread on R2R were I have seen it mentioned. From some of the other responses it seems there are many that have considered this. I'm assuming implementing this is less common due to the cost and size of such a unit.