1 big or multiple smaller UVs for 400g?

[spwd]

Hi guys dont really know much about these but sounds like a good idea to have one on my new tank.
should i get one of these big ones or would i be better off with say 3 smaller ones for the same money?
The tank will be running somewhere around 7000 to8000 lph if that helps and will be 8.5ftx 32"x28" high

linkhttp://www.allpondsolutions.co.uk/72w-uv-sterilizer-1743-0.html


steve

 

[squint]

Well, assuming no ballast failures, bulb replacement is going to be the dominant cost in the long term. So perhaps you should go with whatever gets you the most total watts for the money.

 

[spwd]

Ballast failure,wth is that ?
I guess your right,the 72w one in the link is good for the money and only 2 bulbs compared to possibly 8 bulbs if i buy the smaller ones or at least 4 if they only have 1 bulb,the one in the link says its ok for sooo many 0000s of gallons so should be ok i guess.

Steve

 

[boldtogether]

Well, assuming no ballast failures, bulb replacement is going to be the dominant cost in the long term. So perhaps you should go with whatever gets you the most total watts for the money.

Agree. Multiples could get pricey quik!! You are supposed to change bulbs evry year...

 

[squint]

Many UV manufacturers exaggerate the acceptable flow rates even though they pretty much all use the same bulbs. I'd go by the Emperor Aquatics numbers since they seem to be more honest about it.

Another thing to consider is going up to a higher wattage than you think you need and changing the bulb less frequently. For example, a 57W bulb is only $10 more than a 25W bulb but you can bet it's going to be a lot longer before the 57W bulb's output degrades to below a certain threshold.

Most UVs have an electronic ballast. They sometimes fail. At least one manufacturer uses magnetic ballasts that are inexpensive but not as efficient.

 

[spwd]

So you can just buy a more powerful bulb then when the lower one gives up and how do you know its degraded too much,do you think the one in the link would be good for my new tank?

Steve

 

[squint]

Not really. The bulb wattage has to be matched to the ballast and the bulb length to the housing length.

The one in the link seems to be a generic UV and probably OK if you don't want to spend more. I'd try to search for others who have used that specific model or brand and find out what their experiences were. It uses 2 36W bulbs and I didn't see a quartz glass sleeve so I'd make sure it has a sleeve. UVs w/o sleeves are pretty rare these days though.

I'm sure there are ways to measure UV output but there are also charts of output vs. time so you can estimate how much longer you could use a more powerful bulb.

 

[Toby_H]

I am very confident in a formula of:

1W of UV strength per 10 US gal of tank/system volume...
10 gph of (actual, not rated) flow rate per 1W of UV strength...

Which comes out to a 40W UV light with 400 gph flowing through it on your 400 gal tank...


Danner (Pondmaster) makes a 40 W UV light. I've used a couple of their lights and I am very impressed with them. They are built like a tank. They are also submersible which may or may not be an added value.


The UV will begin to erode from the first moment it is turned on and will continue to erode every minute it is turned on. So your UV light will be most effective when you first install it and will become les effetive over time. With the above formula I suggested I am confident the UV will be able to kill parasites for up to one year.



As for the question in the title of this thread: 1 big or multiple smaller UVs for 400g?

One large unit will be cheaper to maintain and much more practical to plumb into your system. Multiple units will require multiple pumps/filters/powerheads placed in/on the tank. The only benefit that using multiple units will offer is a wider distribution of it's effects. But assuming your tank has ample water movement this will yield very little actual results.

Summary - I suggest one unit of 40+ Watts

 

[vamptrev]

I am very confident in a formula of:

1W of UV strength per 10 US gal of tank/system volume...
10 gph of (actual, not rated) flow rate per 1W of UV strength...

Which comes out to a 40W UV light with 400 gph flowing through it on your 400 gal tank...


Danner (Pondmaster) makes a 40 W UV light. I've used a couple of their lights and I am very impressed with them. They are built like a tank. They are also submersible which may or may not be an added value.


The UV will begin to erode from the first moment it is turned on and will continue to erode every minute it is turned on. So your UV light will be most effective when you first install it and will become les effetive over time. With the above formula I suggested I am confident the UV will be able to kill parasites for up to one year.



As for the question in the title of this thread: 1 big or multiple smaller UVs for 400g?

One large unit will be cheaper to maintain and much more practical to plumb into your system. Multiple units will require multiple pumps/filters/powerheads placed in/on the tank. The only benefit that using multiple units will offer is a wider distribution of it's effects. But assuming your tank has ample water movement this will yield very little actual results.

Summary - I suggest one unit of 40+ Watts

very well said!

i would also look into aqua ultraviolet. they have great quality with a wiper. i have one and im very pleased.

 

[spwd]

thanks guys but is that one in the link any good as its not expensive for a 72w,or il just get a 40w.

Stee