UV benefits?

[Toby_H]

I see more misleading "manufacturer recommendations" regarding UV lights than any other piece of aquarium equipment (heaters being the second most).
　
To eradicate parasites, kill algae, clarify water and all benefits in between, I have settled on a formula of:
1 W of UV strength per 10 gallons of aquarium volume (include sump where applicable)
10 gph of water flow through the UV per 1 W of UV strength (actual flow rate)
　
In other words, a 10W UV light on a 100 gallon tank with 100 gallons per hour flowing through it… adjust calculations to suit…
　
For reference, I’ve come up with this formula while raising/breeding Blue Dempseys which are well known to be prone to parasitic infection. This formula has allowed me to raise young Blue Dempseys with no symptoms of the internal parasites that commonly afflict this morph.
　
I am not aware of how you can have “to much UV” but after skimming through the links above it seems at some point it could break the ionic balance… although I do not know what level this would be. I can say with confidence I’ve run far more UV strength than I’ve recommended here on a system for many months with no noticeable ill effects.

 

[ccebr]

according to your calculations:-
tank = 110g = 10W
flow rate of all 3 filters = 383gph = 38.3W
what size UV should I get? 10W, 40W or somewhere in the middle (25W)

 

[Toby_H]

The flow rates I mentinoed are in regards to the amount of flow running through the UV light, not in the tank...

So for a 110 gal tank, I would ideally want an 11W UV. So I would choose a 10~15W UV, depending on brand. I've seen 10W, 12W, 13W & 15W... Danner/Pondmaster makes a 10W and I'm a fan of Danner's UV lights.

I would push 100gph through the 10W UV light (or 120gph through a 12W, etc)...

Keep in mind this is "actual" flow rates, not "rated" flow. Your average canister filter will have an "actual" flow rate of about 50% of what the motors maximum capacity is rated for. For example, the Fluval 205 is 'rated' at 180 gph... so we should expect it to actually push around 90 gph...

You can use a powerhead to push water through your UV light, but if you do be sure to thoroughly prefilter the water prior to pushing it through the UV light.

 

[ronnie08]

after reading this thread and the link's...iam sold on the UV!!

 

[Autophysn]

thanks guys! I have been pondering about this one. Seen them at the LFS, but you know how their are so many gimmicks out there. I bought my tank used and it came with a huge Algae problem. It has even penetrated under the silicone on the sides of the tank. I just recently added chemicles to try and control it, but this seems to be worth the investment.

 

[redbellyPirahna4]

would it have any benefits to a planted tank?

 

[ccebr]

Ok thanks for clearing that up nc_nutcase

 

[Toby_H]

Glad to help Ccebr...

A UV light will offer the same benefits to a planted tank as it would a non planted tank...
I do not know of any negative effects a UV light will have on plants...
Nitrates, phosphates, and other fertilizers are 'organic' but are not 'alive' therefore as far as I understand the UV should not alter them.

 

[kcinimod]

Those of you that have em, how often do you change the bulb?

 

[ccebr]

Those of you that have em, how often do you change the bulb?

I'd like to know that too. Can you use any UV bulb or do you have to buy the same one the unit comes with?