UV overdose

[ppurcell]

Is there an upper limit on the UV dosage that you can safely use on a system? I have a 40W UV, that I am considering connecting to my 120g system. It is rated for up to 300 gallons at a suggested rate of 300gph for protozoa.

Anyone see any potential downside other than being a bit larger than is necessary?

 

[kimha]

My situation is just the opposite. I have a 300g system with a 25W UV by Rainbow Lifeguard, which is a bit too small I think. I will trade you plus cash.

 

[NewSchool04]

Why the UV at all? Never used it, never understood why people do at all.

 

[kimha]

I use it to protect my existing fishes from parasites infection when introducing new fish. I turn it off after the new fish has been in the tank for 2 months.

 

[prugs]

No harm can be done with to large a UV unit. Most people but them too small & say they don't work It will help keep your tank warmer.

 

[vegadan1]

Don't they help control alge also.

 

[aaronpentz]

Yeah the kill anything in the water. Bad thing is they also kill any planktonic (Spelling?) food that all corals eat. They are good to have on hand if you have some sort of outbreak. I've got one but havent used it in probably 2 years.

 

[ostrow]

UV does not kill all planktonic life that passes through the unit, if you have the flow set correctly for your purpose. You have to be much slower even than parasite kill rate to kill plankton. If you adjust down when no reason to fite parasites, meaning, to control bacteria and algae, then plankton will survive.

Even those that might die offer nutrition to the reef.

Not all water passes through the uv on each pass.

Most people indeed undersize their uv units. 40W is in no way too large for your system!

 

[ppurcell]

I agree about the under sized rigs not providing much benefit. I see little to no benefit from my 18W UV. I plan to move that to my QT tank and hook up the 40 to the main system in short order.

Thanks for the input.

 

[aaronpentz]

<a href=showthread.php?s=&postid=8529957#post8529957 target=_blank>Originally posted</a> by ostrow
UV does not kill all planktonic life that passes through the unit, if you have the flow set correctly for your purpose. You have to be much slower even than parasite kill rate to kill plankton. If you adjust down when no reason to fite parasites, meaning, to control bacteria and algae, then plankton will survive.

Even those that might die offer nutrition to the reef.

Not all water passes through the uv on each pass.

Most people indeed undersize their uv units. 40W is in no way too large for your system!

Do you know the flow rates used to kill parasites and not the plankton for each given size of UV. I agree with you but the larger units require a faster flow to get the same outcome. Larger unit = larger kill rate with the same flow rate as a smaller unit.

 

[prugs]

<a href=showthread.php?s=&postid=8530538#post8530538 target=_blank>Originally posted</a> by aaronpentz
Do you know the flow rates used to kill parasites and not the plankton for each given size of UV. I agree with you but the larger units require a faster flow to get the same outcome. Larger unit = larger kill rate with the same flow rate as a smaller unit.

Each reputable manufacturer usually has that info available at their website.

 

[ostrow]

Correct, prugs. And it is possible to calculate. But in the end, first, there is a lot of skepticism about whether we are producing plankton in our reefs anyway. If we are, a fast flow will spare them, and it would take much slower flow to kill them than to kill parasites. Pods survive UV at parasite kill rates with no problem. I can attest to this, as I have pods in my display that only got added first to my fuge.