Will my UV kill my phytoplankton?

[runway1]

I run a UV for about 3 hours/day. Will this kill the DT plankton I'm feeding? Thanks!

 

[fishfreek]

We need to know more info about the UV. Whats the UV wattage, whats the flow rate thru the UV and how old is the bulb. Have you ever cleaned the inside of the UV unit?

The quick and simple answer is yes it could kill live phytoplankton IF the exposure time is long enough. The flow rate and wattage of the bulb will govern if the exposure intensity and time is long enough to do damage to the phytoplankton.

 

[JPloman]

More than likely it is killing them. Just as fishfreek said, it depends on the wattage, flow rate and the age of the lights.

We had a very slow flow rate and high wattage in ours... needless to say we had NO pods in our main tank until we took it off.

 

[Toirtis]

If your flow rate is correct, it will kill anything (or at least 99.99%) that passes through it....otherwise, it is not doing its job properly.

 

[IfoundNemo]

Here is an article about UV sterilizer
http://aquariumadvice.com/showquestion.php?faq=2&fldAuto=31

 

[runway1]

I use a turbo-twist 8 watt. It's just after the return pump, which is Rio 1400. With about a 4 foot head, the chart says it pumps about 243 gph.

So, seems I'm killing at least some of the critters. What if I turned off the UV on feeding days and back on days when not feeding plankton? Does this make sense or is the plankton a constant population?

 

[JPloman]

Well you are really talking about pods. The plankton you feed is more than likely already dead. Pods will grow in your tank all the time and it is best to have them in high quantities.

Here is how to figure out if you need it on or not. Are you currently fighting a bacteria or problem algae? If your answer is yes, keep it on and just turn it off every once in a while. If the answer is no, turn it off until you have another problem. It is really not good to keep a UV sterilizer on all the time anyway. It not only kills bad stuff in your tank, but it also kills the good stuff. :?

Another think to think about is... what type of fish do you keep now and what kind do you desire in the future? If you are looking to raise fish that live off pods, such as seehorses or mandrins, it is important to go ahead and keep that UV sterilizer off for good. For those types of fish you want a very, very high pod population and every thing you do to the tank now is going to effect when you can put those fish in your tank.

 

[runway1]

Thanks JPloman. A dark redish spot recently appeared on my sand bottom (cyano??). I would like to grow pods just as a sign of a healthy tank but I don't REQUIRE them for mandrins, etc.

My UV schedule was parallel to my fluorescent schedule - 1.5 hours morning, 1.5 hours at night. Recently, I turned it off to feed DT phytoplankton (which is supposed to be live).

So, should feed DT and turn it off that day? should I feed DT and run UV for only 1-2 days/week? Should I keep it off until I need UV?? Hummmmmmmmmm

 

[fishfreek]

Running the UV for that short of period honestly is probably having very litle effect on the tank. The overall % of water thats acutally filtered by the UV is goig to be very low. One of our articles has a math equastion to help calculate how long you need to run a UV to get a specific % of filtered water.

DT Phyto will be alive IF its handeled properly and used in fairly short order. The longer it sits in your frige the more of the phyto that dies.

 

[JPloman]

Cyano will not be helped by a UV filter to be honest with you. The only thing that will help that is to reduce feedings, get a skimmer and harvest the scum.

I like the advice that fishfreek is giving you on the usage. He lways give the best advice!