View Full Version : UV Question

03-13-2005, 11:15 PM

how long does it normally take for a UV to clear a pond?

I have a Zapp Pure 20 which I installed yesterday.

My pond is 12,000 gallons and the UV is after my bead filter.

The UV is rated for 20,000 gallon ponds at 6,000 gph.

My pump is pumping at ~ 4,500 gph.


03-13-2005, 11:47 PM
you should see improvement within 24 hrs. and cleared within 2-3 days

03-14-2005, 07:45 AM
Depends on how green the water is, i would say about a week if very green like pea soup.

03-15-2005, 02:03 AM
It will start clearing in hours--but can take up to two weeks to get as clear as it is going to get.

03-16-2005, 01:22 PM
I wondering about the turn over rate being a problem. Ideally you want to water to go through a UV within 2-3 hours as some algae can grow fast. With the pond at 12,000 gallons and the pump at 4500gph, it is taking around 2.6 hours to turn the pond over. Gary's rating on the unit indicates it can keep with with a 3.3 hour turnover. It could be that the UV lamp is powerful enough, but the turnover rate means it will take time for the UV to catch up with the algae growth.

03-16-2005, 05:45 PM
From what we've had here... it takes several days to get totally clear. I know its hard WAITING... but be patient. UV's are WONDERFUL :yes:

01-30-2006, 01:46 PM
Again, a UV can zap all the algae coming through the chamber...no problem. But if you are only sending the water through around ever 2.6 hours, that is a very slow turnover rate for the regular filter or for UV. You want water turned over as close to 1 hour as possible. I will be very surprised if any UV will work for you in high summer with such a long turnover rate.

UVing in a larger pond like yours may mean smaller UVs on each of the BD/filter circuits and on the skimmer/waterfall circuit.

02-21-2006, 12:02 PM
well, since so much algae is dying as we speak it would'nt hurt to backwash the filters on occasion. algae is a real clogger for filters, but when the uv gets it under control and all that matter is removed, it will be so much easier on the filter. after the algae is gone everything should be ok.

:yes: I would try to get the flow rate up a bit. :yes:

:yes: That could be your reason for the algae not clearing. :yes:

02-21-2006, 12:07 PM
Well atleast your UV is doing a thorough sterilization.

I wonder if a To much of a clean pond can be a problem. The Immune system would certainly not be used as much, and when some big virus comes around, maybe the immune systems of the fish wouldnt be strong enough for the intruder, and ultimately cost its life.

What do you people think?

02-21-2006, 01:26 PM
Someone wrote an article on that a while back for that British magazine....ahhhh, Nishikigoi International I think. Let me see if I can find it.

(Searches hard drive and draws conclusion that it is at home)

I'll have to edit and add it tonight.


02-27-2006, 08:07 PM
hmmm well hurry it up!, hehehe just playing
take as long as you need.

02-25-2008, 07:56 PM
Steve must be stuck in traffic. We're waiting.:D: