I think some may have misunderstood my post so I will try to clear the misunderstanding. I did not say anything what so ever against UV sterilizers. There is no standardization in pond UV's. A manufacturer can claim just about whatever they want when it comes to clarifiers and when it comes to sterilizers they just have to have any test that shows that they achieve 22,000 units for sterilizing the green water. There is no standardization of the testing method to be used such as the Bolton standard that is accepted by the FDA and the EPA for UV used in other applications. To my knowledge there is only manufacturer that is using the Bolton standard to rate their UV's. If sterilizer are not held to standardized testing clarifiers have no standards. They can claim anything they and do in a lot of cases. By all means I would encourage anyone to use UV but if are going to invest the money into an UV unit get a sterilizer that is sized for your pond and flow rate. And yes a good sterilizer can slow down the spread of some pathogens. Yes some bacterias are sterilized at levels lower than green water and parasites can require levels far higher. As an example ick requires almost 5 times the level as green water. Clarifiers may or may not work and if it works at the max gallons and flow rates that are advertised than you problem would not need one. I have seen them claim very large pond with very high flow rates on a very small wattage bulb. The little bit that I know about UV tells me that there are a lot of units on the market that are a joke. What needs to be figured is the length of time that the water is in contact with the UV radiation, the amount of radiation that the unit can produce at the proper wave length, The temperature that the bulb is operating at, the clarity of the water that the UV is penetrating, and the quartz that the light is passing thru. The other misconception I hear a lot is that UV kills green water. I am sorry it does not kill anything in any quantity but it does is destroy the DNA so that the organism can not reproduce. The original organism still has to die on it's own. Mike

For green water a UV should clear water in 3-5 days imo. The change can seem sudden if you wake up in the morning and can see the pond bottom. What really happens is the algae is killed pretty fast, maybe 8 hours. But it takes some time for the green to decompose out of the cells leaving an almost translucent cell behind which are also smaller. Some clump and sink. What UV do you have? 10-14 days bothers me. Clarifier is not a precise term, so sellers can get creative. Most manufacturers provide info on flow rates for both sterilizer and clarifier. I always use the sterilizer flow rate when comparing units, apples to apples. Taking 10-14 days could mean a very weak UV for the advertised flow rating. In a bright green pond single algae are that, single cells, easy to get a high UV dose. After a year many cells will have clumped together into what is called "colonies". They do this as protection from the sun's UV. It also gives them some protection from UV filters as it takes many more trips thru the filter. Add a bunch of other suspended particles, plus a weak UV, could be issues. Diggery is right, not enough info to really know anything. A red flag to me is a pond that hasn't been clear in a year may appear green but be a combination of things. After cleaning different ponds for awhile you're able to tell a lot from just seeing the water.

Coxy, I would guess that you have a Savio standard skimmer. I am guessing that you have 2 50 watt UV's. The thing that I can not know is if you have Savio UV's or Emperor Aquatics UV's. If they are Emperor you may be able to find someone besides Al Zimmer to sell them cheaper. Al is the brother of the owner of Emperor and everyone watches that he is not selling Emperor products cheaper than MAP pricing. You may find someone else that won't advertise any cheaper than MAP but will sell them cheaper if you contact them. UV bulbs by most manufacturers are to be changed when they drop down to 80% of their new output. Most of the time this is 9,000 hours of use or about 13 months of use. There is no way to tell by looking at the bulb if it is still operating at the level that is needed. The metal that is coating the inside of the bulb at the ends has nothing to due with the age of the bulbs. Whatever you do don't look directly at the bulb when it is on even for a short period of time. The UV will be burn your eyes very quickly and you will not know that it has happened until later. Mike

It sounds like the 40 watt UV lamp is strong enough to eliminate your suspended algae in a few days. I have a similar strong system on a seperate pump. I run my UV if algae appears and shut it off when the water clears. I know I can control algae within a few days, so I don't run my UV unless I see green. If I catch the bloom early I can eliminate it relatively quickly. I would run the UV system until the pond is clear. Once clean, you can shut down the UV clarifier and see what happens. You can always re-start the clarifier if the algae returns. Once your plants are established, the aglae problem should go away. I seldom use my UV clarifier, but I'm glad its there if needed.