Rich,
Assuming that you haven't changed the flow rate though the UV and that your new bulb is the correct bulb and is not old then I would guess that the Quartz sleeve has a coating of lime on it. To check this remove the UV unit from the piping and with the light off look in the two 1.5" unions to see the quartz sleeve. It should be crystal clear. If it is not the sleeve will have to be removed and cleaned off with acid.
Mike

Mike,

The Quartz sleeve is crystal clear, I took the unit apart when I put in the new bulb. Changed all the gaskets.

This morning the pond seemed somewhat clearer. I only changed the bulb last Wednesday. Maybe I need to let it run for awhile more, see what happens.

I'm just frustrated, not being able to see to the bottom of the pond.

Thanks,

Rich

If it's only been since wednesday, it just needs more time. You should be clear within a week or so at the most.

Rich,
It could take up to a week for the UV to clear the pond.
Mike

Thanks Guys,

I guess I'll be patient for awhile and see what happens. The fact is this is the second bulb this season. I ran the first one for over two weeks. The pond got progressively worse. I called the guy who sold it to me and I suggested the bulb was bad, it glowed but didn't work. To his credit, he sent me a new one. That's the bulb that is running now. I hope it works.

Rich

My pond used to get green and murky in each spring... I determined it was due to not having enough plants come out of dormancy early enough to use the excess nutrients that the algae was feeding on. I added 3 marsh marigold plants and have not had a problem since. The marsh marigolds are one of the first plants to "wake up" in the spring and I no longer have a spring algae bloom. They are also one of the first flowers in my garden each year.

Enough bio-filtration can prevent the spring algae bloom as well. You don't need plants to prevent it. I have a single 57 watt UV in my 9000 gallon pond and no UV at all in my 5000 gallon pond and never get an algae bloom in the spring.

Since your 1,500-gallon pond stayed clear for two seasons with the Emperor Aquatics 25-watt Smart UV, I’d check a few things before replacing the unit. A new bulb can light up but still may not work effectively if it isn’t the correct replacement or isn’t seated properly. Also, check the quartz sleeve for dirt or mineral buildup, as this can reduce UV performance. Make sure the water is flowing through the UV Sterilizer at the recommended rate and that the pump and filter are working properly. Since the unit is installed between your skimmer and biofalls, check for any changes in the plumbing or flow. Green, pea-soup water is often caused by suspended algae, and a properly working UV system should help control it. If everything checks out, confirm the bulb type and replacement schedule in the manufacturer’s manual.