I have an 850 gallon concrete fish pond with a waterfall and small pump, which was installed about 6 months ago. I started with 9 goldfish and now have a couple of dozen little ones swimming around. I have plenty of anacharis, three water lilies, horsetail and some water hyacinth.
The water has always been green from the algae, and I had hoped it would be clear by now. The other day we had a power outage so the pump was down for about 24 hours. I noticed that the water started clearing up and when the pump started up again, it turned green again. Now I'm wondering if the pump is actually stirring up the algae and making things worse and whether I should vacuum the bottom. Any suggestions welcome.
You need to get a small UV light. It will kill any algae that greens up your water. Look on ebay, they're MUCH cheaper than anywhere else (even though they have them in the pond dept at Lowe's) For an 850 gallon, you will only need a 9watt, although an 18 watt would be fablulous. :) Look through some of the other water forums, we just had a long conversation about it in one of the other posts.
Kim-I've had a pond for 13 plus years just recently had a problem with green water. MM convinced me that a UV light would help, boy was she right. I put the light in my skimmer and within 24 hours I began to see an improvement. Go for it, you'll be happy you did.