From what I understand, UV lights wear out, so you might try replacing that.

Also, do you have lots of plants? Plants help quite a bit.

If you have fish, watch that water temperature! You may need to shade the water to keep it from getting too warm.

I have replaced the bulb, I do not have any plants as the fish keep eating them. and no shade, I am not sure how to shade the pond.

I had the same problem with my pond. After trying every so-called natural method, non of which worked. I went to my local pond shop and bought some algaefix. After one week of treatment the algae was all dead. I had to clean my filters most every day to get the dead algae out. Now I treat the pond once a week to keep the algae out and my pond is once again crystal clear and my fish are as healthy as ever. It works very well and does not harm your fish

The stuff saves me tons of work in all 3 of my ponds.Just remember to use it EXACTLY as the label tells you. Lots of air to as the dieing algae causes an oxygen drop.

I have gazebo over my pond =less work and no green water and no UV light just a barrel with bio-ball as a filter and bog plants

I use algaefix as well and a UV light in spring. You only need to replace the bulb not the whole unit. Shad it in the heat and sun of summer if you can if not lots of lilies will help shade the water and keep the algae in check. Be sure to follow the directions on the algaefix to the letter and it will do you a good job. It will not harm fish or plants if used as directed.

IF used as directed is the key phrase. I've read dozens of posts by people over the years who have killed their fish and/or plants with Algaefix. I would never use it personally.

Fish won't eat every single type of plant unless they are starving...Plants will not only help reduce algae they look nice and more natural than a bare pond and help your fish hide from predators. Fish who are constantly exposed also can feel really nervous all the time.