UV might be one of the reasons why you have a string algae. UV kills anything that is floating including small cell floating algae; I believe this is the same type of algae that causes pea green water when the algae's population becomes very high.
If ya are always running the UV light, then ya likely have no small cell algae to compete with the string algae. Lack of competition might be the reason why your string algae gets so bad.
I only run my UV light for 24 hours every 3~4 weeks so that the small cell algae population does not get too high, turning my water green, and I hope this is allowing some of the small algae to be around to make a difference, maybe I need to run it for only 12 hours.
I would be careful with the peroxide dosing. That linke waterbug mentioned is very interesting. The hydrogen peroxide only dissolves when it is in a reaction to something else; if you lack this "something else", then the peroxide will stay in your water longer meaning you may overdose eventually. From that hyperlink mentioned, this is more likely to happen sooner if your pond has just gone through an extremely thorough cleaning or is completely brand new. I suppose the advice for peroxide dosing is, "be sure ya wait a few days or more before your next peroxide dose". Even though the hyperlink talks about how much peroxide it would take to overdose, the fact that the hydrogen peroxide can linger around a long time causing an overdose easier; this is what scares me away from it since my water feature is so new.
I use the new Pond Oase vaccum. I think offhand it is like 3 or 4 horse power (don't quote me on that), but it is very powerful with twin chambers so ya never have to stop. I connet PVC to the suction portion to reduce it down from a 1 1/2" sucker to a 1/2" sucker. Without the reducer, I was pumping out more water than debris; heh, emptied my 430 gallon water feature by the time I was finished. Now, I only lose about 80 gallons and the suction is crazy strong since I reduced it. I can get all the gunk between the rocks and leaves and everything crazy easy. Oase is quite expensive but worth the money. I have never had any issues at all sucking up small gravel, small twigs, large clumps of long string algae, and big clumps of leaves. At the end of the vaccum's drain hose, I put some PVC pieces on there where I can hook a 2" tubing with a very big nylon laundry at the end; this sits next to one of my trees so the water is not wasted. My next project is to set up a filtration of batting and other stuff so I can recycle the water back into the water feature. If ya have a very big, very deep and very wide and very long pond, then ya might lose too much suction due to the length of the suction apparatus; this is the main problem I read about it for people with much bigger ponds.
Plant in a pot, keep top of pot above waterline, trim sprigs that fall into the water. No algae problem, pot is covered by plant. Pretty hard to tell the plant is above or below waterline. Lot easier to maintain imo.
Very good idea man. I think it will look nice too when it drapes, hiding the pot a bit.
Anyone got any advice for the Maris Tail ?? It is an underwater oxygenator and I think is a variety of Anacharis. Right now, only a very little bit of algae is growing on it, hard to tell if it is the really fast growing string algae.
