Hi Bob,
Thanks for answering. Are hair algae and string algae the same thing? The salt concentration reading I got was .02 and I guess it is supposed to be .10% . Would solar salt be ok to use for this? I can divert the water so it does not go into the pond, and I have pump and blossom head spray I can keep running to arreate the water. so this could be a closed system for as long as I wanted. I do have 2 small bundles of barley straw in now , but I guess it takes some time to work. Do you think I should add more salt? Also,. if I block out the sun, would this help? Thanks again for your help. If you don't like me sending you these questions, let me know!
Hal

Hi Hal,

Yes, hair algae, string algae, blanket weed, all the same stuff. Shade will indeed help.

I tend to operate on salt concentrations in ppt or lbs per 100 gal. Percentages just confuse me.

Salt is not going to affect the hair (string) algae at all. I think the stuff likes salt. See the FAQ on salt for conversions. I like 1.88ppt for a running concentration during the season, and 3.125ppt for a spring tonic.

Barley straw does indeed take some time to work. The algae inhibitor is a breakdown product of the straw and bacterial action. The problem is that you'll lose the charm and ease of your fresh water system if you block it off, and you'll end up with a brown tinge to the water. I still think that raking out and composting is your best aesthetic bet, just a little more labor-intensive.

Aeration also won't affect the algae, but the fish appreciate it!

See also this excellent article Algae and Their Control in Biological Ponds.

Bob Passovoy
President
MPKS