String/Blanket Algae Help Needed ...

[Arthur]

Someone asked me to help with this enormous water feature: 50'-60' water stream, waterfall at top, pond at bottom. The thing is infested with string algae.

The waterfall/stream is powered by two submersible pumps moving a total of 10,000 gph from two skimmers to the waterfall weir containting a lot of volcano rock infested with string algae. There are fish in the lower pond.

I know string algae strives on DOCs, so my main solution to the problem is to remove as much decaying debris as can be.

Proposed solution (which has to fit into the landscape):
1) install retrofit bottom drain to pump the "stuff" out of the lower pond;
2) take all the volcano rock out of the waterfall;
3) circulate the waterfall rushing water through a bead filter;
4) add a UV clarifier since the dying string algae will give place to monocellullar algae

All those who fought string algea, what do you think (managing the pH is not possible as the added water comes from a local well)?

Thanks for any help,

[dick benbow]

Arthur,
Does this water have koi or goldfish in it? So often heavy amounts of phosphate come from the food. If not it may very well be in the water source. I think your thoughts are right on with your plan. I think the biggest offender in my experience is the gravel which traps debris. Just cleaning that out should be a big help. I'm not sure with thread algea that the UV will make much of a contribution, tho Sounds like it may get a strong sun influence from the west.
An attractive fence that could cast shade and support some blooming vines during the heat of the day might help.

[keokoi]

Subermisble Pumps..

Arthur, where are these pumps pumping out of?

Full sun on the pond?

[Arthur]

Two skimmers on the lower pond with a Little Giant 16-CIM each. There are a dozen small koi and some goldfish in the lower pond.

Ther water feature is two years old and in full sun all day.

I forgot to say that the whole thing would be thoroughly cleaned before implementing the plan above. The UV is for the inevitable monocellullar algae expected after cleanup and removal of the string algae.

My idea is to get all of that organic debris out and then install a system that would keep it out (well most of it given the circumstances).

Any other helpful advice?

Thanks,

[Allen2909]

I'm in the 3rd year on a pond and just developed string algae after trimming limbs over the pond thus allowing more sunlight. The use of Koi Clay greatly helped clear it up.

[S. Stone]

This year, my quarantine tank (an 8 foot Pearls of Paradise show tank sitting on the deck right next to the main pond) developed BAD string algae. Never had it in either the pond or the tank, before, in almost nine years of keeping koi. It just appeared! The main pond never got it. The string algae gradually went away in the tank when Epsom salts were dissolved and added to the water.