what kind of algae

[LynneNY]

is this?

The other day, I noticed that the rocks under the waterfall were VERY green!  Today, I was able to scrub them clean when my husband turned off the waterfall to clean the filter.  It was very slimey, and what is the darker green area?





My husband put in 2 UV lights in the skimmer about a month ago and the pond water is now nice and clear, so we were surprised to see all that on the rocks.  That is actually much less than a few days ago!

Here is an after picture of the nice, clean waterfall.

[tranquility]

Looks like the beginnings of blanket algae--its the good kind...its almost impossible to keep the falls from getting algae...UV light only keeps down the suspended algae-the kind that turns the pond green...not blanket or string....on the falls I just take a brush and clean off the falls once a week....
Lawanna

[LynneNY]

Thanks so much, Lawanna!

I researched blanket algae after your reply, and that is exactly what it is!  It helps to know the name, and what should or should not be done.  One of the articles says it's commonly found in ponds with UV lights, so it's no wonder that we have it now, now that we have had the UV lights in for about a month.

[tranquility]

I've never had a uv light and I have it in all of mine...in a few years it will litterally feel like a carpet in the pond...Its great to get into the pond and not slip and slide once the blanket algae takes hold....but, on the waterfalls it can be the pits...only thing you can do is just take the brush to it when it gets too bad....
Lawanna

[PHYLAL]

I you are fortunate enough to have a pressure-washer, they work very well, and in my experience, they algae does not return as quickly, BUT IT WILL RETURN!

[LynneNY]

Interesting about the carpet effect - I went into the pond for the first time yesterday - my husband usually does that but has bad sciatica now - and I was surprised at how much I was slipping around!

Phylal - my husband does have a power washer - good to know about that too.  I used the strongest stream on the hose yesterday after I was finished scrubbing, but the power washer would definitely work better!  Thanks!

[frogman3]

Lynne, turn you water fall off pour enough hydrogen peroxide 3% on the algae to coat it turn the falls back on after 1/2 hour in a few days it will be brown and it will come off real easy with a brush. If you want to know more about hydrogen peroxide use in a pond do a search on this forum. 3% is what you buy over the counter at any store. The algae will not start to return for several weeks and will not cause any harm to plants or fish.