Algae in Pond

Hey Folks, new to pond and have a question. I have a small pond, approx 140 gallons that I set up about 1.5 months ago and having algae blooms (See Pics). Those pics were taken right after I had just cleaned out a bunch of algae, its typically floating covering about 40% of the water surface. I have about 300 gph flow, plenty of circulation and surface agitation and have my well overflowing the pond for 1 hour every night. Its doing more than a full water change nightly. As far as stocking I only have about 7 sicklets of varying sizes. I was huge into salt water reef tanks several years ago and at least then my well water I used for top off was always very good as far as nitrates, nitrites, ammonia, etc. I haven't checked it lately though. I also have a Papyrus plant and a unknown lily. What may be causing the bloom ? I suppose I should start by having the pond water tested but again, I'm doing over 100% water change nightly... Could the well water be the problem? Thanks !! I appreciate any help !

Vendetta

String algae is normal in the spring. In my pond I just kept after it by pulling the excess and leaving the roots. In time, it will level off and pretty much go away. Get some floating plants to keep the sunlight down and have plenty of circulation and in time there will be only a trace of it left. Koi love to eat it and mine are very healthy.

You also have to realize that with this small of pond, it is much more difficult to maintain water quality and clarity. 100% water changes are risky and not recommended unless there is no other choice.

Thanks Dave !