Algae/plants question

I've been helping a friend setup/maintain her pond, and I've asked a couple questions on here about other things. I know plants help keep the water clear, but I was wondering how long it takes and how many plants.

Her pond is at least 1500 gallons, but I really have no clue exactly how much it is. It could be closer to 2000g. Anyway, it's approximately half shaded all day, and the other half has shade for about 2-3 hours but sun the rest of the day. She has a fountain pump with a prefilter on it but no real filter (yeah, I know).

For plants, there are 3 gallons worth of anachris, some cabomba, 6 water lilies, 3 pickerel, about 1/2 gallon of bladderwort, and a handful of frogbit. There was a 1/2 gallon of duckweed, but that disappeared pretty quickly. There's maybe a couple handfuls now. She has 4 or 5 small goldfish (all under 3") right now. She'd had two 3-5" goldfish and a 10-12" koi that died after she added some sort of algaecide (Tetra I think) and then had the pump off for 2 days. She thinks it was the pump not being on that killed them, but I think it was a combination of the algaecide (possible overdose?) and the pump being off and possibly some unknown factor.

The majority of the plants were added about 1-1/2 weeks ago, but the water was still very green. You can see down further into the water, perhaps up to a foot, but it's terribly hard to see much. :crazy: This was on Saturday that I saw the pond (a week after adding the plants). I'm not sure if it has cleared up much since then. She said she did almost completely drain the pond and refill it because she was moving the pump into the deeper part of the pond and needed to set up a block to support the pump and get it up above the waterline. That was probably the reason why the water was clearer, more so than the plants.

Should I have her add more plants or wait to see if they help first? Am I being too impatient? I want to help clear it up because she keeps using the algaecide, and I hate using chemicals like that, especially when we're not sure the exact gallonage of the pond. I'm not real worried about the algae since it won't hurt the fish and they might benefit from green water, but I do worry about the algaecide's effect on the plants and fish.

Thanks, I think she mainly just wants to be able to see the fish once in a while. Right now, you can only see them as a vague orange blob when they come to the food (sinking pellets and sometimes veggies like cucumber). I have more frogbit, but there's a lot of surface area to cover. I would estimate that the pond is at least 10 feet by 6 feet across, maybe a little wider and longer. One end is about 2 feet deep and drops to 4 feet deep about 1/3 of the way across.

Ain't that the truth! I had some in my 75g, and it covered the top within 2 months, starting with only 3 plants! I think she bought 2 plants at one of the local greenhouses, and hyacinth too. Those multiply like crazy too, and they shouldn't be a problem up here in Wisconsin since they freeze out early in the fall.

Just thought I'd share an update. I gave her almost a gallon-sized bag of frogbit from my 75g tank (started with 2 frogbit about the size of a deck of cards each 2 months ago, completely covered the 75g surface), and she called me the next day to say that it was already a lot clearer!

Which is really good news since she had been getting really frustrated with it lately. It has been leaking and there was something funky going on with the pump and a dead spot in the deepest part of the pond and fish death and a few other things. I'm pretty sure that the fish death is due to her buying small feeders (at most 3" long) and also to using the algaecide.