How to clean a new pond???

I built a 22x22 ft pond last year, putting pump in this spring. There are a
few small goldfish already in it, 5-6 inches. There is a layer of green
algea on the bottom. Do I need to vacumn this all up before adding the pump?
How much organic matter is ok?

I will need about 80 feet of tubing to run the external pump and supply the
four foot high waterfall and 60 stream. The price of this tubing is high
from the pond industry. Is there an alternative tubing source for the same
product?

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Steve Shapson