Quote Originally Posted by Poolsean
It's harder for algae to grow with moving water (stream in your case).
You'd be better having the water tested first. High levels of phosphates (from animal droppings, decaying vegitation, fertilizer) or phosphates (fertilizer again) will get you in trouble from the get go.
Not to mention the nitrates from fertilizer!
(I knew what you meant so I took the liberty of correcting it. I've made many a typo like that myself!)