IIRC, the Cl treatment levels in my County are 0.1 to 0.2 mg/l of Cl. I'm on well water so i dont worry about it. Cl is very volatile. if you run the water overground for some distance before it enters pond, most of the Cl should escape, and this will also help oxygenate the water. if i was doing this, i'd look to run the water at least 10 feet over a gravel surface, i've also heard of running the water through a series of screens first as well.

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