| JR... interesting points, and fair.
Shiromuji... now you've opened up another can of worms! ;-)
OK... the objective here, is to change enough water to maintain a reasonable TDS differential between the pond water, and mains water. So, if your pond is more heavily stocked, then more water will be needed to keep the TDS in check. Otherwise, the TDS will just climb and climb forever, and growth will slowly grind to a virtual halt.
So, I would say that Ian changes (to overflow), about 500 gallons a day in order to maintain a TDS of 80ppm. Colin changes probably about 400 to maintain a sub 80ppm TDS. This is a constant trickle to overflow. Jon Mak is low stocked, so in his 5500 gallon pond, changes less than 100 gallons per day. James Carter is also low stocked (10,000 gallons), and changes a negligable amount of water.
The TDS meter is basically used as a 'water condition' meter. It is impossible to quantify how much should be changed on a pond, without one of these meters.
Hope this helps?
Mike. |