| Jay,
My pond is made of gunite with plastic cement to seal and give a smooth finish. The alkaline in cement leaches and mixes with the pond water keeping the pond water on the alkaline side of the chart. koi prefere this water hardness. Remember a new pond must be cured before introdusing koi. There after only small amounts of alkaline will be introdused into the water. I always recommend to folks that are building a linner pond to add some cinder blocks to the system [not in the pond ]I use 1 per 1000gal. Change out once a year. Oh yeah, I have a 1000gal holding tank made from linner.
Back to the subject of clay. Use it as an additive and your water quality will only improve. A sound filtration system and clay will give you sparkling water.Do a internet search on Bentonite and you will be amazed at its uses. I prefere Refreash powder from Japan. I also use Dixie Bond [calcium]Southern Bentonite. I alternate between the two. Use 2 1/2cups per 6000gal. Water will turn cloudy but goes away in a few hours. Do not waste your money on tileing a pond unless its at the water line and above for looks.
Louie |