Question
I was told not to have morter in my pond for it would be harmfull to the koi but can I use morter in my waterfall creation?  Thanks for any help

Answer
Mortar will leach chemicals that raise the pH and hardness of the water.  If there's just a little leaching, no big deal.  A lot can kill the fish.  To make the mortar less toxic after it's dry, you can leach it by rinsing it repeatedly, draining, refilling, etc.  You can also wash the mortar and any cement areas with vinegar.  Take a bucket with vinegar water and scrub brush and scrub those areas down if you can.  Rinse well and repeat until you think it's safe.  The mortar may foam up when it is acid washed.  Once the pond is set up and running a few days (without any animals or plants), test the pH.  It should be between 7 and 8.  If it's much higher, the mortar may be at fault.  If you want to try an alternative, they sell various pond sealants that don't use mortar and should be safer.

Robyn
fishpondinfo.com