Question
durring this drought period is it safe to top up my pond with tap water. Will this effect the eco balance of the pond?  

Answer
Yes, add water to your ponds.  If you're adding more than 10% of the volume as tap water, be sure to add some dechlorinator to render the chlorine non-toxic.  I top off my pond daily in the high heat and at least weekly otherwise.

Robyn
fishpondinfo.com