Question
I have an 8 foot diameter pond, about 18 inches deep.  A submersible pump moves the water uphill 35 feet to a 4 foot diameter pond (10 inches deep) and the water goes back down to the lower pond via a 2 foot wide steam bed.  All of the above is lined, and is about 13 years old.  Recently I have had to refill the pond more than once a week, which is time consuming, never mind the waste of water.  Short of rebuilding the whole system, where would be the most likely sources of a leak -  or how do I go about trying to find it?  Thanks.

Answer
Hi Tim,

Look for cracks wherever the liner has been exposed to light.
There are certain dyes that could be used to detect leaks, that is, if you don't have any fish on it.
Ask you local pool supply store and they will be able to tell you about them.

You could also let the water go, and whenever it stopped, the leak should be around that level.

Good Luck!

Carlo