Question
I have recently experienced a problem of water loss during the night. I have a 35 gallon pond, which is in ground. I have lost about 10 gallons in a single night. It is not from evaporation or splashing from the fountain. It does not occur every evening, and I have yet to experience fish loss. The floating plants have been disturbed, but not seriously damaged. My local supplier recommended I run my pump constantly, and I wondered if this may have attracted wildlife to the water? Any ideas?

Answer
Mark,

Let's look at this logically.  Where is the water going??

#1 - It's leaking out through a hole.
#2 - It's blowing or splashing out of the pond from the fountain at night.
#3 - It's evaporating.
#4 - Something's drinking it.

From what you describe, these are the only options that I can see:

#4 is unlikely, that would take an awfully big dog or maybe a cow or something, lol.

Not enough loss for #3.  And if you are absolutely sure about #2, then it must be #1.

Hope this helps,

John