Question
Hello,
We have an in-ground cement Koi pond/fountain that was empty when we
recently purchased this property.  We sealed it with a water proof deck paint
and installed a new pump.  Whenever we use the pump, the water will fill with
suds.  We've tried scooping it out and re-filling the water to no avail.  We've
also tried the pond starter kit, but nothing seems to change the situation.  We
are only looking to grow water plants and not have any fish, but would like to
eliminate the suds.  Any thoughts would be appreciated.
Thanks so much,
Mark

Answer
What exactly was that paint?  If it wasn't made specifically for ponds, it's probably causing the problem.  New cement will leach; I don't know how old your pond is.  Sealing it or putting in a liner is a good idea to prevent leaching of the cement.  You can't use deck paint though.  The paint will leach organics into the water that can cause the foaming.  It's also toxic to animals and plants.  I suggest either resealing the pond with the correct sealant or putting an EPDM liner over it all.

Here's a link to one place sealing the liquid rubber "paint" like you should use:
http://www.pondtechnology.com/pages/cim.html
I'm not positive that painting that over the old paint will prevent leaching of the paint but that company would know.

How big is the pond?  
Good luck!