Question
I installed a concrete in-ground pond about three weeks ago and have been changing the water about twice per week since.  I also purchased a water-based sealant that I haven't applied yet.  I'd like to make sure that a good portion of the lime has leeched before putting on the sealant.  Is there anything I can add to the water that will help further reduce the lime prior to applying the sealant? - I was thinking something like the cleaner "C.L.R." that removes Calcium/Lime/Rust buildup and stains in showers, coffee pots, etc.  Any suggestions?  I am anxious to get the pond filled and put some Koi into it.

Answer
Hi,
My pool is concrete and what I did was scrub the walls and base with a strong solution of acetic acid (VINEGAR), you don't say how big your pond is but depending on the size pour one or two bottles of acetic acid in the water that is allready in your pond and with a big stiff sweeping brush give it all sides and base a really good scrub leave the water in over night scrub again and empty, then fill again with fresh water and leave over night the next day empty it and then fill and let it stand for a couple of days and then it should be okay to add your koi BUT first put a small fish in the pond for a couple of days and see how it behaves but every thing should then be ready to add your koi.you can visit my pond if you wish at
http://koi-z-are-us.20m.com
Happy koi keeping George.