We have a 200-250 gallon outdoor concrete Koi pond that was re-surfaced exactly one month ago. Our 14 fat Koi have been living in an 80 gallon Rubbermaid tank. They want to go back to their nice pond, but I want to make sure I set the water chemistry correctly and I want to make sure that the new concrete has completely leached.
After the new concrete had set, we filled the pond with plain tap water and occasionally stirred and scrubbed for a month in the cold winter weather. The water surface froze. When it thawed we poured in a gallon of muriatic acid, scrubbed some more, then drained the pond and filled it with tap water again. We let that water sit for a week, scrubbing a bit.
Now we want to replace this water with fresh tap water and start adjusting the chemistry to dechlorinate and achieve the proper pH level.
My questions are (1) has the concrete cured sufficiently so I don't have to worry about further leaching (which would upset my attempts to get the pH set correctly); and (2) what should I be adding to the tap water now to get the pH in the proper range?
After the new concrete had set, we filled the pond with plain tap water and occasionally stirred and scrubbed for a month in the cold winter weather. The water surface froze. When it thawed we poured in a gallon of muriatic acid, scrubbed some more, then drained the pond and filled it with tap water again. We let that water sit for a week, scrubbing a bit.
Now we want to replace this water with fresh tap water and start adjusting the chemistry to dechlorinate and achieve the proper pH level.
My questions are (1) has the concrete cured sufficiently so I don't have to worry about further leaching (which would upset my attempts to get the pH set correctly); and (2) what should I be adding to the tap water now to get the pH in the proper range?
