View Full Version : Raising pH in Pond

01-04-2011, 10:15 PM
Hi, I have a pond which had 7 Koi in it. They have been looking a little under the weather recently so I checked everything and the pH had dropped below 7. I had read that they prefer alkaline water so I am looking to increase the pH by adding in some limestone. (the fish seem fine now, but I still want to get the pH to where it should be)

Can anyone let me know if adding the limestone is going to be a problem at all and if it is ok, how much should I add?


01-04-2011, 10:34 PM
What pH did you measure?

01-05-2011, 12:44 AM
it was 6.8

01-05-2011, 01:50 AM
What was it before? Generally a stable pH is more important than an exact value. Unless it's dropped recently I wouldn't mess with it - you're more likely to send it too far the other way.

01-12-2011, 03:10 PM

Pond's naturally have a tendency to move towards acidic. How quickly depends on the source of your water (whether it is hard and buffered, or soft) and your stocking/feeding levels. It is the by-products of your fish that releases lots of free Hydrogen atoms into the water - causing your pH to drop. Adding crushed shell or limestone to your filter should do the trick. There are more details here: http://www.watergardenersbible.co.uk/fish-health/clays-and-buffers-in-a-koi-pond/

01-12-2011, 05:11 PM
Could you give us some specifics about your pond please.
How many gallons
Surface are or dimensions
How big are the koi
Any other fish
Water ph from your tap
What size pump
Filter type
Does the pond collect leaves
How old is the pond and fish

01-12-2011, 06:11 PM
Do you do perform water changes?