Limestone?

[perplexed ponder]

I thought I remembered that limestone is not good for use in the pond, is that correct? A contractor wants to install limestone and I wanted to check with you guys first!

[emm]

I too have heard that limestone is not a good choice for a pond however all the rocks around my pond are limestone.  The rock shelf goes right into the water and the waterfall is made of three large pieces of limestone so water is always in contact with or flowing over the limestone rock of my pond.  The pea gravel in the large gravel filter/bog area for the pond is also limestone.  I have not noted any ill effects to plants or fish.  My pond is about 9 years old.  The rainfall around here tends to be on the acidic side so the limestone does have a buffering effect which may be why it works for me.

Not sure how my pond compares to yours but for me limestone seems to be alright. 

emm

[Michiponder]

Most ponds in this part of MI do not need much buffering due to the hard water we have.  I am surprised a landscape guy would recomend it due to the fact that it often crumlbles when it gets wet and goes through our long freeze/thaw cycles.  IMHO it is not the best choice for in pond use.

Mikel

[howardTheHumble]

Limestone varies a lot.  I wonder how much it effects the ph once it is covered with a bit of slime etc.