I've been using pea gravel, covered by river rock for a number of years now.
No problems with Koi. They seem to totally ignore the pots, (as there is no
clay to root in).
There is no fouling of water. No algal bloom from leached nutrients from
soils. I have found it easier to divide the plants. It is much cheaper than
"aquatic soil". There is no soil decomposition.
Disadvantages? It weighs slightly more than clay.
For lilies I add fert. tabs once/month, and get same degree of blooming as
when I had them in clay (with second season).
Another thought...
Happy ponding,
Greg


"Priscilla McCullough" wrote in message
...
I bought some potting soil today to plant some of my lilies in. They were
out of the dirt I normally buy to do this.
I got to thinking though if there is anything in the potting soil that
might
harm the fish.
The only thing I see is that it has peat in it. Do you think this could
harm
the fish by making the water to acidic?
Priss