Cedar shingles

[andyroo]

Folks,
Tell me about how fish in a planted (lotus & lilly) pond might/will react to rainwater coming off an old cedar shingle roof. I'm guessing the moss, plants etc.. on the roof will be good in conditioning the water, and that soots, dusts etc... will be taken out in the filter (lots of turnover and charcoal). The roof is not guttered, so only the roof directly over the pond will drain into/around it. Retention time on the roof would/should be no more then seconds, but for after-drips.

Red cedar is very chemically active- any thoughts on how new/fresh shingles will affect fish? Will plants and filter-charcoal be able to deal with this?

Thanks.
A

[Diana]

I think I would let a new roof age for about a year before allowing that water to land in the pond. After that the wood has probably lost enough stuff that any remnants would weep out slow enough not to be a problem.

Local climate is a long dry summer, so I let a couple of rains go by or a single really big storm to wash away most of the accumulated debris. If your rains are more or less year round, then there should be no problem at all. The debris gets washed into the pond a little at a time, so the filter can deal with it.