Hi just connecting new carport guttering into tanks with live stormwater drain. I’ll be using 90mm stormwater pipe and being as it’s pretty flimsy stuff should I put some sand in the trench with the gravel so it doesn’t pierce with the stones, or is it ok to just use gravel?
Pipe will go from roof height down into ground, along about 8 metres then up into tank (which is lower than guttering)

