Nigel Molesworth wrote:
I've just started to get my swimming pool ready after the winter. I
was hooking out a load of leaves then spotted a pair of dead rats!

Any suggestions on the ppm level of Cl I need to make it sake?

Fr sake, its the alcohol, not the chlorine level you need to increase.
Around 15% IIRC.

Dead rats are an essential part of cider making allegedly, so look
forward to a vintage year ;-)