k1w1k1d:Just have to remember that you would be paying full daytime rate to heat the cylinder.
Thanks for finding that I'll look in to it at some point. Like I said it's rare we have guests stay, at some point we will have visitors form overseas for a decent length stay. We aren't bothered about paying for it with day time power it's just the pain of knowing we wouldn't have water if people stayed. When it's just us the ripple relays fine now we know it's a thing and are aware to not use the hot top for things like rinsing dishes before they go in the dishwasher.