I plan to install a shower pump & currently have a 25 gallon cold water tank. I understand the tank may not be big enough to feed the shower & hot water cylinder for a longer than average shower. Instead of installing a bigger cold water tank is it an option to fit a second feed into the tank split from the exising pipework to a ballcock? Valves don't really allow a decent flow rate & doubling up would surely help to refill the tank. Can't beleive someone has'nt thought of this before, so perhaps there's a good reason this won't work. Thanks in advance for any advice.