Our bath and en-suite shower is fed from a cold water tank in the loft. My kids have decided they like the shower but stay in it a long time. This causes the tank to empty and airlock the shower pump. I then have to the disconnect and bleed the the cold water feed. I there a way to make the water tank fill quicker so it doesn't run out? Can something be adjusted or will it require a new fill tap/valve? If so any idea how much this should cost?