Bath Tub Water Temperature

Today I fixed something in my house that has been bugging me for most of the 9+ years we have lived here. In the beginning I understood that I needed to leave things the way they were because I had small children. However I no longer have small children and the medium sized children I now have been complaining about this situation lately. What situation??? The bathtub water temperature, thats what situation. Our home has 3 full bathrooms. Two of them have only showers. The kids bathroom is the one with the bathtub. For several years when someone wanted a hot bath they had to take a cup or bucket and dump the HOT water from the sink into the tub. The tub would only run warm water. NO MORE! I fixed it! It took some figuring out to get the job done, but as So would say "yea me."