I would make an adapter that would allow you to connect to the hot and cold at the same time
go to your local garden senter and buy yourself a Y fitting for a garden hose ( most Y connectors I have seen has a valve on each side that will allow you to control the temp)
then you would just need two small hoses that will connect to the water lines themselves and then attach the Y hook up the hose you fill your tank uyp with and your set and it should not cost to much .
I have thought about this alot actually because its basically the same system I put together for my 360 gallon tanks auto water changer
Hope this helps
go to your local garden senter and buy yourself a Y fitting for a garden hose ( most Y connectors I have seen has a valve on each side that will allow you to control the temp)
then you would just need two small hoses that will connect to the water lines themselves and then attach the Y hook up the hose you fill your tank uyp with and your set and it should not cost to much .
I have thought about this alot actually because its basically the same system I put together for my 360 gallon tanks auto water changer
Hope this helps