i personally have used tap water setting mine up. gotta dose it with dechlorinator, but it will work. i never ran in to algae issues other than the standard uglies that everyone gets, but that went away. on the other hand, tap water can vary. well water has different elements than city water, and cities will have different elements between them.
it can be used, but many people will say it is best to use RODI water because all of that gets removed through the filtration process. you can check your water departments readings. they are required to publish them. one thing you will find is that water contains trace elements of stuff that will scare even you, such as cancer causing things. if i recall right, my water department acknowledges that there is hexavalent chromium within it