sounds like you shouldn't have any problems. but yeah, it's always a good idea to play it safe and not put non-purified water in the reef, or in with stuff that will eventually go into the reef. might suggest keeping the water warm too.
i may be off base with this, but it's fair to assume that all the critters that are living in our LR, being from the tropics, are not going to be too terribly cold tolerant. it may prevent a mass die off due to water being too cold.
just a thought though.