How did people get around it before R/O filters were readily available to normal people?
Truthfully this hobby has grown substantally in the last 10 years. Those that have been in the hobby for 10+ years can tell you this. Infact I have heard stories of very successful hobbists that when they started in the hobby back in the 80's or even early 90's there where many fish and corals that the experts consitered unsutiable for the home hobbists because the proper needs where still somewhat unknown or the technology was not economicly feasable. Over the last 5 years RO
units have become more and more economical as well.
If your not having algae problems or any other issues with using tap water then by all means you can continue to use tap water. Possible long term effects would be a buildup of heavy metals that are found in common tap water. How long this might tank will depend on your tap water makeup. Since each towns tapwater has unique properties its hard to say if you will have this issue in the future or when it might occur.
If your looking at a FO
setup then tapwater will be ok. If your looking into corals and other inverts then you could benifit more from RO
water. Some LFS
's will sell RO
water for $.75/gal
or something like that and many wal-marts will have water stations setup where you can get filtered water for as cheap as $.25/gal
. The only downside is that you have to transport the water around.
I like to look at the RO
unit as an investment vs an expense.