I have read a bunch of different opinions on the use of
RO/
DI water for tank use and how necessary or advisable it is. First off how are you planning to set up your tank?
FO? or with inverts and corals? If the last, then the advice seems to lean towards a stronger case for filtered water. Other learned opinions from well respected authors in the field suggest that of all the things that can cause a problem in your tank setup, the criticality of using
RO/
DI water is the least of them. This author suggests that as long as tap water is dechlorinted and allowed to sit for a couple of days, any harmful elements percolate out of the water and it is okay to use in your tank. However, if you wanted total peace of mind (like I did) you may want to consider using the
RO/
DI water so that is never a concern. Just be aware that it is not considered an absolute for setting up your tank. There are some nice units available for under $200 that include a faucet hookup (I got rid of my PUR faucet filter - darn thing was clogging up too fast) so I can use
RO water which is stored in the included 4G storage tank. For tank use, there is the additional
DI treatment which removes all negatively and positively charged ions. Essentially pure H2O at the output end. The units are rated in gallons per day output. Just be sure to get a minimum 3 stage unit for the best filtration, plus the
DI treatment if so desired.
HTH 8)