Most cost effective option for water changes

[Ryan T.L.]

Hi everyone,

I have had my system up and running appx 7mos. It is 150g display w ~25 gallon sump and refugium. My question is what is the best/most cost effective way for me to be doing 25-30% water changes? Right now I am using tap water, prime, and instant ocean. When I change I change ~50+ gallons once a month. Local store sells RODI water .50/gallon or w salt for $1.50/gallon. I have not yet priced out an RODI system for my home. This started as a free to me "low budget" aquarium (recvd empty, dirty, w dead live rock and no fish)but there ain't nothing cheap about it.

Assuming you do 25% water change a month and pay those prices, you'd be spending between $18.75 and 56.25 at the LFS. The latter option is cost prohibitive IMO, even if you were to do a change once a month, and a waste. The former will pay for the cost of a decent RODI unit in 10-11 months assuming you end up changing DI and filters once. Given this hobby is all about the long haul and water quality is by far the most important thing I'd join the vote to get your own. Not to mention that the LFS may or may not maintain its equipment well etc.