is the Aquatic life ro buddie good to use in a reef tank
depends..
The one with the DI stage or not?
How many GPD does the one you are looking at do?
What is your incoming water TDS? <--important (get a TDS meter first to verify)
What is your incoming water pressure? <--important too (get a gauge to put on the hose bib to check)
How much water do you want to make?
Do you mind wasting more water than a "better" system? (ro buddie has what a 1:4.5 rejection rate which means for each gallon of "good" you dump 4.5 gallons of "bad" down the drain (or into a flower bed,etc..)
Do you want to drink the water too from a drinking faucet?
In reality a "good" RO/DI system is worth the extra money.. Check out the systems at bulkreefsupply or airwaterice or buckeye hydro or spectrapure and one other vendor of this site that I'm forgetting (sorry guys)..
Things that are good to look for (and almost can't live without)
#1-high rejection rate RO membrane (higher the better in general)
#2-Includes a dual TDS meter
#3-All full size (2.5" x 10") filter canisters including the di stage.
#4-ASOV (automatic shut off valve)
#5-Good carbon filters for chloramine removal (if your city uses it.. probably does now)
#6-pressurized tank if you want drinking water too