Instant CHEAP pure 0 TDS Water!

[gbroadbridge]

I personally bought, on finance a Pure Reef RO $1500 400GPD Boosted 6 Stage RODI unit after my first year of using literal rain water mixed with a high quality salt-mix called Kirby's premium SPS sea salt to compensate.
Now I have total peace of mind with my water, I can make my own pretty much on demand, my reef system is only about 60 gallons so you could say it's overkill but I realized back then that I would want to upgrade one day, or even add multiple additional tanks so all in all, I'm happy with the investment.
The biggest con would be the RODI unit maintenance in paying around $450 for the kit to replace the units filtration. But the rate of which you do that is dependant on how much you use the unit so really, you're getting your worth out of what you buy when it comes to RODI units.
IMO it's kind of like buying an overkill Filter Roller. It might be more expensive and take up more room and cost more to maintain, but the rolls will also last longer, making you change them less giving you more time.

I paid $50 bucks for my 4 stage RODI 10 years ago from the local drinking water supplier, change carbon and resin only when needed at $10 a pop, never needed to change the membrane and get 0 tds water (calibrated device) and have a very happy tank.

The RODI water costs around 0.27 cents per litre to make using tap water.