I have read countless threads on discussion forums asking for assistance with water quality issues. Considering how many forums are available to hobbyists everywhere, it wouldn’t be difficult to imagine that hundreds of queries are posted on a daily basis just in the United States. With the availability of search engines, the information is readily available having been answered time and time again. Why is it so hard to master this particular area of our hobby? Are our personal circumstances so uniquely different from everyone else’s?
Hooking up an RO or RO/DI system directly to your sump is a recipe for disaster. Avoid this costly mistake.
When it comes to reefkeeping, there are numerous basic tasks we'd like to automate. One of the most desired features is a way to top-off the tank automatically in order to replace water that has evaporated from the system, and many beginning hobbyists may not consider how important this is. As water evaporates, salinity rises in the display tank because salt does not evaporate. The water simply becomes more and more saline the longer the hobbyist waits to add freshwater.
Topping off around the clock is the best way to keep salinity stable, and doing so from a reservoir avoids any risk of excessive additions of RO water.
The ATO reservoir measures 22" x 15.5" x 32" and is made with 3/8" cast acrylic. The only opening is a sliding access door at the top corner, just above a float valve. The container holds RO/Di water and I am very careful not to let anything pollute the water since cleaning it out would be extremely challenging. The 150gpd Boosted RO/DI system feeds water directly into the reservoir so I never have to lift a jug of water ever.
Using a 150gpd system provides 6.25 gallons per hour. After MACNA 2012, I had a 300gpd system on hand and decided to use it as well. Running the two systems side by side speeds up water production significantly, at a rate approaching 19 gallons per hour. I ran it like this for about a year or so, then reverted back to a single 150gpd system. Eventually, I decided to change out the membrane for a 100gpd instead due to the better 98% rejection rating which helped waste less DI resin over time.