RO\DI Water

[philip huynh]

Hi All!
Can u guys let's me know what different between Drinking Water ( sell at Water store) and RO\DI water! And one more thing which one the best to refuel for reef tank when the water level in the sump goes down!Thanks

[Parrothead]

Hi All!
Can u guys let's me know what different between Drinking Water ( sell at Water store) and RO\DI water! And one more thing which one the best to refuel for reef tank when the water level in the sump goes down!Thanks

Coming from experience(recent) use ro/di water, if you can't get a unit of your own, get your water from your lfs, I've been fighting a hair algea problem for a while now, part of the problem is the drinking water is only ro at best, and if you use the drinking water machines keep in mind that is coming from the city water supply and again it is only ro, and I don't think they service them as we would our own units.......JMHO

[kevinpo]

Hello,
Water typically purchased from machines at the stores is connected to the municipal water supply. The water then runs through a sediment filter, carbon filter, reverse osmosis (RO) membrane, and sometimes another carbon filter. The end product has about 5-17 ppm of total dissolved solids (TDS). This water is quite acceptable to use for reef tank water changes and top off. However these units have lights that indicate when the filters need to be changed but the employees of the grocery stores don't change them themselves. They call a company to do it for them. There may be a delay and during that time the store continues to sell water. I have tested as high as 83 ppm TDS from one of these machines. The hobbyists version typically has a deionized (DI) resin cartridge after the RO filter which removes the last 3-5 ppm TDS from the RO filter. The resulting water has a TDS of zero. Using this water will guarantee that you will not be adding any nutrients for algae growth from your water supply and the mineral content will be only in the ratios of your salt mix (for water changes). I only use RO/DI water for my tanks.

Regards,
Kevin

[Parrothead]

Thanks Kevin,

I made the mistake of catching the machine 2+ weeks after servicing, my tank is finally starting to look normal again,

[philip huynh]

Thank guys!