Uncle Sam,

If you had a TDS meter, you'd be able to determine this rather quickly, rather
than guessing. TDS is Total Dissolved Solids, and for our tanks, we want that
number as close to 0 as possible. Tap water ranges, anywhere from 100 to 550 or
more. Mine tested 171 TDS recently.

If you owned or could borrow a TDS meter, or take a water sample to your LFS and
ask them to use their TDS meter (they should have one on hand), it would give
you the results. The meter runs about $25 from MarineDepot.com and other online
vendors.

Your RO unit should produce water with 10 TDS or less.

Replacing your Sediment and Carbon filters every 6 months is a good habit to get
into. Looking at the sediment filter, it will look orange to rust-orange as it
traps all the big stuff before the water goes any further into your unit.
Originally, that filter is white.

The two carbon blocks trap and remove many other impurities, especially
chlorine. When you pull out the Carbon cartridge filter right next to the
Sediment, smell it. It should reak of Chlorine. The other carbon will probably
not have any odor to it at all.

Adding a DI to your system would remove the last of the TDS, getting you to 0.
(My RO comes out 2, and after the DI it is 0.) You can buy the extra DI setup
from Premium Aquatics for about $40 to $50, and it will be good for about 12
months. Then you'll need to replace the DI. How do you know when it is used
up? When the TDS of the water coming out of the DI is equal or higher than the
TDS of the water coming out of the RO membrane. If it is equal or higher, the
DI is spent and needs to be replaced.

I sell 2 Carbons and a Sediment on my site for $25 plus shipping. They are the
standard 10" cartridges. Scroll all the way down this page if you're interested:

http://www.melevsreef.com/ro_di.html

Marc




Uncle Sam wrote:

Sounds like there is no DI,, just a 3 stage, (pre, carbon and a membrane.)
DI
will remove silicates tha RO leaves behind. Diatoms fed on silicates.
A DI add on can be purchased for about $50

The filters say on the out side CARBON 1 CARBON 2 and SENTIMENT so
replacing the filters should do the trick?

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