Ro Water

[sparkey65]

How do you no when its time to replace the filters on a ro unit is there a test you can do? i already test for phosphate .but is there anything else?

[AttackDonut]

If you are filtering tap water, test your tap water for Silicates, Phosphates and Nitrates, then test your RO. If you start to see any..then it's time to replace.

[Dz99ls]

get a tds meter once they start to rise then change em!

[Randy Holmes-Farley]

Yes, I agree that conductivity is the easiest way.

This article has a discussion on that topic:

What is TDS?
http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.htm

from it:

"7. If you are using a TDS or conductivity meter to monitor the performance of an RO membrane, then the measured value should drop by at least a factor of 10 from the starting tap water. So, for example, if the tap water reads 231 ppm, then the RO water should be less than 23 ppm. In many cases, it will drop much more than that. Less of a drop than a factor of 10 indicates a problem with the RO membrane.

8. If you are using a TDS or conductivity meter to monitor the performance of an RO/DI system, then the measured value should drop to near zero. Maybe 0-1 ppm. Higher values indicate that something is not functioning properly, or that the DI resin is becoming saturated and needs replacement. However, that does not necessarily mean that 2 ppm water is not OK to use. But beware that it may begin to rise fairly sharply when the resin becomes saturated. Do not agonize over 1 ppm vs. zero ppm. While pure water has a TDS well below 1 ppm, uncertainties from carbon dioxide in the air (which gets into the water and ionizes to provide some conductivity) and the TDS meter itself may yield results of 1 or 2 ppm even from pure water. "

[sparkey65]

ok i reasd the article on TDS meters and they sound expensive and complicated. is there a inexpensive way to test tds? or can i just keep water testing for phosphate-silocates-and nitrates?

[Randy Holmes-Farley]

TDS meters are not especially complicated or expensive. A $50 TDS meter would be better than any kit for this purpose.

[Dz99ls]

we just purchase a tds from marine depot for 29

[chrisaggie]

TDS meter is very nice to have and almost a neccesity to have when testing a RO or RO/DI water filter. You can get them for under $30 if you look around.

[Unresistible Blue]

Be aware that the sediment filter and carbon block don't reduce dissolved solids, so if your looking to figure out when those cartridges need to be replced, a tds meter isn't the best answer.

If you're trying to monitor the performance of your RO membrane or your DI resin, then the tds meter is the way to go.

Blue

[sparkey65]

thanks everyone

[Dz99ls]

Originally posted by Unresistible Blue
Be aware that the sediment filter and carbon block don't reduce dissolved solids, so if your looking to figure out when those cartridges need to be replced, a tds meter isn't the best answer.

If you're trying to monitor the performance of your RO membrane or your DI resin, then the tds meter is the way to go.

Blue

very true but these filters just need to be replaced every 6-8 months

[gatohoser]

Sediment filters do not always need to be changed every 6-8 months. THe ones in my store last about 3 weeks due to about 80 gpd pure water being produced. Theyre cheap, depending on use id do it a little more often if you feel it deserves it.

[Dz99ls]

i referring to personal use not in a store what you say makes sense

[sparkey65]

are you on city water or a well?

[Dz99ls]

city water

[gtrestoration]

I use 80-110g per week of RO/DI and about 5g per week RO.
months listed reference change out times
• First chamber-10 micron sediment-1 month
• Second chamber - 1 micron sediment - 6 months
• Third chamber - .5 micron carbon block - 3 months
• Fourth chamber - RO - changed when rejection % drops to less than 90% or waste vs pure is noticeably different
• Fifth and Sixth Chambers - Color Change DI - As needed

TDS meter IMO is a must. As for the frequency of changing the sediment and carbon filters I'm not sure why I adopted the schedule. The first one a change more often because at one month it is very "orange".

Steve U