Why do we use DI on our RO systems.....

[Randy Holmes-Farley Verified Community Expert]

Ammonia also get

So I have dove into this topic and my local water and the water of Orlando where WWC gets their water from. Data baby!!! Orlando’s water contains 430% MORE copper (0.6 vs 0.14ppm) and 36% more lead than my tap. My tap water contains more hardness than Orlando’s (17 vs 7) so I will get more Ca and Mg in my RO water. Since I have to dose both Ca and Mg with my calcium reactor this shouldn’t matter. I am thinking about going straight RO!
@Randy Holmes-Farley if we assume 98% rejection rate I would be hovering around 2.8ppb. Thoughts on this level of copper?
Are there any other elements that we need to worry about besides Cu?

The water company cannot tell you how much copper you have at the tap. That is why the epa requires them to test at a bunch of homes to find out what the typical customers experience. Some folks will have far higher values than others based on your own pipes, how long the water sat in them, the temp and what the water company added to it that day, etc.

 

[Lousybreed]

Thanks for the input guys. I appreciate it. I have been talking with a lab, their professional statement was that ICP water testing doesn’t have the same resolution as lab grade tests. I don’t know if they are right or wrong. But they do test for copper “using EPA approved methods”. I was thinking about sending in pre and post RO to see if there is any thing to worry about.

 

[Midrats]

Be sure to let us fellow Wisconsinites the results.

 

[BuBBly FiSh]

Guys I have over 600 gallons in my system and I have a fair amount of dissolved CO2 in my water which rips through DI resin. I am asking if there is data about this. Not someone's feelings. Do we have data that DI is a must for reef success? I get that it is an added insurance policy. But is it needed?

I have high TDS water due to Calcium and Magnesium in my water, but I think we call all say that these two elements are not bad for your reef tank. Based on my water chemistry, 98% of my DI resin goes to removing Ca, Mg, and CO2.

What I fear is that needing DI is an urban legend. Maybe I send out my RO water and get it tested professionally (not ICP) and make my decisions based on that data.
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