How do RO/DI systems work? RO/DI Unit should I get?

[arkodios]

I'm tired of waiting to start a reef. If I started months ago when I first got the urge, I would've already been months into establishing the tank. With BRS having sales right now, I think it's the perfect time to buy tank equipment. My issue is I do not know what RO/DI system to get. I don't want to buy one that is unnecessarily expensive if I don't need to, but I feel like my tap water has some issues that will need addressing. I get my water from the Boca Raton municipal water system. The water typically has 2.8 ppm of chloramine which often gives me a reading between 0.5-1 ppm of ammonia for my freshwater tanks. This is never really a problem because I am not doing large water changes and the added nitrate is not a problem. However, this seems like it will be a problem for a reef tank with corals. Unfortunately, standard RO/DI systems don't seem to do anything according to this BRS video:

My question is, then, what RO/DI system should I get? I was planning on a standard 4-stage value system from BRS but I do not think this will work out with the amount of ammonia in the water, and I believe the chloramine will exhaust the filters quickly. I'm also not really understanding what each stage in the RO/DI unit does. I know the point of the system is to remove all water hardness and other impurities, but I don't understand how each stage aims to do that.

 

[Protodad]

You can double check with BrS customer service but I believe you want a 5/6 stage one minimum to remove chloramines. The standard 4 stage will only work if your water is treated with chlorine.

LA water here and it’s heavy on chloramines but the 7 stage works great and gives 0 tds.

 

[KStatefan]

call Russ @Buckeye Hydro

 

[BroccoliFarmer]

My personal RO/DI method.