I finally bought one (RO/DI)

[steve5520]

And now I'd really appreciate some help. I've been reading the forum for a few weeks now and picked up some very helpful info.

I bought a 100gpd 6stage from Aquasafecanada on ebay. At the price, I figured I had to try it. Hopefully it's a good unit.

Now the questions, since I know nothing at all about RO/DI except that it will finally be clean water.

1. After filtering the water, do I need to add anything but salt?
What if I don't need to add salt, just using it for topoff water? If I add something, what's the best to use?

2. It may sound silly, but I assume that I will just "go to filtered water" through normal water changes. It will take some time before I actually have all filtered water in the tank.

I've had the tank (actually two, one reef, one fish only) for a while, but I've always just used tap water. I appreciate any advise that anyone can offer.

Thanks.

[Dewey]

That was one of the best this i bought was a good ro/di unit. I myself use the ro/di water for top offs and for water changes i dont ad any thing but salt. I have a 30 gallon rubermaid garbage can i use to store water in.

Hope this helps Dewey

[fishfreek]

This is how I describe it.

If you physically remove water from the system then you need to replace it with saltwater. If you are simply adding water to replentish from evaporation then you should add freshwater.

Some of us including myself use Kalkwasser in our water to help maintain calicum levels but you dont need to do this if you have a fish only setup or if your calicum load is not very heavy.

[steve5520]

Thanks.

I know this is the wrong place, but I forgot to ask about using RO/DI in freshwater tanks. If memory serves, I will need to add something before using in a freshwater tank. Or will the pH stabilize from what's already in the tank?

[Biggen]

Using RO/DI water in a FW environment is an all around bad idea. This is because one normally doesn't add anything to the water other than a dechlorinator (unlike SW where you add salt mix that contains all essential vitamins and nutrients). You would have to buy select products that would add everything back into the water that the filter is taking out. Also you are drastically lowering the water's pH (i.e. pH of 6) and taking out just about every amount of alkalinity in the water (i.e. low KH). This would lead to you having no buffering capacity, low water pH, and no minerals in the water for plants or fish.

Check with the FW guys if you want a more specific answer, but like I said, it is generally a bad idea.

[CountZero]

I bought My RO/DI unit from the same vendor, and I am totally happy with it. It works well, and I picked up a TDS meter and my total dissolved solids went from 246(out of the tap) to 4ppm. If you dont have a TDS meter I really reccommend you purchase one, its well worth the money to be able to know how well your filters are working and wether they need changing yet or not.
Zero

[steve5520]

I don't have one yet (TDS meter). I've been seriously considering getting the inline one from aquariumwaterfilters.com. Checks after RO and DI.

I was planning on getting a pressure gage too, as I don't see one on that unit for some reason. I don't have it yet, supposed to get here Wednesday.

[CountZero]

Get the handheld one unless you really want the inline version. It’s a little cheaper, and it also allows you to test your source water so you know the improvement over tap water. Plus, its really simple to use, and no need to install That’s the lazy in me talking.
Zero