Has anyone tried a long term experiment using tap water vs RODI water for a reef tank?

[Randy Holmes-Farley]

Would anyone be able to take a look at this tap water report that I was able to get from our board of water supply and tell me if it would be safe for me to use in my tank?

10% of taps have copper above 0.3 ppm, so I would not use it without your own copper test.

 

[Cycleguy0623]

The problem with city water reports is they can change when the city changes processes. Why risk your reef to an unknown.

Personally for all the money we put in a tank RODI is a small cost to know I have 0 TDS water to start with. I can account for everything in that water now based on what I add.

 

[ChrisPPolys]

Unfortunately I’ve lived in some of the least desirable places in Rhode Island (South Providence, Chad Brown, Pawtucket,Woonsocket) If you’re from the Area or surrounding states you know what I’m referring to….. I’ve also lived in the white mountains of Nh. As well as the south shore of Massachusetts.
All the while keeping and maintaining a thriving ecosystem. I have never used RODI water, using strictly tap water every place I go. Never running into any issues…

I could be entirely wrong, however the way I look at it is an immune system for corals/fish/inverts. I feel as if you only use RODI water they will become less tolerant of anything in your aquarium. Where as if using tap water they build up an immunity to all sorts of stuff.

All this technology has come about recently making people believe you need a degree in chemistry to keep a reef tank…. People are also under the assumption nano reefs are harder to keep and more susceptible to failure.
Without a calcium reactor, doser, sump, UV sterilizer, ATO or anything fancy. I have sucessfully kept and maintained Nano tanks for 12 years now. All I do is keep a 1 gallon jug of water that I fill up with tap water. Keeping an eye on my water level I try and add a half gallon at a time. With weekly or biweekly water changes, again, using tap water. I have never had any issues. <——just my two cents!

 

[Randy Holmes-Farley]

I could be entirely wrong, however the way I look at it is an immune system for corals/fish/inverts. I feel as if you only use RODI water they will become less tolerant of anything in your aquarium. Where as if using tap water they build up an immunity to all sorts of stuff.

FWIW, I don't believe that there is any evidence of any organism (land, sea, air) developing an immune resistance to heavy metal poisoning.

It is also not particularly useful to say you used tap water without issue when your tap water may be different in a very significant way than your next door neighbor on the same water supply due to copper from your own pipes. Lots of people eat raw fish. Does that mean all raw fish is Ok to eat?

10% of people in Woonsocket, RI have more than 72 ppb copper coming in their tap water. You were probably among the lucky 90%.

https://www.woonsocketri.org/sites/g/files/vyhlif5231/f/uploads/ccr2022.pdf

 

[reeferKen]

Northstar,
there are many examples of Tap water only in this thread. Take care. https://www.reef2reef.com/threads/how-many-of-you-is-not-using-rodi.789298/

 

[marinesnow]

Some have reported to use tap water exclusively, however tap water composition varies widely by locale, usually by county. Therefore, any positive results would not be wise to adopt.

Contrarily, one who taps their RODI water with the palm of their hand should be confident in using tapped water.