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.

 

[MnFish1]

Yeah, I haven't looked into corals and copper toxicity much, but I have looked into inverts and copper toxicity a bit and 0.02 mg/L seems about right (for the first quote below, the water quality report was for Oceanside, California, and the numbers used were mg/L):

Interesting - and a question for @Randy Holmes-Farley - So - do you know of any studies of whether small amounts of Copper (for example if used in tap water for top offs only) can be incorporated into crustaceans, etc in the tank? Obviously if the level just kept going up with every top-off that will be a problem if it does not dissipate. I have seen multiple copper recommendations - and vis a vis coral I believe there is some variation in toxicity levels.

 

[MnFish1]

The TDS for the tap water in my town is ~60 which is great for tap water so I thought “why not” and that’s how I filled my first reef tank. I’ve been using treated tap for a long time with fresh water tanks and I have ultra clear water and an almost self maintaining tank.

Enter the reef tank and ugh… lesson in humility. The amount of hair algae was just insane. While some LPS did really well, gonis for some odd reason did awesome in that tank, others did not… torches would wither away. Duncans loved it. Acans did well. My red fire Digi did okay. The rest of anything SPS that I tested would usually be okay for a day or two and then STN would kick in. The phosphates were always at 5 (yes 5, not 0.5) or above and the nitrates were 20-60. Stability was nonexistent.

The only difference between how I run my current system versus how I ran my previous system: you guessed it RODI instead of tap. I guess I also carbon dose now which I did not do from the beginning with my previous tank.

Just my experience. I am sure some tap water out there can support a reef tank without causing issues, but I also know that few sources are likely to.

Curious, what was the phosphate and nitrate in your non-filtered tap water (when adding to the tank).

 

[MnFish1]

If there is lead present but at a level deemed safe for drinking, I can’t imagine it would have a detrimental impact on your aquarium unless you have the system for decades and decades and could achieve some actual bioaccumulation. There is some copper present, but the highest recorded value was 0.065mg/L…meaning all other tests were below that. That is not a particularly alarming number.

To me this doesn't follow (I may be misreading) - aren't there a lot of chemicals whose levels are less than what may be toxic to humans that are toxic to fish/inverts? Like Chlorine. The usual copper level in drinking water is a higher than the one you're using - but the bottom line (I think) would be whether the copper is removed by something you're filtering with - otherwise there is a chance for accumulation over time. Hopefully I was not misreading your meaning!!

 

[crazyfishmom]

Curious, what was the phosphate and nitrate in your non-filtered tap water (when adding to the tank).

Nitrates were around 3 ppm. Phosphate was around 1-2 by salifert. Silicates were also high but I don’t remember how high.

 

[Randy Holmes-Farley]

Interesting - and a question for @Randy Holmes-Farley - So - do you know of any studies of whether small amounts of Copper (for example if used in tap water for top offs only) can be incorporated into crustaceans, etc in the tank? Obviously if the level just kept going up with every top-off that will be a problem if it does not dissipate. I have seen multiple copper recommendations - and vis a vis coral I believe there is some variation in toxicity levels.

Copper has many sinks in a reef tank, including organisms. It will decline if never added, but fish foods contain it.

 

[Randy Holmes-Farley]

To me this doesn't follow (I may be misreading) - aren't there a lot of chemicals whose levels are less than what may be toxic to humans that are toxic to fish/inverts? Like Chlorine. The usual copper level in drinking water is a higher than the one you're using - but the bottom line (I think) would be whether the copper is removed by something you're filtering with - otherwise there is a chance for accumulation over time. Hopefully I was not misreading your meaning!!

Copper is an example. EPA allowed copper in drinking water is toxic to marine inverts.

 

[MnFish1]

Copper has many sinks in a reef tank, including organisms. It will decline if never added, but fish foods contain it.

Thanks - thats what I assumed

 

[GARRIGA]

To me this doesn't follow (I may be misreading) - aren't there a lot of chemicals whose levels are less than what may be toxic to humans that are toxic to fish/inverts? Like Chlorine. The usual copper level in drinking water is a higher than the one you're using - but the bottom line (I think) would be whether the copper is removed by something you're filtering with - otherwise there is a chance for accumulation over time. Hopefully I was not misreading your meaning!!

Macroalgae remove copper. Plants need it for chlorophyll production, for example. At the same time, excess can be lethal. Has been used as a treatment for algae removal. As with anything. Degrees matter. Water for our existence is crucial yet we can drown in it.

One experiment I ran was running tap as top off. My thought process being the GHA and Pom Pom macroalgae would remove many contaminants. ICP-OES showed 3 ppb after replacing 2g weekly for four months plus in 16g tank volume. Oddly my tap analysis didn't show any which would suggest it's too low to test in my tap or just none at the time of testing. House is new with no copper pipes and just assumed it would be leached somewhere along it's path from my water processing plant.

On a side note. Having algae might be a good thing yet I suspect that to some extent. The zooxanthellae might also be utilizing it. Copper is naturally found in SW yet somehow kept in check. Latter being pure speculation.

 

[GARRIGA]

Here's my results from testing tap as replacement. Goal was to see if algae would reduce some of it. Not my wheelhouse therefore another might be able to interpret this. All I cared about was getting it below critical levels although perhaps with a larger Fuge that might have been accomplished. Next round perhaps.

 

[Randy Holmes-Farley]

Here's my results from testing tap as replacement. Goal was to see if algae would reduce some of it. Not my wheelhouse therefore another might be able to interpret this. All I cared about was getting it below critical levels although perhaps with a larger Fuge that might have been accomplished. Next round perhaps.

What exactly is that icp result for?

 

[ca1ore]

Yes, it was called the 90's

Exactly what I was going to say …… 80’s as well for the fogie-fied amongst us.

Hard to isolate the effect that non RODI would have had as too many variables have changed. My guess is that the effects of using tap would depend upon your tap ….. and on the animals you choose to keep. So, softies less problematic than SPS.

 

[GARRIGA]

What exactly is that icp result for?

My test 20H that’s been running without water changes since September 2021. I’ve thrown everything including the kitchen sink at it.

 

[Lasse]

Here's some actual data for what I consider to possibly be the most serious problem with tap water: copper.

I´m think your right but IME old copper pipes may be better than new probably because of surface oxidation. I use my tap water for many years without any problems but in june 2020 - I got a lot of my CUC dying in an aquaria where I only use tap water. I know that they had done some pipework just before. I send in a water test for ICP analyse (tap water) and it contain around 41,6 μg/l copper. I know that it was caused by the pipes in our house because we did a tap water analys of the citys fire hydrant outside the public aquarium (only plastic tubes from the drink water plant to that fire hydrant) in 2021 and it was excellent to use for filling the 400 000 L tank.

Sincerely Lasse

 

[Randy Holmes-Farley]

My test 20H that’s been running without water changes since September 2021. I’ve thrown everything including the kitchen sink at it.

Some trace metals do seem quite high.