# Why you shouldn't use tap water (Part 1)



## soulsigma (May 28, 2009)

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If you're thinking about setting up a marine aquarium you will no doubt be encountering no end of questions and plenty of decisions that need making. One of those questions may be, Can i use tap water in my tank? Hopefully reading on will answer that question for you...

What's so important about water then?

Marine fish have a reputation for being temperamental in comparison to other types of fish. The sea is the most stable Eco-system on the planet and is able to keep its water parameters perfect for the creatures that live there. Your tank will become a mini Eco-system of its own, so it is only fair to replicate the environment as closely as possible by using only the best quality water you can. After all, why spend hundreds if not thousands of pounds on setting up your tank, to use water which falls far short of the natural properties of sea water.

Natural Sea Water (NSW) contains hundreds of elements that are suspended throughout the water column and are essential to the well being of the animals that live there. Elements such as Iodine, Magnesium, Calcium, Iron, Strontium, Boron, Potassium etc. These levels rarely change by substantial amounts meaning these creatures are used to specific consistent water parameters day in day out.


What does tap water contain that's so bad? 

You may think that ordinary tap water is quite ok to use as we drink and bathe in it every day, but in reality you will find no end of un-desirables that, while not harmful to us in the doses that are present, they simply aren't suited to a reef tank.
When farmers grow crops they use fertiliser to help them grow. These fertilisers contain high concentrations of Nitrates and Phosphates, when it rains the fertiliser can get washed in to our local water supply. These are not removed because they're not harmful to us but in a reef tank they can be devastating. One of the constant battles for the reefer is removing these two unwanted organics, we certainly don't need to be adding them directly. 

Whilst the water is being piped through to your home its likely to pick up other elements from the pipes its travelling through as well such as copper, a metal which has catastrophic effects in a reef tank, fatal to invertebrates it kills anything living within an exoskeleton. The quality of your water will also vary dependant upon the time of the year meaning it would be very difficult to make consistent batches of saltwater for your water changes. 

All this means is that the fish, coral and inverts you're planning on keeping, put simply, are not used to having these unnecessarily added elements present. this means they're not good elements to be adding to your tank. For example ammonia, nitrites and nitrate are all toxic to marine life in varying degrees and most invertebrates are incredibly sensitive to copper. The tiniest amount in your tank is enough to kill them. Algae feeds on phosphates and nitrates, the higher these levels are, the worse your algae situation can be (see pictures) which has a knock on result and will make your PH levels unstable. 

The manufacturers of the major brand salt labels we commonly use, design the salt to be used with RO water. The reason they do this, is because our tap water supply is so inconsistent, it would be impossible for them to know how much of each of the trace elements to put in to the salt so that when we mix our water, the results would have the same properties as natural sea water. You would never be able to keep your water parameters stable, which is your No.1 objective really. This leads us to Reverse Osmosis......

This tank was setup with tap water. Note the algae covering the rocks as well as the sand.


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## Joey (May 27, 2009)

i have used tap water before all you need to know is what water treatmnent you have to give it when you use it but i dont recomend the use of it for a reef tank maby for a fish only tank


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## soulsigma (May 28, 2009)

*o2 Yes and so did I and constantly having to purchase chemicals to make it right was more of a chore to strike that balance for pristine water parameters which is a requirement for reef and marine tanks especially when you get into purchasing the $200+ animals.


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## AZDesertRat (Apr 10, 2009)

You are off to a good start here but you left out a lot of information and some that you did provide is not factual or entirely true.

The biggest reason to not use tap water is its inconsistency. It may be fine one day but a storm rolls through or a different plant operator comes on shift and its not the next. Even if its a groundwater or deep well system the particular wells or pumps that are running will all be different so the blend will be different. 

Nitrates are treated in plants, they have an EPA maximum contaminant level of 10 ppm but that level is above what most SPS corals can tolerate. Phosphates do not have an MCL though and is often added to distribution system piping as a corrosion inhibitor in the form or poly and ortho phosphates. Normally these levels are quite low but again not good for a reef system.

Saltwater fish can tolerate nitrates and phosphates at levels much higher than stony corals, I have seen successful fish only systems with nitrates exceeding 400 ppm and the fish thriving for years with no ill effects. Corals on the other hand would do poorly at those levels even soft corals like mushrooms, zoanthids and leathers.

The chemicals we can buy in the hobby that claim to remove all the contaminants really don't magically remove all them, in most cases they sequester or bind some of them chemically so they do not have the same effects. Nothing replaces RO or RO/DI water in this hobby when it comes to consistencey, owning your personal RO/DI system is a critical success factor in my mind and a cheap investment.


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## soulsigma (May 28, 2009)

AZDesertRat said:


> You are off to a good start here but you left out a lot of information and some that you did provide is not factual or entirely true.
> 
> Sorry but I am coming speaking from my own personal experience and the research that I did to correct my situation. I do realize that every tank is different and what might appears to work for some, may be a total disaster for another
> 
> ...




I agree with you and in order to ensure that no harmful contaminants or dissolved organic compounds are introduced into our aquariums, it is highly recommended that we purify our tap water with reverse osmosis (RO) unit for top-offs and prior to adding the synthetic salt mix, especially if you intend to set up a mini-reef.

*The bottom line is this: The water parameters in the world's oceans, especially in the areas around coral reefs, are remarkably stable in quality and chemical composition ( that is, if you discount the presence of the various pollutants introduced through human activeITIES.* OUR MAIN RESPONSIBILITY AS APIARIST IS TO REPLICATE THE CONDITIONS THAT MARINE FISH AND INVERTEBRATES HAVE ADAPTED IN THEIR NATURAL ENVIRONMENT AS CLOSELY AS POSSIBLE AND TO TAKE ALL NECESSARY STEPS TO PREVENT THEM FROM FLUCTUATING TO A SIGNIFICANT DEGREE.


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## AZDesertRat (Apr 10, 2009)

Yep.
An RO/DI system is always the first piece of equipment I recommend to anyone planning to get into this hobby. If you don't start out right to begin with you are setting yourself up for failure in the future. My current systems were all set up with RO/DI from day one, that includes curing the live rock and quarantining any inhabitants. I am anal when it comes to water quality so I own a Spectrapure MaxCap UHE system and maintain logbooks on the water quality and performance of the system.
I am not disputing what you said here only adding to it from a profesional water treatment plant operator and supervisors point of view. Thats been my profession for 34+ years. I will most certainly drink the tap water my plants produce but I still won't put it in my tanks.


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## soulsigma (May 28, 2009)

AZDesertRat said:


> Yep.
> An RO/DI system is always the first piece of equipment I recommend to anyone planning to get into this hobby. If you don't start out right to begin with you are setting yourself up for failure in the future. My current systems were all set up with RO/DI from day one, that includes curing the live rock and quarantining any inhabitants. I am anal when it comes to water quality so I own a Spectrapure MaxCap UHE system and maintain logbooks on the water quality and performance of the system.
> I am not disputing what you said here only adding to it from a profesional water treatment plant operator and supervisors point of view. *Thats been my profession for 34+ years. I will most certainly drink the tap water my plants produce but I still won't put it in my tanks.*




LOL*r2*r2*r2*r2*r2


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## tritonsgarden (Jun 10, 2009)

my biggest thing is that is that even though your tap water tested great.... is that they all have just a trace amount of heavy metals in them... and they will accumilate in your tank, heavy metals do not evaporate... you may not see a problem today but inside a year when your corals and fish are dying you will not figure it out......been there and done that!!!! RO/DI is the first thing I would buy even befor a tank!!!! just my opinion!!!!
KT


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## soulsigma (May 28, 2009)

tritonsgarden said:


> my biggest thing is that is that even though your tap water tested great.... is that they all have just a trace amount of heavy metals in them... and they will accumilate in your tank, heavy metals do not evaporate... you may not see a problem today but inside a year when your corals and fish are dying you will not figure it out......been there and done that!!!! RO/DI is the first thing I would buy even befor a tank!!!! just my opinion!!!!
> KT


The use of tap water, once chlorine and chloramines
have been removed should prove satisfactory for most
hobbyists. Sometimes, tap water may contain excessive
phosphates or nitrates or both for use in reef tanks or
with more delicate juvenile freshwater fish. Soft acid
water may also be contaminated with copper extracted
from pipes. In such situations, processed water may be
a good choice. If you wish to set up a soft water environment
for Discus or Tetras, and your tap water is very
alkaline and hard, processed water may be necessary. If
processed water is used in a freshwater aquarium it
may be advisable to replace some of the essential salts
that have been removed.


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