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View Full Version : Tap water quality, is it really that bad?


The_Alchemist
09/06/2006, 11:36 AM
Hi,

I've been keeping a 230 gal reef tank for over a year now, and haven't had any major problems..

I have been reading alot about people investing in ro/di systems to purify water, and while i'm considering investing in one, i'm not convinced that its worth it.

so far i haven't seemed to have any algae problems, and water pramaters aren't bad and so corals and fish seem to be well and happy.

I have heard that the water plant close to where i live is one of the most advanced in the country, and so given that fact is it still worth getting an ro/di unit when i aerate my tap water for 12 hours and add water conditioner (prime) prior to water changes?

here are some of the water parameters i obtained for the tapwater for my area.. does anyone know whether they are good or bad..

thanks in advance.


Test Typical value Unit
pH
90% of values between 7.5 and 8.5
pH units

Alkalinity (total)
35.8
mg/L as CaCO3

Colour (true)
2.38
Pt-Co units

Turbidity
0.47
NTU

Fluoride
0.91
mg/L

Total Hardness
39.6
mg/L as CaCO3

Iron
0.033
mg/L

Manganese
0.010
mg/L

Aluminium
0.033
mg/L

Copper
0.018
mg/L

Lead
0.0004
mg/L

(nitrates 0, ammonia and phosphates near 0)

drummereef
09/06/2006, 12:03 PM
Algae problems aren't neccessarily the only issue with tap water. There are many other metals and other properties of the water that make it not so great for aquariums. When you get to the DI stage it should basically be reading 0 tds. 0 total disolved solids. Pure. You can't go wrong with pure.

seattlerob
09/06/2006, 12:14 PM
While many of those readings look very low, it's my understanding that things like copper, lead, aluminum, etc will build up over time. So, even though you've been using tap water for over a year now, it's possible at some point in the future this 'build up' of metals will lead to trouble. And, it's likely you'll see the results but will be unsure of the cause.

The better test would be a TDS reading of your tap water. As drummerreef mentioned, RO/DI will give you very close to 0 tds. I just purchased the COM-100 TDS meter, and here are my results just to give you an idea of what RO/DI can do:

my tap water (seattle): 38ppm tds
after RO: 19ppm tds
after RO/DI: 0.6ppm tds

So, the RO water is 2x 'purer' than tap, and the RO/DI is 60+x 'purer'. Also, not sure where you're located, but I believe 38ppm out of the tap is pretty low compared to some parts of the country.

hth,
rob

RichConley
09/06/2006, 12:24 PM
seattlerob, why would they build up? Thats what water changes are for.



The issue with tap water isnt neccessarily the cleanliness. Its the lack of consistency. The water company flushes a main down the street, and suddenly you have rust, high ammonia, etc. You can go from the 35tds I had, to 500+ in a matter of a couple hours. It rains, and you get washoff in the resevoirs.



FWIW, there are plenty of heavy metals in our salt mixes.

RichConley
09/06/2006, 12:27 PM
SeattleRob, if you're only going from 38 to 19 through your RO membrane, either 1) Your TDS meter is bad, 2) your RO membrane is bad.


RO membranes should show between a 90 and 99% rejection rate.

So with TDS of 38 going out, you should get between 0 and 3 depending on your membrane. You should always get 0 out of the DI.


In my new apartment, I get 65 tds on the tap. I get about 2-3 coming out of the RO unit, and 0 coming out of the DI.


If 19 is going to your DI, you're going to be replacing it every 2-300 gallons, IIRC.

HowardW
09/06/2006, 01:08 PM
The TDS in our tap water here is over 350 and our water also contains chloramines, phosphates, silicates, and all kinds of other nasty stuff. I wouldn't even consider doing water changes or topping off with our tap water.

Some parts of the country however have very low TDS readings on their tap water, I heard one guy say his tap water TDS was 19

outy
09/06/2006, 02:19 PM
mine was 18 yesterday kind of stays around 21

i still have a ro/di and would not run without one.

scooters reef
09/06/2006, 02:30 PM
<a href=showthread.php?s=&postid=8089731#post8089731 target=_blank>Originally posted</a> by RichConley
seattlerob, why would they build up? Thats what water changes are for.


But tap water would also be added as top-off. The levels would slowly rise. A subsequent water change would drop them, but not all the way down to what was in the tap water itself because the concentration in the tank is already above that. Through time it would still build up. No clue how long until it was lethal to anything, but it would accumulate.

Paul B
09/06/2006, 03:47 PM
I used tap water in my reef for about the first twenty five years with no problem. Then the town put zinc orthophosphate in the water supply to control corrosion in the pipes. I lost most of my very old corals in a matter of hours. I had to buy 100 gallons of distilled water at a supermarket on Sunday night. Now I have a RO/DI
Although my tap water is fine, sometimes it changes.
Paul

cheeks69
09/06/2006, 04:04 PM
I have used tap water for 5 years with no problems at all. I have never tested it just add a conditioner and I'm done. I realize in most areas of the country the water quality is real bad and an RO is a must but for me tap it is !

Here's a couple of photos:

http://img.photobucket.com/albums/v292/cheeks69/150_5049.jpg

http://img.photobucket.com/albums/v292/cheeks69/150_5083.jpg

melev
09/06/2006, 04:04 PM
The metals aren't flushed out of the system via water changes, and often are trapped in the sandbed of your tank.

If your tank is healthy and happy, you may not need to change your system. Where I've lived, it was necessary to get an RO/DI for my tanks.

thor32766
09/06/2006, 05:19 PM
wow sweet tank, all i use is a carbon block drinking filter on my tanks

AZDesertRat
09/06/2006, 06:02 PM
Before even considering Tap Water I would suggest two things. Obtain a copy of your water utilities water quality report and study it closely. Next make it a point when you ask for the report to tell the person you are a salt water reef keeper and see if they will refer you to either one of their staff who also keeps fish or corals or to a plant supervisor or senior operator. Explain the same to them and listen to their recommendations. Ask how often they change sources or blends of water or change treatment techniques or chemicals. You might be surprised at how often your tap water changes in a weeks or months time. After storm events or seasonal changes water changes dramatically and thats a bad thing for tank stability.
I would never ever recommend tap water to a reefkeeper no matter what part ofthe world they are in simply because it does not have the stability that owning your own RO/DI unit has. You know each time you use it what the water quality is.
Things that are safe for human consumption and meet all state and federal regulations may not be safe for corals and things like metals do not go away but stay in your system and build up forever until your system crashes and leaves you scratching your head as to why.
Carbon does almost nothing for your tap water except adsorb chlorine and volatile organic chemicals and thats only if its a good one and is changed often.

BHF
09/06/2006, 06:39 PM
I dunno, hell, I'm a newbie, but I'll fall back on an well respected expert who states:

My view is that [pollutants in tap water] is actually insignificant compared with all the other contributing factors affectinging the makeup of your system's water...Compared with other contributing factors in marine systems, ordinary treated tap water is not typically a major source of concern in terms of added nutrients, pollutants, and/or metals...Marine Aquarists with reef systems and especially poor city or well water may find small home-scale reverse osmosis (RO) and deionization (DI) units of definite benefit, and more economical than the most basic catridge type conditioners. However, I suggest that even finicky reef types take a hard look at the quality of their skimmers and their feeding and supplementing habits before deciding that RO/DI will be their water-quality panacea. It's very often only a small part of the solution.

AZDesertRat
09/06/2006, 06:53 PM
Yes but ask that expert if they use a RO/DI and I would almost bet they say yes. My tap water TDS exceeds 700 all the time and can reach over 1000 ppm TDS at times. In the West and Southwest thats common and I sure don't want that in my reef system. I would have to agree with your expert though, water is the single largest component of a reef system and is the most important part of it so why not provide stability by using RO/DI. I have operated and supervised many treatment plants and water systems over the years and none has the stabiity day to day that a little inexpensive RO/DI unit has. Your expert may know corals and fish but he is a littl lacking on water quality knowledge if I may say so.

BHF
09/06/2006, 07:06 PM
::shrug::

I'm sure Bob Fenner has picked up enough here and there to get by. To each their own, but as Cheeks pretty clearly shows, you can do just fine with tap water.

AZDesertRat
09/06/2006, 07:08 PM
Bob is a personal friend and I can always disagree with him. It makes for some fun conversation. If you ever get the chance to spend some time with him I encourage you to do so, the guy is hilarious!

deadfish2
09/07/2006, 05:23 AM
I use the tap water filter and stress coat for my water. Everything fine and I got no alage for my snails. :)

seattlerob
09/07/2006, 08:09 AM
Rich: yeah, I think you're right. I just purchased both the RO/DI & TDS meter thru purelyh2o.com. The RO/DI is about 1 month old, the TDS meter I just received this week. I rechecked the RO/DI reading this morning and it was 0.3ppm. I will recheck the RO output again this afternoon.

Hoping neither my TDS meter or RO membrane is bad. But if I test the same, I'll circle back to purelyh2o.com & see what Bryan thinks.

Thanks,
Rob

<a href=showthread.php?s=&postid=8089750#post8089750 target=_blank>Originally posted</a> by RichConley
SeattleRob, if you're only going from 38 to 19 through your RO membrane, either 1) Your TDS meter is bad, 2) your RO membrane is bad.


RO membranes should show between a 90 and 99% rejection rate.

So with TDS of 38 going out, you should get between 0 and 3 depending on your membrane. You should always get 0 out of the DI.


In my new apartment, I get 65 tds on the tap. I get about 2-3 coming out of the RO unit, and 0 coming out of the DI.


If 19 is going to your DI, you're going to be replacing it every 2-300 gallons, IIRC.

RichConley
09/07/2006, 08:38 AM
<a href=showthread.php?s=&postid=8095513#post8095513 target=_blank>Originally posted</a> by seattlerob
Rich: yeah, I think you're right. I just purchased both the RO/DI & TDS meter thru purelyh2o.com. The RO/DI is about 1 month old, the TDS meter I just received this week. I rechecked the RO/DI reading this morning and it was 0.3ppm. I will recheck the RO output again this afternoon.

Hoping neither my TDS meter or RO membrane is bad. But if I test the same, I'll circle back to purelyh2o.com & see what Bryan thinks.

Thanks,
Rob

Rob, it may be seated incorrectly or something.

Were you just checking right after it started up? TDS can be much higher for the first gallon or two.

seattlerob
09/07/2006, 09:32 AM
Rich: when you say seated incorrectly, are you talking about the RO membrane? If so, I can check that. Honestly, when the unit arrived, I did not open any of the canisters to check anything. A couple were a bit loose & leaked, but I just hand tightened them until the leaks stopped.

I have a DI bypass and I was measuring TDS of the water com ing out of the bypass. In hind sight, I did not let the water run at all before taking the reading. I just filled up a tupperware with about 2 ounces & then took the reading. When I get home, I'll let it run & discard the 1st gallon or two & then take the reading. I'll bet you're right on the money & hope the TDS reading will be much lower. Either way, I'll post back my results & appreciate your comments :)

rob

AZDesertRat
09/07/2006, 09:51 AM
Use a very clean drinking water glass that has no dishwasher soap residue or any visible spotting on it for a sample container. Always triple rinse with DI water after each sample and again when you are done with it. Tupperware and other plastics can give bad readings.

seattlerob
09/07/2006, 09:53 AM
AZDesertRat: thanks for the advice! Appreciate it....learn something new everytime I come here :)

Rob

Tobman
09/07/2006, 09:56 AM
IMHO, really good RO/DI units don't cost that much (esp. compared to all else we spend) and are easy to use. It takes a bit longer to obtain the make up water, but you can do it while you sleep.

Just get an RO/DI unit and the question is moot.

RevHtree
09/07/2006, 10:06 AM
My tank has NEVER seen a drop of RO/DI water. It has been running for about 3 years now. My water is not that bad in my area though.

http://i6.photobucket.com/albums/y232/revhtree/tank2-1.jpg

http://i6.photobucket.com/albums/y232/revhtree/end.jpg

AZDesertRat
09/07/2006, 10:49 AM
Very nice tank! You are fortunate with your water as that is definitely not the norm.

CapnKick
09/07/2006, 10:54 AM
Nice tank Rev!

I posted the same question in a previous thread, and some very interesting points were brought about re: TDS. However, I agree that 1) water changes will remove accumulated solids and 2) there are so many other things to worry about.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=912332

RevHtree
09/07/2006, 11:02 AM
Thanks for the compliments.

Don't get me wrong here. I should have added that in most cases it is very necessary to use a purifying unit for your tanks water. I am going to get one anyway in the near future myself. Maybe I will have to do less glass scraping. :)

AZDesertRat
09/07/2006, 11:04 AM
CapnKick,
Waterchanges do not remove accumulated metals and inorganics. They bind with the sand and rock and are not removed. They are cumulative and just keep getting worse with time. Its best to not add them in the first place by using RO/DI.

CapnKick
09/07/2006, 11:11 AM
<a href=showthread.php?s=&postid=8096616#post8096616 target=_blank>Originally posted</a> by AZDesertRat
CapnKick,
Waterchanges do not remove accumulated metals and inorganics. They bind with the sand and rock and are not removed. They are cumulative and just keep getting worse with time. Its best to not add them in the first place by using RO/DI.

Please excuse my ignorance on this point. Do TDS include both organics and inorganics? Are we talking about everything in water other than H2O, or just the undissolved solids? Or does this include dissolved solids? I guess I'm confused as to what TDS are and how they affect our systems.

CapnKick
09/07/2006, 11:14 AM
And now that I read what I just wrote I realize how stupid that question is...clearly we're talking about total DISSOLVED solids. However, if anyone more fluent in chemistry can please explain the effects on marine systems it would be much appreciated. Also, are we talking about organic or inorganic?

AZDesertRat
09/07/2006, 11:46 AM
TDS can be both. Its really a poor measure of water quality as some constituents are not ionized either positively or negatively enough to read well with a TDS meter. Short of chemical analysis its the best we hvae for the hobby though.
Metals like copper which are present in most tap water up to a legal Maximum Contaminant Level of 1.3 mg/L are detrimental to a reef system. Remember EPA standards are set for human consumption not for saltwater reefs. Phosphates can be added to tap water for corrosion control and are another bad thing in a reef. Phosphates are very weakly ionized and even though they can be captured by DI resin they are also one of the first things it releases when it starts to reach exhaustion. Silicates are similar to phosphates. There are any number of things like this that are allowable in any and all municipal water systems in the US but are not good for your tank and its inhabitants.

CapnKick
09/07/2006, 12:07 PM
So I conjecture that the assumed behavior of these solids is that they eventually fall out of solution and bind with the substrate, rocks, tank and anything else they can bind to. Also, to the extent they remain dissolved, any buildup could be foreboding for algae control, diatom control, dinoflagellates, etc.

Assuming water changes can remove (and replenish without RO/DI, to some extent) the DISSOLVED solids, is there a risk from those that have binded to the interior components of the tank? Can they be leaching chemicals into the water column?

AZDesertRat
09/07/2006, 12:17 PM
We probably need to move this over to the Reef Chemistry forum and have Randy address this.

Nathan
09/07/2006, 12:26 PM
I have always had horrible quality water, so RO/DI is absolutely necessary for me. My city water is artesian well water.

Phosphates are so high the test turned inky blue.
Nitrates are high as well.
Lots of grit in the water as can be seen in my micron filter.

I will only ever use RO/DI water as long as I live with this city water.

CapnKick
09/07/2006, 12:34 PM
<a href=showthread.php?s=&postid=8097036#post8097036 target=_blank>Originally posted</a> by AZDesertRat
We probably need to move this over to the Reef Chemistry forum and have Randy address this.

Good call - I'm curious what Randy's standpoint would be on what happens to the TDS once in the system, how the buildup affects the system, etc. Do you know how to move the thread?

Randy Holmes-Farley
09/07/2006, 02:57 PM
Please excuse my ignorance on this point. Do TDS include both organics and inorganics? Are we talking about everything in water other than H2O, or just the undissolved solids? Or does this include dissolved solids? I guess I'm confused as to what TDS are and how they affect our systems.

A conductivity meter (reporting in TDS or other units) includes anything in the water that is charged, but in tap water that will almost entirely be comprised of inorganics, and most of the will be simple ions like sodium, chloride, calcium, etc. None of these are a concern for reef aquaria.

Some metals, like copper, and some anions (like phosphate) can also be a concern, and are why I do not recommend using tap water.


Copper and other metals will bind to organics and inorganics (like calcium carbonate) in a reef aquarium. Enough can stay in solution to be toxic in some cases.

These articles may be useful:


Tap Water in Reef Aquaria
http://www.advancedaquarist.com/issues/jan2004/chem.htm

What is TDS?
http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.php

AZDesertRat
09/07/2006, 03:28 PM
Thanks Randy!!!

CapnKick
09/07/2006, 03:30 PM
Yes, thanks Randy - that really clears up my curiosity.

seattlerob
09/07/2006, 05:28 PM
Rich & AZDesertRat: since curious minds have to know, I did retest my all my water for TDS. This time, I let the water run for a bit before I took the sample, and also used a clean glass instead of tupperware. These readings are from a HM COM-100 TDS meter:

tap: 35ppm
RO: 1.8ppm
RO/DI: 0.4-0.5ppm

Those numbers seem more inline with a good working RO/DI unit I guess!

Interestingly, when I sample RO/DI that's been sitting in a 10g rubbermaid container (white trash can), the TDS reading right now is 1.3ppm. So, AZ's note about plastics giving bad readings seems to hold true. I am guessing the really pure RO/DI is absorbing TDS from the container and/or air. Makes me wonder if I should be using a different container to store the water in, such as glass, and whether I should cover the container as well (currently I just leave it open, but it is inside a cabinet)...

AZDesertRat
09/07/2006, 06:35 PM
Much better numbers! I would cover or somehow seal the storage container though. I love my COM-100, nothing even comes close to its accuracy or sensitivity on the low end. Its nice to be able to test water down to about 10 megaOhms resistivity which is absolutely great water.

seattlerob
09/07/2006, 09:44 PM
AZ: truth be told, the fact I own a COM-100 is due your high recommendation I've read in several posts about RO/DI & TDS :)

As is so true with this hobby, I try to research as much as I can & hopefully make good choices along the way!

I'm sure I can find something to cover the water with. I remember thinking when I bought it that I wish it had a cover...oh well.

Rob

<a href=showthread.php?s=&postid=8099496#post8099496 target=_blank>Originally posted</a> by AZDesertRat
Much better numbers! I would cover or somehow seal the storage container though. I love my COM-100, nothing even comes close to its accuracy or sensitivity on the low end. Its nice to be able to test water down to about 10 megaOhms resistivity which is absolutely great water.

The_Alchemist
09/08/2006, 12:31 AM
Thank you to everyone for your replies... i'm learning alot and have attempted to call the water quality manager in our area but can't seem to get through..

I want to obtain a detailed report of the TDS and general water quality value's for this region and any possible fluctuations, and will make a judgement then as to whether i should invest in RO/DI..

For the mean time, thanks again.

The Alchemist.

CapnKick
09/08/2006, 08:42 AM
Mine are available online...where'd that link go...look in my post that I linked to above, I think it's the utility's website.

CapnKick
09/08/2006, 08:43 AM
sfwater.org