Water conditioners in a reef tank  2/21/08
I have a question regarding water conditioners. I add Prime to my tap water when I perform water changes/top offs and I was recently told that water conditioners such as this will kill the pods in my tank. Is this true?
<That statement is a bit extreme, but generally speaking, tap water is bad for marine inverts.>
Would water conditioners have a negative impact on coral?
<If not the Prime, then the other things in the tap water, yes.>
So far I haven't observed anything bad happening. My usual top off method is to put a couple of drops in the bucket I'm using then filling it with water and adding it either directly to the tank or to the sump/refugium. Of course when I do water changes
I let the water sit for a few days to settle. Is it significantly better to use RO/DI water and avoid the water conditioners?
<The benefits of using RO/DI water go far beyond just avoiding water conditioners. Unless you live in rural Montana (or some other such odd place where the tap water is nearly pure), your tap water is loaded with stuff you don't want in your reef aquarium. Please see here:
http://www.wetwebmedia.com/watrqualmar.htm
And do a search on WWM for RO/DI and tap water filtration.>
Thanks, you guys are always a big help.
<De nada,
Sara M.>

Not so much of a question, but more of a warning. Tapwater use...    5/7/07
Hello Crew,
<Mike>
Just writing this in the hopes that you pass it on.  Previously, I subscribed to the theory that if tap water is safe for humans to drink, it is safe for the fish once properly treated.
<Mmm, you're learning...>
Yesterday, I did my normal 15% water change on my 300G FOWLR.  Prior to the water change, my readings were Ammonia 0, Nitrite 0, and Nitrate
<5ppm (API test kit).
About one hour after adding the new water, the tanks looked a bit cloudy, and the twelve fish in the tank (species not relevant to this letter), were acting "odd".  Difficult to describe odd, but you understand what I mean when your fish are just not acting like they normally do.
I tested the water again:  Ammonia 0, Nitrite 0.5ppm, Nitrate <5ppm.
To make a long story short, after checking all of my equipment and not finding any problems, I tested my tap water; the nitrite level was somewhere between 0.5 and 1.0 ppm straight out of the faucet.
<Yikes>
I added a bottle of "Cycle" to the tank to help the system along.
<Mmm, not a consistent/useful product unfortunately>
  the nitrite level was down to 0.25 ppm within 90 minutes and back down to 0 ppm by the next morning.
<Likely your nitrifiers effect>
So, my RO\DI unit should be arriving this week, and my water utility will be getting an angry call from me in the morning.
<Good luck t/here>
So, just a friendly reminder to the WWM readers, if you use tap water, make sure you spot check it from time to time!
<Good!>
Thanks again for this wonderful resource,
Mike
<Thank you for sharing Mike... You have saved many organisms, and many aquarist head- and heart-aches. Bob Fenner>

Chloramine Deaths.
Hi There,
<cheers!>
Recently, I've had deaths in my tanks directly after partial water changes that must have been chloramine-related. 
<Not likely... more commonly a discrepancy in temperature or pH. Do you really have so much Chloramine that you can smell it from feet away? Most dechlorinators easily neutralize this treatment>
I unfortunately used a "one-step" product for my water changes that I will never use again.
<do reconsider that most every Dechlor product is virtually identical in efficacy>
A friend told me about your site. I'm glad he did! I've did a good deal of reading of your site. I'm intrigued about your "vat method," -- letting water sit or be mixed for a week or more before being added.
<chlorine will dissipate in open air but chloramine never will... a chemical bond that must be broken (with a de-Ammoniating product.. most conditioners)>
My question is, what will this method do, if anything, to "toxic metals?" 
<absolutely nothing>
Should I be concerned about this?
<hmmm... rare in potable tap water. If concerned, get a prefilter stuffed with PolyFilter pads to draw water through>
Thanks! Walter B. Klockers Plano, TX
<best regards, Anthony Calfo>

Re: fish in dire need
Hi folks, I just sent Bob an e-mail, I think he must be traveling the world again this week.
<Just out in HI. Did you get my previous response?>
I have a serious problem that I cannot figure out. I live in the Twin Cities (Minnesota for those who are geographically challenged) I have 5 large systems that do not share water. I have friends that are all over the Twin Cities, Chicago and Milwaukee. ALL of us are having the same issue, in the past week we have all lost "rock solid" healthy fish in large numbers. I have done autopsies on 7 large fish and a Hybrid Clownfish I have had for 3 years. We all have some sort of Amyloodinium. My friend in Chicago has a very very high end set up, He has not lost a fish in 2 years- he lost 7 overnight. I lost angels, tangs, butterflies, clowns, Anthias, a Moorish Idol I had for 2 years, blue spot Jawfish, a red sea wrasse. Different tanks with very different systems throughout my house. We are desperately searching for answers. The symptoms are extremely heavy breathing for 5-6 hours, slightly clouded eyes, and within 24 hours the fish are dead. I started a Tetracycline dip for all the remaining fish, I have very large tanks so this is no small undertaking. I have kept fish for 20 + years and have never seen this happen. ANY SUGGESTIONS??????
<Sounds like something... like chloramine, alum... being "pulsed" (over-added) into the potable supply to counter a deficit in the concentration of sanitizer or in an attempt to whack a high TBC or even coliform bacteria count... I would enquire of your water co. (their number is on your bill) immediately and ALSO acquire a chloramine test kit pronto... and see how much stock dechloraminator it takes to knock the titer out. In the meanwhile, DO NOT change water in your systems if you can avoid it, and store any water to be used for a good week before any change. Bob Fenner>

Re: fish in dire need
Hi Bob, Ananda here with a request for clarification and more questions on this.
>> We all have some sort of Amyloodinium. My friend in Chicago has a very very
>> high end set up, He has not lost a fish in 2 years- he lost 7 overnight.  
Ack! Even in the far western 'burbs, my source water is from Lake Michigan.... I wonder if this person was using an RO/DI setup.
> <Sounds like something... like chloramine, alum... being "pulsed" (over-added) into the
> potable supply to counter a deficit in the concentration of sanitizer or in an attempt to
> whack a high TBC or even coliform bacteria count...  
TBC = total bacteria count?
<<Yes>>
Is this something that might survive a poorly-maintained grocery store type of RO unit?
<<No. Reverse osmosis units will exclude all bacteria>
They supposedly have UV sterilizers on them, but I doubt their effectiveness: I think the water flows by them too fast. Would one of those tap water purifiers help? A full-blown RO/DI system is not in the budget right now....
> In the meanwhile, DO NOT change water in your systems if you can avoid it,
How long is this sort of problem likely to last?
<<A few days. Bob F>>
Thanks,
Ananda