# Is tap water conditioner "safe"?



## BullDog (Apr 21, 2010)

I recently found this on another forum, and was wondering if it has ever been brought up here.
As I now understand it, most tap water conditioners use sodium thiosulfate to bind the chlorine, which apparently is not a good thing.
API has the Material Safety Data Sheet (MSDS) posted for their water conditioner on their site.
Tap Water Conditioner

MSDS:
http://cms.marsfishcare.com/files/msds/tap_water_conditioner_122309.pdf

Some key things that were pointed out from this MSDS are:
May cause respiratory irritation
Causes skin irritation
May cause allergic skin reaction
*Very toxic to aquatic life*
Causes skin irritation
Causes serious eye damage
Causes serious eye irritation

Now, I certainly don't claim to understand the MSDS, I'm more or less just passing on the observations of another.

But I was wondering if anyone here has looked into this?

The MSDS certainly indicates that sodium thiosulfate can be harmful, but in the concentrations that is in water conditioner, and if you follow the manufacture's direction, is it going to be harmful as it sounds?

Some googling reveals most saying sodium thiosulfate is safe for dechlorinating for fish tanks (and some have been using sodium thiosulfate to dechlorinate for 30+ years), with the occasional "The MSDS for sodium thiosulfate is scary!"

I know many like to let their water dechlorinate by letting it sit for 24 hours, or you can also run it through a filter with activated carbon.

Like I said, this was just brought to my attention from someone on another forum. I'm not saying anything about whether or not one should use a dechlorinator. I'm just wondering if anyone has more information on this?


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## Morainy (Apr 21, 2010)

Wow, I didn't know this and have never thought of it. So, it's probably not a good idea to "err on the side of caution" as I always do, and put in a little extra? 

Once or twice, I've caught my cat drinking out of the water change bucket. Do you think that dechlorinator would be harmful to cats?


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## BullDog (Apr 21, 2010)

I think unless your cat drinks a gallon of the dechlorinator undiluted, it should be alright, though don't quote me on it. I try to keep my cat away from both the clean and dirty fish water. 
For my turtle tanks, I usually use a little bit less than stated, but for my fish I think I add a bit extra too.


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