Ok, this one has been bugging me, and I've tried researching what sodium thiosulfate, the main ingredient that de-chlorinates and breaks down the chloramines, actually does and if it is in fact harmful or not.
You can find the chemical formulae for what it does with chloramines, but little available research that indicates whether the resulting substances are that harmful or not. If you really read, the chemistry is very dependent on what else is in the water, the ph, the hardness, etc.... There are some ways the sulfur in sodium thiosulfate would ultimately leave the water by producing hydrogen sulfide (the rotten egg smell) or sulfur dioxide. Both are gasses, which means they would eventually leave the aquarium. Both are poisonous in high enough concentrations, but you aren't likely to see such high concentrations from dosing your aquarium water.
You can get salt in solution (the sodium from the sodium thiosulfate and the chlorine from the chloramine or raw chlorine if that is still used). But with a high carbonate hardness, you can end up with other stuff. If you have enough iron in your water and a deep enough substrate for the right kind of anaerobic bacteria, you can probably convert some of it into iron pyrate, or fools gold. Who knew?
Most of the scientific research I can find on this relates to water and wastewater treatment, so there's not going to be much funded research on turtle safety. I can find where there has been research on treating wastewater that has chloramines in it with sodium thiosulfate for release into streams/rivers. There is research showing that as safe for aquatic life. Of course, this is in an open system, not a closed system like an aquarium.
I did stumble across a few things that convinced me that a typical turtle keeper following the guidelines laid out here probably does not need water treatment. That statement sounds definitive. It's not. It's definitely opinion. I've had a turtle for a few months. I started out treating the water and after reading stuff here, stopped. The turtle is fine. I also suspect that any dangers of treating or not treating are going to be long term effects, not short term.
Before introducing some research heavy references, I want to mention a few things about how considering the safety of treating or not treating for turtles is very different from considering that question for fish.
If you are just dealing with chlorine in your water and not chloramines, the smartest thing to do is put your water in a container, throw in an airstone to encourage chlorine outgassing, and come back 24 hours later to your chlorine free water. You can easily avoid the entire issue of water additives.
Of course, if you have chloramines, like me, then you can't get rid of it by just waiting. That's why municipal treatment has moved to it: it hangs around.
Chloramines, like nitrite, are particularly deadly to fish. They both bind to hemoglobin more tightly than oxygen. This means that the gills exchange CO2 for the chloramine. The fish suffocates because there is little or no oxygen in its blood. It's basically the same thing that happens to us with carbon monoxide. Turtles don't breathe water. This is why any discussion of the dangers of chloramines for turtles is very different than the dangers for fish.
Turtles aren't breathing chloramines, but they are swallowing it. Of course, most of us are also swallowing chloramines. There's research to suggest an increased risk of cancer, but not an imminent danger of death. Chloramines probably aren't good for turtles, but they also aren't as dangerous as they would be for fish.
The real danger of chloramines for turtle keepers is killing off the bacteria in their biomedia.
Another thing that makes our tanks different than a typical fish aquarium is that we are overfiltered. We do not have too much filtration for the animal we keep, but we have considerably larger canister filters than a similarly sized fish aquarium. We also probably have sand instead of gravel, which provides a larger surface for bacteria to form on. If we're using carbon, like the recommendation here, we have more carbon and more biofiltration (via cansister media and sand) than the typical aquarium of the same size.
Chloramine is a chlorine atom bound to ammonia. Both sodium thiosulfate and activated carbon (more on that below) break that bond so you end up with a chlorine ion and ammonia in the water. Aquarium water treatments often have some other chemicals which make the ammonia less toxic by binding it to something else but still making it available for consumption by the nitrifying bacteria in the biomedia. The chlorine ion will ultimately either outgas as chlorine gas or be bound by the activated carbon in the filter. The ammonia will be dealt with by the bacteria in the biomedia.
So, one question is which is better/quicker at dealing with the chloramines: activated carbon or sodium thiosulfate. I'm pretty certain the answer is sodium thiosulfate. The reaction seems to be almost instantaneous. Activated carbon will definitely work, but it takes time.
I mentioned earlier that most of the scientific information comes from the water/wastewater treatment industry. An out of print 2004 book by the AWWA Research Foundation written by Gregory J. Kirmeyer titled
Optimizing Chloramine Treatment is partially available on Google Books. If I did that link right, it's to page 25, which talks about how activated carbon breaks down chloramines. Since I'm not certain the link will hold, here's the fair use excerpt from page 25:
(click for readable image if you have eyes like mine)
There are a couple of takeways from this. Activated carbon neutralizes chloramines as a catalyst. That means that it is a necessary step in the chemistry, but when done, the activated carbon is just like it was, meaning it can continue to act. However, it needs long contact time. Also, the first reaction results in ammonia, which is likely to be consumed by the nitrifying bacteria, so the second reaction may not have time to take place. And, the chlorine that results from the first and second reactions are bound to the activated carbon, which is one of the many reasons it needs to be replaced.
So, sodium thiosulfate can remove chloramines quickly, but leave other chemicals in the water. Activated carbon can also remove it without leaving sulfur compounds, but less quickly. Our turtles aren't nearly as affected as fish by chloramines, but that still leaves the bacteria in our biomedia.
If activated carbon alone can't remove all of the chloramines quickly, won't that kill our bacteria? I think the experience of many here shows it won't, but I also think I may have figured out why. In my research, I also stumbled across a 2009 PhD dissertation from Arizona State University by
Hyunyoung Jang titled ORGANIC CHLORAMINES FORMATION AND ITS DISINFECTION EFFICACY. This, again, is from the water treatment field.
Mr. Jang is looking at how effective chloramines are on killing bacteria. He even looked at some of the nitrifying bacteria that convert ammonia to nitrites. I've not read all of his 176 page dissertation, but I have read some of it. Specifically, he showed that chloramines can combine with organic molecules to form organic chloramines. These organic chloramines were not toxic to nitrifying bacteria and could be used by them to convert the chloramines to nitrates. He also showed that chloramine could be converted to organic chloramine in the presence of a biofilm--even a dead biofilm.
Remember, a turtle aquarium, with its oversized filter and sand, contains lots of biomedia to form a biofilm.
I suspect that turtle keepers need not use de-chlorinators to remove chloramines because our activated carbon does some of the work and our extensive biomedia takes care of the rest. Because our turtles aren't breathing the chloramines while this is happening, our turtles aren't suffering from the chloramines as the bacteria and carbon are dealing with it.
I could be completely wrong. I also think that the answer to the question of de-chlorinating additives is very different if you are keeping fish vs. a turtle.
However, in my mind, no de-chlorinator is probably the way to go since a de-chlorinator adds lots of chemicals that may or may not be dangerous and our typical setup, with more biomedia and carbon than a typical aquarium, will deal with chloramines without killing our biomedia or seriously harming our turtles.
I don't think you need to worry about your turtle dying from the chemical residue of a capful of de-chlorinator, but I don't think you need it either.
Posted: Fri Dec 07, 2012 12:29 am Water conditioner, do you really need it?
