Doses Water Conditioner Accumulate in Tank?

[PCat]

I dose a bit heavily (3ml) with water conditioner during my 20 to 30% daily water changes (1ml per 2 gallons is recommended and I usually remove and add 4 to 5 ga). Cory from Aquarium Co-Op mentioned that one would need to dose 9 times the recommended dose before reaching toxic levels (I would never approach that amount). Anyway, does water conditioner accumulate in the water over time, or is it neutralized or gassed off?

 

[JuiceBox52]

It would accumulate if you add water with conditioner for top ups but never removed water. Have you considered 75% water changes weekly rather than 25% daily?

 

[Byron]

This question was raised in an earlier thread, so I will copy my response from there just to have it as part of this distinct thread. And in the interim, I have set the wheels in motion to find out!

That is a good question. It obviously does not remain effective, or we would not need to use it at every water change. And Seachem do state that the detoxification of ammonia/nitrite/nitrate by Prime is temporary, about 24-36 hours after which these three if still present revert back to the toxic form, so this is some sort of binding that is not permanent.

Using more than absolutely necessary is however harmful to fish.

First, like any additive, conditioner increases the TDS (total dissolved solids) and as these increase, the fish are negatively impacted (soft water fish more than harder water species). The TDS remain until we remove them via the next water change.

Second, like all additives, conditioner is pulled inside the fish via osmosis through every cell, and at the gills. It enters the bloodstream and is carried to the internal organs. Manufacturers saying this is not harmful is not being sensible; if harmful means the fish do not die within seconds, fine, but I have a much broader interpretation of "harmful." We need to use conditioner, but it should not be used at a level beyond what is essential. This is one of the main reasons I use and only recommend API's Tap Water Conditioner; it is the most concentrated product (1 drop per gallon, 1 ml treats 20 gallons) so less is used and therefore less gets inside the fish. It also contains no unnecessary additives to cause more trouble.

 

[AbbeysDad]

This is one of the main reasons I use and only recommend API's Tap Water Conditioner; it is the most concentrated product (1 drop per gallon, 1 ml treats 20 gallons) so less is used and therefore less gets inside the fish. It also contains no unnecessary additives to cause more trouble.

I'm not sure I follow. The fact that one dechlorinator is more concentrated than another doesn't mean that any less is absorbed by the fish through osmosis. You use less, but it's stronger - another product seemingly adds more [water] but it's weaker.
Dechlorinators probably breakdown to some extent, but regardless, like pollution, they can't build up as long as there are routine periodic water changes.
I do agree that manufacturer claims that a chemical is 'safe' up to many times the recommended dose is probably only 'safe' in that the fish won't go belly up right away so they can't be blamed. BUT of course, we're concerned with long term health and well being and to that desired result, we want to use as little additives as is possible to achieve the desired result. In fact, we'd be better off if we never used anything at all. I know, it's not possible, but it would be better!

 

[Byron]

I discussed this question of what happens to water conditioner over time with Neale Monks, a name that is (or should be) familiar to everyone in this hobby. Dr. Monks has degrees in biology and paleontology, has written probably hundreds of articles, and as the adage goes, whatever he doesn't know about the hobby is not worth knowing. The following is a summation of our discussion.

Conditioners neutralize chlorine/chloramine and heavy metals, and in both cases what it is doing is binding, hopefully irreversibly under normal conditions, to those chemicals. What is created is a new, soluble compound (or set of compounds) that stay dissolved in the water. Being non-toxic, they effectively become added to the total dissolved solids (TDS), but in such trivial quantities we don't have to worry about them. Sodium thiosulphate is the default dechlorinator, and reacts with chlorine to form sulphur, hydrogen chloride, and a salt called sodium sulphate. The sulphur isn't soluble and presumably precipitates out or else reacts with other chemicals in the water. But HCl and NaSO4 are very soluble, the first very acidic the second being neutral, but since both are in tiny, tiny amounts their impact on water chemistry will be nil.

I mentioned that Seachem have told me the effectiveness of Prime lasts 24-36 hours with respect to the heavy metals. Neale surmised that likely the EDTA used in Seachem Prime either breaks down or is metabolised by filter bacteria, so either way, can't be guaranteed to maintain the necessary concentration beyond 36 hours. But I don't know for sure.

As for what happens to the "conditioner," Neale said "nothing; it's just floating about, as new compounds or at least complexes, in the water. It does not likely dissipate out, or out-gas in some way. It would be removed as TDS at the next water change.

Substances dissolved in the water, like the conditioner, get inside the fish via osmosis if the substances are small enough particles to diffuse through the cell membranes. The fish's physiology will deal with it over time. Freshwater fish will be excreting a great deal of water because their cells are hypertonic to their environment (i.e., the water they are swimming in). Unwanted water-soluble chemicals will be excreted along with that water. While their kidneys are differently arranged to ours in some ways, their basic function and many of the tissues are essentially the same.