eSHa as a company doesn't believe in dechlorinators so they say we shouldn't use them. On their website they say that dechlorinators remove chlorine and heavy metals but that there should be no heavy metals in drinking water and that all you need to do for chlorine is let it gas off. This does not get around the fact that snails and shrimps are affected by metals at much lower concentrations than fish, and at the levels safe for human consumption; and that lots of places use chloramines rather than chlorine which doesn't gas off. Besides which, I would have to leave rather a lot of water standing round to allow chlorine gas off and I don't think my husband would be very happy about that.
The website also says
Under normal circumstances and dosages water conditioners cause no problems. However when used excessively, because of their strong binding capacities, water conditioners (de-chlorinators, heavy metal binders, etc.) can potentially decrease the effectiveness of products such as disease treatments, algae / snail treatments, etc. or even give rise to reactions.
The red text is my highlighting.
So provided you use your dechlorinator at the dose rate on the bottle for just the amount of new water added at a water change, using dechlorinator is fine.
The reason it says to remove the carbon in a filter is that carbon adsorbs medication, removing it from the water. But you only need to remove the carbon, unless of course all that's in the filter is a carbon cartridge. And if the carbon has been in there for over a month it will be full anyway. Yes there is a slight chance that the medication will be more strongly attracted by the carbon and it could push off the the less attracted other stuff already there, but this is quite small. If a carbon cartridge is the only medium and it is not changed regularly, leave it there. if there is something else in the filter besides carbon, remove it and replace it with something else - you don't need carbon anyway.
And the filter should always be running 24/7 with or without medication.
eSHa 2000 is safe for all fish. It does not name any species that could have adverse reactions. Some medications do name certain species, for example a lot of whitespot medications say to use at half dose with scale-less fish such as loaches. Since 2000 does not name any species, it is safe with all fish.
eSHa does list the products not safe with snails and 2000 is one of those. Yes, remove the snails. They will be fine in the bucket, their metabolism will just slow down. I've done this with my nerite snails when I've had to treat the fish. Make sure the bucket is covered as nerites can and will climb out. Even an old towel will keep them in. Because there is no filter in there, change the water a couple of times a day and keep the bucket in the warmest room you have.
You will need to remove every trace of the medication before putting the snails back. It will take a lot longer than three days before you can put them back, I'm afraid.
Ways to remove the med are:
Lots and lots of water changes
Carbon in the filter, preferably several small batches rather than one big one. And throw the carbon away afterwards.
After using carbon I use a piece of
Poly-Filter. This is not filter wool/ filter floss but a special, very expensive, medium for removing all sorts of things including medications. Because it is expensive I use it as the final stage after the water changes and carbon have removed the vast majority.
However, just removing the med from the water does not seem to be enough. I have killed nerites by putting them back too soon. I have begun to think that meds are absorbed by algae, and when the snails eat this algae they get poisoned.
I would leave the snails in the bucket for at least a month. And if you have more than one, don't put them all back together. Just one at first.
This applies to virtually all medications not just eSHa 2000.
