Kanaplex contains an anti-biotic called Kanamycin. It can wipe out filters so monitor the water quality.
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If you have safe normal levels of chlorine in the tap water, it should all come out within 24 hours with vigorous aeration, longer with little or no aeration. If you have higher than normal safe levels of chlorine in the water, it can takes days or even a week to get it all out.
I think the safe level is 2ppm (mg/l)
If you have chloramine in the tap water, you need to add something to break the chlorine ammonia bond and neutralise the chlorine. Chloramine does not come out of water by itself and can only be removed/ neutralised with a dechlorinator.
Dechlorinators should not make any difference to medications.
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When treating fish with any medication, wipe the glass down, do a massive water change, complete gravel clean, and clean the filter before treatment and before re-treating the tank. This provides a cleaner environment with less gunk so the medication works on the sick fish instead of the micro-organisms in the gravel, filter and tank.
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I don't know what is in Esha2000 but if that and the salt seem to be helping, continue using it. Hopefully you won't need the Kanaplex.