Toxins in Aquarium?

Question

I recently got a new 55g off of craigslist. I washed it out using warm water to get all the dust out of it. I filled it with pond gravel and sand. I filled the tank with water, added some Flourish and loaded the tank with different types of plants (water wisteria, java fern, Moneywort, amazon sword) There is 2w per gallon. Within 3 days everything was dead. All the plants became mushy but they all kept their color.

I am guessing I have some form of toxin in my tank but I don't know what it could be. The guy who sold me the tank said he did not use any cleaner on it, but he could be lying. How can I test for different toxins without having to throw everything away and start over ?

So far I have replaced the water a few times over and I have added tons of de-cholorinator in case he used bleach in the tank. I am probably going to try the plants again to see if the problem has been solved.

Answer 1

the problem is u make the mistake of putting a lot of plants very recently,some of those plants have different requirements,follow the directions carefully,tons of dechlorinator not a wise choice.

Answer 2

The chloramine in your tap water killed the plants. It's also possible that you introduced some sort of plant pest or herbicide if you collected the "pond gravel and sand" from the "wild". Still to kill the plants that quikly it would almost have to be the tap water. I don't think that  "Flourish" contains a de-chlorinating agent. Also since most de-chlorinating agents contain sodium (Sodium Thiophosphate) they should be used sparingly.

Your best course of action would be to drain the water and by a good plant book, and learn about cycling a tank,and start all over.

Those plants have different light requirements; and temperature requirements are also very important for plants. You have a lot of interesting reading to do.