Did I Contaminate My New 20G Tank?

[smitce01]

I bought a 5.5gal tank and put 3 fancy guppies in it.  The tank is heated and has HOB filter.  I only waited a week to add the guppies not realizing that I should have done a fishless cycle first.  It has been 3 weeks now.   I was checking the ammonia on a daily basis and doing 20-50% water changes every other day.  I went three days without a water change and the level got to .50.  The water was at about .25 ammonia quite frequently before that.  My ph is around 8.2.  I noticed that all three fish looked sick.  They looked pale and their scales looked like they were deteriorating. One looked like he had white spots or at least had something wrong with the scales.  Another one looked bloated and his scales looked very ragged and dull looking. I did a 75% water change.  The next morning the bloated looking one died.  I added some salt to the water because I read that can help treat ich, but I didn't know if it was ammonia poisoning or some kind of parasite.  I had the fish for 3 weeks so I would have thought they would have been sick by now if they had something when I bought them.  A week ago I bought a 20 gallon and started a fishless cycle with pure ammonia from Ace Hardware.  I moved a couple plastic plants from my 5.5gal into the 20gal not thinking much of it and the same day is when I realized my guppies were sick.  My questions are: Does that sound like ammonia poisoning?  Could it be some type of disease even though it took 3 weeks to show up and they all three got it at the same time? Did I contaminate my new tank which has begun to cycle?  Can I let the new tank set empty for a few weeks to kill off any parasites ( I am leaving it empty to cycle anyway).  Any advice would be helpful I don't know anyone that knows anything about tropical fish.  Thanks.

 

[Munroco]

I'm not certain if whitespot will die off if there are no hosts for it, but a good way to make sure is to raise the temperature to about 85, you can probably raise it more as there are no fish in there.

 

[smitce01]

I was thinking of doing something like that.  Do you think 85 is too high for completing the fishless cycle?  I don't want to ruin the bacteria or stall it.  Thanks. 

 

[Munroco]

I think 85 will certainly be ok, some tropicals are best at these temperatures and even higher so I'm assuming bacteria will survive too.
 
I remember an old ad on tv for some domestic cleaner talking about germs. "At high degrees of heat they die, if merely warm they multiply"