How long ago did you replace the seal and what type of silicone did you use?

You're absolutely right
Sorry for coming across the wrong way

I only meant to point out that, once they get things under control, they should read up on how to properly deal with things

Good point Steve ....
I missed this completely

Did you move the sand over?

I would recommend Stability help stabalize the bacterias, and AmQuel Plus for the Ammonia (we actually tested prime & AmQuel, and found AmQuel much superior for removing Ammonia Nitrates Nitrites Chlorine & Chloramines)

Silicone can be the issue also, depending if it was mildew resistant

+ 1 on the ammonia, get some amquel, but don't overdose it.
+ 1 on the silicone as well, all GE silicone has anti fungal and algaecide except the GE silicone adhesive.

Depending on the silicone used and its chemistry, it could actually be producing ammonia as it is curing. That and GE silicones contain petroleum distillates for mildew resistance (though many of their products don't advertise this). If you're not already running a skimmer, do so as aeration is the only way to remove distillates if there are some.

+1000 on bacteria stability. MB7 is great to get the bacteria going again. Take it slow though.

side note, I would try to remove all the fish from the tank and then turn ur heat up to speed up the ick life cycle. If you turn heat up but still have fish in it, it just basicly increase the amount of ick inside the tank as long as there is still available host.

First 2 Things that crossed my mind +1 and +1 -- I'm going to say its either one of these. GE or Sand gas off.