I decided a day or so ago to try the water change method before the meds.
mrakins: You made a good point about the pH being lower then what is being read, unfortunately I only have a reg pH test and a high range one.
I tried easy balance and even baking soda (NaHCO3, sodium bicarbonate) to get another reading. Im still puzzled by the pH drop, which is why I suspected the salt.
Ashdavid: Im kind of hesitant to use crushed coral as I do want to keep low pH fish such as rummy nose tetras and cardinals, and its the quarantine tank with the problem, so its not a huge issue as it would be if it was the larger tank. The larger tank has some co2 injected into it with a DIY setup. So I understand why the pH is lower in that, lol I haven't suffered through organic chem and the others without getting that much. Regarding the salt, when I say salt I meant more then the naCl as there are other stuff in it. Its the other stuff Im unsure of and I don't know what is in it, which is why I ask.
The pH of my tap is 7, and I do beleive I have a low Kh, as a month ago I got it tested and the petco employee said I had low Kh, I should've asked how low, but I didn't think they would know the answer. I've tried getting the numbers before and Im sure they try but they can't give me a straight answer.
The fish did suffer through an ammonia spike, with probably all the other stuff,(nitrite and nitrate), but I only tested for ammonia, and after I did it was enough for me to get the water changed. Eh it was a hectic time and I might've slipped that week or maybe something fell in, I had put it in the kitchen on the counter for the time being as we had just moved, and myself twice, (moved from college and the my permanent address changed), so Im sure he fish had had enough as well.
This wasn't the first time they've had it either, so after they get over this I plan on sterilizing the QT tank. Im not sure about the last bit about acids building up. I give it regular maintence and I've been changing the water, so Im not sure about that. But Im going to stop adding the salt and see if that changes anything and if not then go to the next hypothesis.
oh and I am using an AP master test kit
Thank you both for leaving helpful messages