Mysterious Source Of Ammonia (tank Doesn't Even Have Fish In It). Can Anyone Help Me?

I am at a loss as to what is going on, this is happening in all of my tanks and I didn't realise because whenever I tested params and they were looking not so good I'd do water changes to get it right down back to less than <1ppm and throw in some prime to detoxify the rest. There was even conversion to nitrite and nitrate but the constant production of the mysterious ammonia is too much for the bacteria to consume at a fast enough rate.

I've moved my goldfish into a ~50 gallon plastic tub (cleaned thoroughly first of course, gravel also rinsed thoroughly) and my betta fish into a 5 gallon tub (same procedure). I've tested ammonia/nitrite/nitrate over the last 2-3 days and everything is 0ppm according to the API test kit. I have still being adding prime at the recommended dose in both.

Sorry if the plastic tub is cruel, its the only thing I can think of so as not to expose them to such high levels of ammonia/nitrite.. they are both very sick but are seemingly improving now that they are in the tubs.

Both tubs have heaters but I was hesitant to put the filters in because I have a suspicion the ammonia is coming from the filter media, is this possible?

Also, I did an experiment where I left my betta's tank (without the betta in it) with 100% water change and no filter running over night and there was a lot of ammonia in there, the test kit definitely went a medium to dark shade of green (can't remember ppm exactly), there was about 2ppm nitrite in there as well.

In one of the tanks ~25 gallon the ammonia was >8ppm after only 2 hours (had done 100% water change prior), this had one goldfish in it at the time.. this was when I realised what I had been doing to my poor fish (yes, I feel awful, this is my first time having fish and I regret making such a horrible mistake), this is what prompted me to get the huge plastic tubs as I had deduced it was the tank/filter that was the problem.

I've tested my tap water as well to see if that is the case and it is ~0.2ppm (hard to tell with the test kit because in different light it looks a little different). I've also added a drop of prime to the tap water and tested it to see if the prime was giving false readings and nup, same result.

Any help would be greatly appreciated. I feel terrible for what I have put my fish through, I tried so hard to do everything right.. I did so much research after I bought them (I wish I'd researched before otherwise I would have done a fishless cycle before purchasing).

If someone could explain to me what is going, what I did wrong for things to get so bad, how to fix this problem with the tanks/filters and how I can prevent this in future I would be so grateful (and my little babies will be too if they are able to tough this out fingers crossed)

(I also gravel vacuum every time I do water changes and I have been doing them whenever needed to get the params back to normal, I really wish I had done a fishless cycle.. I know it is my responsibility to do research but I asked the pet store a lot of questions and they mentioned nothing about cycling/bio filtration... if they had I would have just bought the tank and cycled it first... I feel like they don't tell people because they honestly don't care about the fish and if customers fish keep dying it means their sales increase..... so much cruelty)

 

so I do have questions but in terms of solutions do you have any friend, family or nice person at your local fish shop who would give you some established/ cycled media?

 

It sounds like the amount of ammonia in your tap water has built up in your tank. Have you tried treating any new water you add to the tank with prime?

 

Have you been cleaning your filters in tank water and not letting them dry out, or leave them in the air for more than half a minute? Tap water or letting them dry out will kill the bacteria in the filters, but they do need to be cleaned in water from your tanks (Water from before a change!). I also had a similar problem and it turned out my catfish had been hoarding food underneath a cave. Do you check your ornaments for food build ups? They do need to be shifted during cleaning. I just did my own betta tank and the worst of the gravel buildup was underneath an unmoving driftwood log.

 

I had been cleaning my filters in tank water, but I think I solved the problem. My filter must have been contaminated with something that was actually producing ammonia because when I put a new sponge filter in the ammonia levels stopped rising.

I then added a drop of ammonia and a fair bit of API quick start to see if I can get the biofilter up and running. It's been about 2 hours and the ammonia level has reduced based on the test.

Once I can confirm the ammonia is NOT rising, I will do a water change and put my betta back in his home.

From this day forward I will be checking params twice a day.