Sky High Ammonia, Barely Showing Nitrites, Nitrates

HI All
First time posting here.
I'm not a beginner, but didn't know where else to post my questions.
First, we live in a rural area and have well water. There is a spigot straight from the well in the basement. The house water goes through a filter, then a water softener, then to the taps. In the kitchen, there is also a RO unit.

My test kits are Nutrafin

Currently cycling a 45 gallon tank but this is about the 10 gallon tank.

It's been established, and stable, for at least 4 years now. There are 4 goldfish in it. Yes yes I know. I use the RO water for the tank without any additives. Yes, yes I now know that is not good either. Once in a the larger tank, I will be weaning them from RO to well water.

The Well Water has no ammonia and a pH of just over 7.0
The RO Water has no ammonia and a pH of just under 7.0

The 10 gallon tank has suddenly decided to spike the ammonia. And I mean Spike. On the Nutrafin test it shows waaaay over 6.1

I have not removed any of the filter media, or done a deep cleaning of the filter or gravel. There are no dead fish in the tank. I feed twice a day and just enough that it all gets eaten. I also add about 1/4 tsp of aquarium salt to 4 litre (1 gallon) Water Change.

Feb 7 - Ammonia - 6.1++++++; didn't check nitrites or nitrates
Feb 9 - Ammonia - 6.1+++++; Nitrite - 0.0; Nitrate - 0.0 PWC of 7 litres (just under 2 gallons); pH - between 5.5 and 6.0
Feb 11 - Ammonia - 6.1+++++; Nitrite - maybe just a hint of color (or my imagination); Nitrate - 50; pH - still between 5.5 and 6.0
Feb 12 - Ammonia - 6.1+++++; Nitrite - maybe just a hint of color again; Nitrate - still 50; pH - between 5.5 and 6.0

Normally I do a 25% WC every 7 - 10 days. I have not been doing 10% - 15% WC daily for almost a week without seeing any change in the ammonia level. Yesterday I did 2 15% WC.

My husband is picking up Seachem Prime today. Since I'm on a well, I'm not worried about chlorine, but I am very worried about the ammonia level. The kit I'm using is new, and shows differences in the 45 gallon tank that I'm fishless cycling. (I'm adding 5% pure ammonia to that tank and while I never saw nitrites, it is now showing nitrates and the ammonia spikes to around 3-4 when I add the ammonia but is 0.0 24 hours later.)

I have no idea what is causing the ammonia to be reading over the top of the chart. And I'm leary about doing too much WC because of the difference in the tank pH and the RO pH.

Any help and advise will be greaty appreciated.

And I now know that keeping goldfish in such a small tank is wrong, wrong, wrong. And I shouldnt be using straight RO Water. The fish are just common goldfish.

Thanks
Barb

 

sorry, can't see where to edit my post.

I have been doing partial WC for the last few days.

 

If the bigger tank is processing ammonia I would acclimate them to the bigger tank.

 

I haven't heard of a NutraFin test... I would try doing water changes very frequently until that number goes down, (i.e. 50-75% every day). I would try the first waterchange with one quarter well water, one half, etc. Or, you could try drip acclimating them to well water.

 

You have ammonia because you have 4 goldfish in a 10 Gallon. You should have 0 goldfish in a 10 Gallon.

45 is still much too small for 4 goldfish.