Looks like .50 to me. While not instantly toxic to your fish, long term it is definitely not good for your fish. I am not an expert on RO or DI but I see a lot of folks on here that has them. I am fortunate my tap water is very clean. Thanks for your post, it has prompted me to research RO DI and their benefits. Hope all turns out well with minimal costs.
I'm colour blind so take this with a grain of salt, but I can't differentiate between the 0 and 0.25 swatches and your ammonia colour looks more like 0.5 to 1.0 to me so I would say it is almost definitely more that 0.25! You may want to use something that neutralizes ammonia before putting it in your tank. I haven't used it, but apparently prime will do so.
And if you do decide to use it, keep testing it in case it changes.
My well water would run anywhere from <10 to 40 ppm of nitrates and from 0-0.50 of ammonia. It all depends on what is washing off the fields around me and making it down through the ground to the well. It is also very acidic and hard.
So I went RO/DI.
Also, it’s been reported that the API ammonia test can be a bit inaccurate by about 0.25 ppm.
This probably sounds dumb, but fish produce ammonia anyways; won't established BB (after cycling) just convert the ammonia from the tap to nitrates the same way as the ammonia from fish waste? Can someone just explain what the negative impact of having ammonia & nitrates in tap water will be?
Yes you bacteria will just use it up. Ideally you don't want to add more ammonia to you tank since it converts to nitrates and we use water changes to reduce them. At your level I dought you would of ever noticed if you hadn't tested for it.