OK. Sorry for so many questions, but the parameters are closely connected and can be influenced by several factors. You should find out about the softener, I am thinking that Florida might have hard water and your house might have a softener...just something to check as it ipacts fish.
Assuming not, for the explanation. In any aquarium the organic matter and dissolved organics produce CO2, which in turn produces carbonic acid, and the pH naturally lowers. The almond leaf is obviously one organic, but there are many others. Feeding the fish obviously. The pH thus naturally tends to lower, which is where the GH and KH come into play. These can affect this, especially if they are substantial. Here they are not, so there is no buffering capacity, or very little, on the pH.
This is not really a problem. Bettas are soft water fish, and they come from and prefer soft to very soft water with an acidic pH. The Betta will be fine. If you had hard water species, that would be a very different matter.
Do regular (once a week) partial water changes, change half or a bit over of the tank water at each, use the conditioner but nothing else. This will work to buffer it somewhat. The almond leaf is still beneficial to the fish, I would not remove it, but it is not doing all that much anyway.
Don't listen to anything the store may tell you about having to buffer the pH, increase the KH, blah, blah...here it is completely unnecessary. I had zero GH and KH with the pH in the 4's or 5's in my tanks for 30 years. As long as the fish are from such water, they are in ideal surroundings.
There is just the softener issue to check, though.
alkalinity was originally 120 and ph was 7.2. Gh is 25.
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