Synsepalum dulcificum miracle berry plant problems

[namc]

I bought this plant from Logees about 2 months ago. It arrived healthy and I followed the instructions to replant it in 1:1 sphagnum to perlite soil. A few weeks after repotting it began to show the symptoms shown in the attached pictures.

It gets low intensity direct light from led grow lights on a 12 hour timer. I know the red leaves indicate its still too much light so i will probably move it out from directly under the light. I am not overly concerned with the red leaves. I water with RO water when the top 1-2 inches of soil is dry. The room its in is pretty cold averaging around 60F.

Before it started showing symptoms I had a minor case of fungus gnats that i treated with sticky paper and a soil treatment of mosquito bits. I havent had anymore problems with the gnats but not sure if the bt caused any harm to the plant.
Ive tried to treat the plant after showing symptoms by first adding sulfur to lower the ph which currently sits at around 6.8. I know the sulfur will take a few months to make a noticeable change to the ph so i also added a small amount of aluminum sulfate a few days later. Then, I added a slow release, 5-5-5 organic fertilizer to the soil. I chose to use organic because I read that the plant does not take well to high salt levels. A fungus showed up a few days after adding the fertilizer (see images). A week or so later I applied a foliar iron spray to address chlorosis. I have given it a few treatments with neem oil because I thought it may be leaf spot or similar. I havent continued with the neem oil treatment.

I admit that i am just throwing solutions at the plant because i dont exactly know what is wrong with it so any help is appreciated.

[Daintree]

Ok, a couple of things. I think you might be killing it with attention.

The pot is probably too big. It is holding a lot of water. Forget the top two inches and stick a spoon clear to the bottom of the pot and pull out a bit of soil. I bet it is sopping wet. I am guessing the leaves look like that because the roots are drowning and can't pick up enough nutrients.

Organic fertilizer doesn't work in potting soil because there are no beneficial micro organisms in the soil to break them down and deliver them, months later, to the plant.

I don't know how on earth almost straight peat moss can be giving you a pH of 6.8. Are you measuring the pH of the water??? Stop the RO water. pH is too high. Just use rainwater. Rain water should be about 5.5 or so.

 I would repot in a smaller pot, in 2/3 peat, almost 1/3 perlite, and a bit of regular potting soil. I always put some small chunk bark on top of my pots as a water breaker, to keep all the perlite from floating to the top.  Mix some Osmocote Plus into the top inch or so of soil and quit putting everything else on it.

Don't worry about the red leaves, you are probably not giving it too much light. Mine always come in with red leaves and they are pretty big and fruit like crazy.

Carolyn