I'd bump your tds into the 200 range, maybe up your gh to 6-7. Just my two cents. I have a 55 gallon that has produced about 500 oebt a month for the last year or so. Everything else seems to be alright to me.
My first round of babies are like 3 weeks old now getting g pretty good sized now. I would have to agree with duke to get your tds up, I try to keep mine between 205-225ish. The females were berried again within 24 hours, and I have not noticed any babies disappearing.
Powdered foods can be messy if it goes uneaten. I use mosura tds up. I remineralize my di water to about 120 with shirakura ca+ then bring it up to like 150 with the tds up. It only takes a pinch in 5 gallons so the bag will last forever. My oebt are none stop breeding and babies appear to be growing great so I would advise using it.