My temp is 82F, pH 8.0-8.2, TDS is 270.
They have been there for a while and doing fine, but for some reason they disappeared one by one, until only 1 berried female left. Then she gave birth to 3-4 babies.
Clarify, it's Sulawesi cardinal, not Caridinal
Increase your pH to 7.5 or so (do it gradually). Also they like hotter temperatures versus other dwarf shrimp, low 80s. They seem to be able to handle a wide variety of kH and gH, but I think in the lake they come from they are relatively low actually, below 4 for both. If you improve your condition baby survival should go up quite a bit. With all the problems I've heard about keeping Sulawes I am surprised they are doing as well as they are in your conditions.