Hi chirpie! Welcome to ATP!
Can you describe the location in your garden, where you have the hanging basket. Is it in full sun? Or what orientation is it getting the sun, south, west or east? I would try to move the basket into a part sun/part shade. Also how are your temperatures right now?
In my area, since it is just so bone dry here and our temps soaring, I have to thoroughly water my similar cacti at least once a week. I have it in part sun and part shade. It seems to be really okay when temps are just mildy warm, like 70 to 80F, but our temps are going much higher than that, triple digit heat here at times. So I would also give midweek light watering, and I do my watering direct to the root zone. I do the watering early in the morning.