Bit of a downer of a post.
Was checking on my cacti and noticed a few had turned a very funny colour, pulled one out of the pot to check its roots and the whole thing was rotten right up the core, not even enough to try and save.
All up I have lost 3 thelocactus and also an Astro.
Guess I was a little too heavy handed with the watering.
So far the rest seem ok, but I will scaling back my watering routine majorly!
I was surprised these ones kicked the bucket because they were planted in the driest mix I use, at most there is maybe 5% organic matter, the rest is pumice, scoria and a small amount of sand.
Ah well live and learn I guess.