u/GroundbreakingAd8730

Had this Gollum jade for a few months now and despite some small new growth it’s quite slow and it’s always had a yellow tinge but it’s slowly been getting paler.
I’m thinking probably just a combination of too much light + heat as I had it in with my cacti under around 600umols of light and 30°c temps during the day. after doing the research I should’ve done ages ago I’ve moved it into a separate grow area where it’s getting around 400umols and around 25°c during the day but I’m also wondering whether the yellowing could be caused by either over-fertilising or over-watering but I’m hesitant to say so because it’s in near enough 100% inorganic and in a small pot so I end up having to water once a week or else it shrivels up dramatically, I also fertilise every other watering with cactus and succulent focus fertiliser at 1/4 dose.
Just wondering what’s causing the yellowing and whether it will heal over time if I fix the issue or will i just have to wait till it pushes out new green growth?
Thank you for any help :)

I suspect mites and have ordered DE and spinosad but I’ve spent the last 5 hours staring at all my plants through a 60x jewellers loupe and haven’t seen a single insect whether it be spider mites or thrips which makes me worry in case it’s something else.
The loph has recently been repotted and placed into a grow area with half its usual light (around 400umols) whilst it recovers so I don’t think it’s light-burn especially as it seems to be spreading from the base of the plant upwards, the base is quite soft and dark but I did raise the plant a bit during the repot so I think that’s just previously hidden corking and also staining from the substrate during watering.
It’s in pretty much 90% inorganic and I water it around once a week, grow area is around 31°c at 25% avg humidity with a fan on near constantly to regulate the temp during the day so I feel comfortable with the more frequent watering as the pots seem to dry out extremely quickly, they get fed monthly with 1.4:0.7:2.7 cactus and succulent focus fertiliser.
The skin of the loph has looked quite sand-blasted for a while but it’s only recently that the cracks have started to appear and also some very small red-brown dots across the whole cacti as well as just turning paler as a whole.
Like I said I suspect mites or thrips and will act accordingly but I’m not convinced it isn’t something like rust fungus or light-burn or maybe even too much wind? Any help from more experienced eyes would be greatly appreciated.