Is My Cactus' Soil Too Loose?

[mpetro]

I noticed my cactus has been looser in his soil. It looks as though there's less soil each time I water. Is this possible? I mean, the point on the pot where the top of the soil reaches now is lower than a few months ago. Is that normal and am I supposed to just add more potting mix to the top as it shrinks? Of so, does it matter if I add more of just the rocks or just the dirt-like soils or both?

I also am wondering if him being looser has something to do with his roots being more in a line than a circle under him. I'm not sure if that makes sense. For example, if the roots seem to extend from east to west, but not north to south. I think that's what's making him easy to push north and south, but not so much east and west (but still some overall).

I've repotted my cactus at least twice in the past year and worry if I repot again, it will hurt him. But if his roots need to cover more area below him and spread out in every direction (not primarily 2 directions like his roots are now), would it be okay to repot so soon?

Here's a link to the last time I repotted him with photos that I think might make more sense of what I mean by his roots not being spread in a circle below him: https://cactiguide.com/forum/viewtopic.php?f=25&t=44324

I've also noticed he's grown fuzzier, especially on top at the tips of his tubercles (is that the right word? where his spines grow out of) and a few spots in between (aerioles?). Where one of his spines/tubercles is missing, there's also some fuzzies growing around that hole. I think that's a sign he's growing, right?

Here's a current photo:

IMG_20200722_114636_compress78.jpg (71.75 KiB) Viewed 2126 times

The soil definitely looks lower than before, this is from when I last repotted him:

IMG_20200404_195431_compress7.jpg (74.51 KiB) Viewed 2126 times

Let me know if I should repot and rearrange his roots or simply add more soil to the top or something else!

[greenknight]

He's doing great! He's plumped up and he's growing - yes, the new fuzz is a sign of growth, new spines should appear soon.

The potting mix is settling, this happens if you don't press it down well enough. Not a problem - add some more to restore it to the original level.

It's not really important how well the roots were spread out as long as they're not wrapped each other around like they were when you first posted, as new roots grow they'll spread in all directions. There's no need to disturb him again now.

Tubercles are the green part, bumps on the cactus body - not all cacti have them. Areoles are the spine cushions - all cacti have them, it's what distinguishes them from other succulents. The low points between the tubercles are the axils - the same term is used for the angle where a leaf or branch comes off any plant. Mammillarias have split areoles - part is on the end of the tubercle, part is in the axil. The part in the axil is normally where the flowers develop, some have fuzz and/or hair there as well.

I repeat - doing great! He looks like a different cactus now, one that's thriving.