Overwatered cactus

[Hard@it]

I have a 200mm round cactus which has come out of its pot,(because of stupidly overwatering). I did not delve into the underside to see if it was ok as I thought best to leave alone. I have now repotted it in a drier medium and am keeping my fingers crossed. I am hoping it is not dead as it still looks healthy. Any advice on this and also how deep do cactus roots go ?
Please note I have learned my lesson.

[Thunderbird+]

Hi Hard@tit, Nice to see you again, Hopefully you have realised you wee mistake early enough and it will be ok.
I cant think of anything much other than what you've done to correct it other than treat it to some special cactus fertilizer like 'Chempak' Around �1.80 for a small tub. Hope that makes it feel happy ;-) Tbird+

[Hard@it]

Hi Thunderbird+, thanks for the "cheery" hello. As you can obviously see I am not in any way an expert in cacti,(although a know-all about other stuff), and am trying to apply commonsense to this regrettable problem.
I was rather disappointed in not seeing long roots, but that is maybe how it should be. Came accross Planetcactus site, so signed up but will leave for a day or so before posting there as an ABer may come up with something.

I do have Chempak, but as you are aware it may not be good if I overdo it, poss. in 2-3 days after a dry out I could give a bit of a treatment.

Thanks again, Cheers Hard@it