Anyone know anything about repairing rock work (is this the correct thread?)

[tagteamcomputing]

I have sandstone around my fountain and hot tub. The grout is old and giving way so I pulled the rocks up and found a lot of loose rock under those. It looks like they put a row of rock, then grout or concrete in the middle and then another row of rocks. I have included a link to an album that shows my pool and you can see in the picture with the white bucket what I am talking about.

Rock Repair - Google Photos

I am wondering if there is supposed to be loose rock or gaps in there to let the water flow through and for contraction and expansion. Or is that all just old grout or concrete and that should be totally filled in and then use some grout to lay the sandstone back on top.

Thanks for any help and if this should be in another thread just let me know.
Thanks,
Tate

 

[Arizonarob]

From the looks of things, it does appear to be some erosion of the subsurface. Here’s a bump to get your thread in front of more eyes.