The rock I tried to smooth off is in the very center of the photo (whitish patch). In other words, that rock is not caliche, and is not softening. That's good. The best I could tell, there was no fiber in the concrete that flaked off after 20 years. So I'm going to put a thick reinforced patch over those areas, then several coats of Drylok. I just picked up $600 worth of the latter in town today. Then gonna get some Quikwall for the patches. Here is the problem area. It's fixable.
Basically, the whole west wall near the floor has a ridge of underlying rock that was stuccoed over without mesh. As far as I can tell, the floor has never leaked and the Drylok should take care of any pinholes in the walls where there's mesh. So if I can just beat the rains, I should be good to go. One year my tanks all filled up in January so one has to always consider it could possibly rain before I finish. Therefore, I'm going to do that "fault line" next.
Here's that first hole after I cleaned it out a bit.
I didn't manage to apply more than one gallon of coating this morning, Using a ladder is slow-going. Maybe one of these days someone will drop by and take a selfie for me. I'm not able to do it right by myself.
Note the hole on the left side of the photo. The fault goes all the way from there to the gray patched area to the right of the ladder. This is the kind of project a person postpones until their tank leaks 3 or 4 thousand gallons a day. I fantasize about putting colored coating on any areas that show above the high waterline, which will have to wait until next year when the line will become evident. Then it'll all match.
No time for birds and butterflies today. I saw lots, but nothing different.