Coating on Pool Deck Concrete Blocks

[apoptosis]

I have these concrete blocks about 3' x 1' x 2" that surround my pool and were made into a grill area. A year ago I power washed them to get mold off with a 3000psi electric power washer (Not very powerful). This year I noticed some of the blocks had even worst mold than the previous year, and look more grey than before like regular concrete. (Please see pictures)

I think the power wash removed some coating on the blocks that was a whitish /red. I have tried to figure out what was on them but there seams to be infinate options on staining/ sealing pool concrete online. My question is does any pool builder know what this was on the blocks? Is it something that could be reapplied, or have I ruined them and have to get the pool repaired?

Any help is appreciated.

 

[kimkats]

Here is a bump to get it in front of more eyes.

 

[apoptosis]

Thank you for the bump.