Its an acid wash but I don't think this is dyi. 

Hi Team,After some months, taking care of important topics at home, I want to go back to get a property for buy and hold.Some mental notes that I want to run an acid test with the collective and amazing knowledge on this forum.With the current market situation, where depending on the source we are going into a recession (others will say that we already are) Will be the case that most of the Turn Key providers, are selling a Street Price?

Is it possible that the stain is tannic acid from the subfloor?

(for about an hour) and according to the manufacturer, that is okay (only w/ white distilled vinegar and not an acid based descaler)Hope that helps.

I used a water-based stain instead of acid-based, and it was extremely simple.

A third use is lead acid for batteries.

You need a special license/permit thing to store chlorine and acid, and if they ever leak and mix together, you'll be in huge trouble.

Pouring a wheelbarrow load of boric acid and sugar maybe will cut them down.

If the floor is only stained I don't see why a good etching with acid wouldn't open the concrete pools again as well for the mortar to stick.If the floors have a clear coat no matter what you put on top its only going to bond as strong as the clear coat bonds to concrete so it may need to be removed.You can test clear coat adhesion by scoring an X in the floor then placing gorilla tape or similar over the X and see if anything pulls up.

Make sure the company has been in business a long time and that they do the acid etching prior to the spraying.You can have the sink done too but honestly, I think a few bucks more for a new one will give a better impression.