We used gel baits, IGR (insect growth regulators), diatomaceous earth, and boric acid to get rid of them -- haven't seen any more of them in more than a year -- not sure how long they had been there. 

Depends on the water , if its acidic , 10 to 12 years , if its not maybe 15 to 20 .

I won't pay Starbuck's prices for bitter, acidic coffee. 

Boric acid - white dry powder - plus no water or any liquid.They will be gone in couple days

Work it in with an acid brush and rinse.  

Matthew Spiegel my understanding is that only new concrete can be stained because the acid stain will react with the limestone in new concrete to give you that glossy look.

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.