Efflorescence maybe but I have never seen it that bad. im thinking moisture was trapped under the sealer and that can turn the sealer white while it is curing. A lot of DIY's will power wash and apply the sealer right away.

If that is the case you can either strip off the bad sealer and start over or get xylene. I've never used it myself, but it is supposed to emulsify the sealer enough to let the moisture escape.

That is very likely sealer with moisture under it. Like Jeff said, get Xylene and a good Chapin "pro" sprayer, the red metal one with the brass hardware. Also get a 16" roller and a roller frame to put on a broomstick. Sometimes you can just spray on the Xylene and the moisture will come out, sometimes you have to roll it out a bit. Spray the Xylene on pretty thick and let it sit for a little, then roll and redistribute the sealer. I have done this many times. Try it on a small area first.

If for some reason the sealer tuns white again, there may be moisture coming up through the concrete for some reason. In this case the sealer should be stripped off and a different type of sealer used. If this is the case, I would hand this off to a reputable concrete contractor, or have the customer pursue it with whoever did the sealer in the first place.

Its not salt or chlorine water. She mentioned what it was but just i cant think of it but its pure water basically.  It used to be stained concrete and then they put sealer on it. Maybe that could be part of it.  And it looks kind of like a thicker old sealer on it. She didn't want me to use much pressure at all to clean it! She basically just wanted water hose pressure to clean it. She Thought  I would chip the concrete. And that could be it. If its never had a really good pressure washing to get the seal off, they could just keep sealing over old seal but they're having a wedding in a few weeks there so they just wanted a quick fix so I sealed it and it looks good for now but they said eventually it will turn white again and they've been dealing with for too many years so after the wedding their going to redo the whole pool area. Which is fine with me I can move on to the next project. Thanks for every ones help!