Sounds like your experiencing effervescence. It’s caused by moisture trapped in the wall. You then sealed it in using the Drylok, it couldn’t pass through the Drylok so it came out on the bare side of the wall. It usually happens on chimneys during the winter months. It’s nothing to worry about it’s just irritating. Use a wire brush to remove it and I would suggest a dehumidifier. It will most likely continue until the moisture in the wall finally is drawn out.
Be patient and keep wire brushing until it stops. You might also be sure you have good outside drainage away from your home. Make sure all downspouts channel the water at least 5-6 feet away from the foundation.
if you don't want to wire it off - which would work fine, I think - and be safe. . sometimes people acid it off. But I wouldn't set about to scrubbing anything with muriatic acid if it'll just work itself out naturally - because considering the danger to you it'll continue to efflorescence until it's all leached out regardless.
The leeching is natural process - you can't stop it in it's tracks.
At this present moment in time I am making cabinets for the kitchen - just in case you wanted to know what I'm doing when I'm not around.