Hmmm.........you need to flush....no doubt about it imo. You can use regular tap water and if you are trying to RAISE ph then ph your tap water to 6.2. If you are trying to LOWER ph then make your tap water to 6.8.

My personal feeling is that they are burned from overnute and that's what has thrown off your ph. Generally you will need 3-5 x the amount of your pot of water to flush with. I do my soil plants in the bathtub if I have to flush them. If you have them in 1 gallon pots you will probably need to flush with 3 gallons of ph correct water before you have gotten rid of the crud inside.

Once the water coming out the bottom is in normal range; water with 1/4 strength nutes at the correct ph and let the plant dry out. Overwatering your plant ONCE (as in flushing) won't kill your plant with root rot etc. HOWEVER.....you might want to consider getting a good product like Cannazym which helps prevent root rot. As you are discovering.....if the roots aren't happy....your plant won't be either and it's really that simple. You also must make sure that you have adequate drainage in your pots so that drowning/suffocating the roots will not occur.

Take care of your roots!!