Did you check UNDER the leaves to see if you got any bugs where the yellow spots are?
Your girls are not starving, although you could up the PPM/EC somewhat. I wouldn't change the water/nutes that often, perhaps every couple of weeks would be better. When you change the water that often, and if its not mixed right, then you can create more problems than you are trying to solve. Water temps all of a sudden change, EC/PPM is different.... all things they are forced to adjust to. If it gets worse, examine the roots, if they're not looking happy, then perhaps there could be a problem with oxygenating. I wouldn't panic, just keep an eye on them.

SN