Sisters dont have any similarities

Hey all, im growing a few different plants, problem is 1 blueberrygum plant, ya see ive got two of them growing side by side, same light same soil etc, but one of them seems abit droopy compared to the other one, is a couple of iches smaller and generally a little bit droopy & not as sturdy as her sister, i noticed that water ph level must of been around 4.2 last time i fed them, so ive bought some ph up to remedy this, but i dont know if this is the problem as all the other plants im growing are ok, there 3 weeks old, 18-6 light cycle 600w hps lights in allmix, ive attached some pics, is this anything to worry about or am i being overcautious. (pic 1-6 droopy plant----7 good plant).

any help would be most useful

Flush the soil with water of around 6.2/6.5,once the plant's have been flush leave the grow medium to dry out,some plant's do wilt when been watered so don't worrie if the wilting gets worse for the few days after the flush.Flush till the run off is clear.Then make a batch of nutes up just before you need them and ph to the same has the flushing 6.2/6.5.Here are a few reasons why plants wilt over watering,ph been too low or too high,most common over nutes.make sure that the ammount of nutes that you are adding is not too high.Some plants can handle stress better than others,this is mostly due to the root structure.What i'm saying is if two plant's are growing side by side and one looks alittle stressed then the one that shows no signs of wilting or stress will have afar greater root sytem.I would strongly advice spliting the two while you still have the time.By doing this you will see a great improvement in both,has you can lower the nutes to suite or higher what ever the case may be...tyke

thanks tyke im going to try that now, i thought that maybe because the ph was down last time id watered that maybe they didnt get the nutes needed,
do they look ok otherwise?