i feel you need a new bulb. it is no where the intesity it was when you started growing. and the fact that you were able to grow a few times using the same process i dont think ph is going to be your problem. if i were you i would do my best to get the plant into its perminate growing medium from the begining. you are causing some of the problem with stress by moving as i have seen 3 times. each moves leaves to the problem of stress. with that you could also be introduces anything like nicotine if you smoke. germs of any kind and such that could be harmful to your plants.
if you plant on moving to a new nute. i highly recommend using cutting edge solutions. it is a great company that only make 1 line of products. there is no guess work to what other kinds of addivitves to use they aonly make 3. micro grow and bloom. and they also offer the icing on the cake with plant amp,cal mag and uncle josh's. these 3 additives are not necessary buut like i said icing on the cake. ebay has a great deal at 160 bucks delievered. it contains 1 gallon of micro,grow,bloom and quarts of uncle josh,plant amp,cal mag. they contain a ph buffer and make there no need to adjust your ph. they take the guess work out for you. one less thing to go wrong.
but i would deffinatly change you bulbs in your grow area as they are well past their expected life spand