Hey JJ, so your plants definately look deficient, but surprisingly with such a small air pump you have a nice looking root system
. I think that due to your situation, it might be best to do the following things:
1) change your feeding regimen so you get a nice healthy green on your plants
2) upgrade your pump / airstones to handle the bigger root systems you will encounter soon
3) teach you about pH'ing your solution
1 - So, while dynagrow is not a bad formula in itself, I think that the 3 part from General hydroponics may be your best bet because it has very easy feeding schedules to follow, while providing a good base nutrient for your plants. If you are looking for an even faster recovery, adding a vitamin additive in addition to foliar will help but let me know if you have the budget for that
http://www.hydrogardencenter.com/florabloom1qt.aspx
http://www.hydrogardencenter.com/floragro1qt.aspx
http://www.hydrogardencenter.com/floramicro1qt.aspx
2 - While your plants are looking 'relatively' healthy (not dying basically), the airstones and airpump you are mentioning will get you through earlier phases, but in order to maximize feeding, you need to put oxygen to your root system! Through my personal experience, I have found that buying small parts and then consistently replacing is too expensive, so these are parts I have found that work best and can be applied in many different applications so you won't have to buy anymore
http://www.hydrogardencenter.com/airstoneround4.aspx
http://www.hydrogardencenter.com/commercialairpumpwith8outlets70ltperminute.aspx
3 - WELLLLLLL I sincerely hope that you are not replacing your nutrient solution whenever the pH drops below a certain level
. That is why the hydroponic gods created acid and bass for us DWC growers who really need it for all the interactions in the solution. Whenever your plant absorbs food it is interaction with the solution and changing your pH (the exchange of ions in the solution and chemical byproducts / root secretions are primarily responsible). Instead of replacing your solution, use hydroponic specific acid and bass to get your pH solution around 5.7. This will make your plants nice and happy (and add acid and bass very slowly because fixing a mistake is harder than having to add a little more at a time). For this I recommend going to CVS or some pharmacy and getting baby droppers. It allows you to manage the solutions in the milliliters and be more accurate.
http://www.hydrogardencenter.com/phdownacid8oz.aspx
If you have any more questions don't hesitate to ask!