this seems to be a touchy subject for some, you will get ppl saying to flush & some strongly advise not to. i use waterfarms as well & flush the last 2 weeks.
http://www.ebay.com/itm/Alita-Air-Pumps-airpumps-AL-6A-AL-15A-AL-40-AL-60-AL-80-AL-100-etc-etc-/330740199172?pt=LH_DefaultDomain_0&var=&hash=item4d01a6ef04#ht_2355wt_1034
They have various sizes to suit your needs i personally use the al-100 for 16 water farm units for both drip & airstone in each.
https://www.rollitup.org/advanced-marijuana-cultivation/200413-fimming-my-blaze-complete-how.html there is also another one about topping also just gotta search it pretty neat write up with descriptions & pics.
https://www.cannabis-seeds-bank.co.uk/gage-green-grape-stomper/prod_3308.html
I've done one round of this went into flower @ 36" & finished at 9+ft. It was a good looking plant great appeal but just a little above average yield. Maybe a few runs I may be able to get her down & have a more...
I use supernatural brand gro aqua for veg/bloom aqua for flower additives being supernatural ultimate thrive & some cal mag. Works for me it's simple but isn't cheap. Also leaching weekly is recommended & i use there lineup of super leach.
I had an issue with rot in dwc caught it pretty early & a buddy suggested adding dutch master's zone into my res. It helped out a ton i still had minor rot but i think it was the roots that were already affected. Since adding it my root mass has gotten bigger and never had any signs of rot since.
Not saying this is the issue but just throwing it out there. Do you have the correct wattage going into your ballasts? Maybe something weird going on with the wiring behind your outlet.