Between the bugs and the deficiency I figured it was root snot. It happens when there is a poor condition somewhere in your res whether it be improper temps, non-sterilized (using organic nutrients),no air stone,etc. You need to rinse the roots in another bucket or something then clean everything from the tub,pumps,hoses,any tools you may be using like pH meters, ppm meters etc. Once you get everything cleaned up make a new batch for the res and only use synthetic nutes. Change your res every cpl weeks or (depending on how clean you keep it) longer if you manage it well. If your hydroponic grow is small just buy the 3% h2o2 from the drug store and add 8-10ml to every gallon of water you add to the res. This will be enough to keep your res clean and steril in between res changes. Keep your res temps below 72 and you will hardly have conditions for root snot. Keep the res supplied with plenty of oxygen with lots of bubbles/airstones. If you dont use a water chiller, here's a couple things you can do that will help with keeping res temps lower:
-you can keep the res on the cold ground and insulate the outside of the res with styrofoam to help keep it cool.
-If you can, keep the res in a dark area out of the direct grow light.
-If you have a tote style res with the pots in the lid, you can paint the totes and the lids white.
-use small dual diaphram air pumps for the res. Larger air pumps put off lots of heat and this blows into your res through the bubbles continuously raising your res temp and making it a breeding ground for bacteria. Small dual diaphram pumps run cool and if needed you can use 3-4 dual diaphram air pumps and it will still be a tiny fraction of the heat a single large pump would put off.