Aeroponics is on the cutting edge of growing methods. It presents the greatest opportunity for truly amazing results.
In order to fully utilize an aeroponic system you absolutely must have a high quality meter for measuring nutrient concentration.
True aeroponic systems (not deep flow, NFT, or hydroponic) will fully drain out nutrient between cycles allowing you to use much higher nutrient concentrations without burning your plants.
Many meters will not measure concentrations higher than 2,000 PPM. We typically run about 4,000 parts per million on mature plants. Therefore, we need a meter capable of measuring higher concentrations.
I use the Milwaukee SM802 Smart Meter. It measures the higher limits, as well as pH and EC. It is portable so you can use it on multiple reservoirs.
Growing aeroponically without such a meter is "flying dead stick". You can't possibly ascertain the difference in in parts per million without one. You will have a close mixture when filling your nutrient tank to manufacturer's specifications but as nutrient is consumed you will have no idea how close to the optimum level your nutrient is.
You can use many methods of measuring pH but a high quality meter for measuring PPM (parts per million) may also measure pH.
"Aeroponic" systems with poorly designed drains (not enough slope, small drain ports, bottom mounted misters, drain risers, or large net pots requiring grow media) do not drain out sufficiently to allow maximum nutrient concentrations.
Poorly designed systems will be plagued with root rot and other maladies.