You sure can.
DWC -The hard truth about % DO Saturation and PPM DO Concentration simplified… You can keep guessing, hoping and praying every day that your res water DO will be "safe" for your crop and Bennys or if you really want to know if you are winning or losing the DO challenge of insuring safe oxygenation in your DWC or RDWC res water, well that's easy to do and it's simple…. Test your DO with a DO meter or DO chemical test strips. The test strips are cheap, $1 a test or so.
It is really popular not to really know what DO surprise awaits you when check your roots every morning, Always watching for the dreaded symptoms of root rot... and the Pythium outbreak. Oh the routine morning anticipation of looking at your roots not knowing what surprise you might find every morning is sort of exciting for many growers so to speak.
If your DO saturation is too low, simply add more oxygen, if your DO Saturation is within the “safe range”, don’t worry, be happy and roll up a big one, get laid and chill out because your DO is safe in your res water.
But, if your DO Saturation is too low, you really got big problems and if you do not fix that low DO problem, you will have sick, dying, dead and decaying roots and you can bet your 1st born child (legitimate or bastard child) the fungus is always present and will colonize and thrive on your dead marijuana roots.
All that aggravation and heart break is predictable every time your DWC/RDWC life support system fails to support aerobic life forms.
Adding more air, air stones higher water falls does not add more O2, because air is always 80% Nitrogen and 1/5 oxygen (O2) and Mother Nature absolutely controls that mixture of gases, not you. Mother Nature calls the shots and the oxygen is air is a limiting factor when elemental oxygen (O2) is necessary in any life support system.