Hey,
Looking at your diary,
Are you running DWC and top feed?
That would be a great combo as my first recommendation would be to rinse the clay every week or so so prevent salt buildup.
The other critical things to control, in my opinion would be solution temp and ph.
Ph being a given, I'll leave at, maintain between 5.5 and 6.5.
Solution temp is critical to avoid mold and increased reaction speed of your solution.
Think of your bucket as one big chemistry experiment, colder temps result in your nutrients breaking down slower. 17 to 21celius is a good range.
Finally, these unwanted reactions can create compounds that the plant has trouble absorbing. To avoid this, every couple weeks, remove half the solution and discard to remove half the complex salts.
This is a partial list but, to me, the most important. I do not use any type of hydro guard or peroxide and my solution is cristal clear with no smell. I keep my solution at 19C.
I hope this helps,