We Hydroponics
...If you want to boost the productivity of your crops, chemistry is your best friend.
And one common household chemical that can make a world of difference in your hydroponic system is hydrogen peroxide...
https://www.greenandvibrant.com/hydrogen-peroxide-hydroponics
Check the pH and EC/TDS in your system. Best choices for hydroponics
ECO209 - Continuous pH monitor
http://www.adwainstruments.com/continuous-monitors/88-ph-monitor/35-eco-209
AD11 - pH/Temp pocket tester
AD32 - EC/TDS/Temp pocket tester
http://www.adwainstruments.com/pocket-testers/99-waterproof-pocket-testers/professional-waterproof-ec-tds-temp-pocket-testers-high-range/85-ad32