I found these ph balancer gadgets and wondered if anybody uses them, they claim to keep ph between 5.7 and 6.5 with most between 5.8 and 6.2 and will last for several months between recharges done with a special solution.
https://growershouse.com/perfectph-natural-ion-ph-balancer-capsule
https://www.ebay.com.au/itm/Torus-Hydro-Perfect-PH-130L-35-Gallon-PH-Stabilizer/264430231475
https://growershouse.com/perfectph-natural-ion-ph-balancer-capsule
https://www.ebay.com.au/itm/Torus-Hydro-Perfect-PH-130L-35-Gallon-PH-Stabilizer/264430231475