Sorry for your losses, single stage apparently.
https://www.ukaps.org/forum/threads/does-anyone-own-a-jbl-m001-regulator.32366/
Your choices are -
1. Keep an eye on the cylinder pressure and replace before EOTD (waste of gas but better than dead fish).
2. Replace single stage regulator with a dual stage regulator.
3. Use a pH controller and set it to switch off just beyond where your current injection volume maximum levels are.
4. No supplemental CO₂.
Either of these four things will prevent EOTD casualties.
Option 1 is not fail safe (subject to life gets in the way sometimes - likely)
Option 2 is near fail safe (subject to user error or material degradation - less likely)
Option 3 is near fail safe (subject to user error or material degradation - likely user error - likely pH probe lifespan (can be mitigated through readjusting controller to new profile even if the pH reading is inaccurate compared to titration testing)
Option 4 is a lot tougher than its made out to be if targeting fussy plants.
There's always the belts and braces which is a combination of Option 2 and Option 3 (not 100% safe as belts and braces are still vulnerable to user error and material degredation).
Read enough about EOTD to never want one, it's not easy keeping the plants happy and not killing the fish with added CO₂, it's all about a happy equilibrium and it can be a tough road to walk.
🙂