Getting good flow bubble rates with mazzeis can be a challenge due to the fact they actively suck gas into them, vs backpressure from disc, which have their own trade offs(reduced flows and CO2 rates after they slowly clog and as the plants fill in.........)

Not taking into account things like plant growth/biomass changes through time, disc clogging, even if the pH claims the same, the system can really be really changed and you will never see it.

I think if the rate of CO2 is even relatively the same, the limitation is something else.
After any big trim etc, do a large water change.
You'll save shrimp and other fish etc, and cause them less stress and also have less algae chance/potential.

Then you can re set the system with nutrients.
Light, CO2 and nutrients, resetting these will help in virtually every case unless it is something weird with the tap water.

Regards,
Tom Barr