Okay so if plants are growing fast you have to increase the Co2 .

Plants will and can depelete the CO2 in a system, but generally this is within the plant groups, eg it might be only 15ppm in dense plant beds and maybe 40 ppm near the water return where the incoming CO2 rich water enters.

You need 3 things basically:

1. Low/no current in the area/region of interest
2. Active plant growth
3. Little degassing(which can be part of #1)

You can still have good current and little degassing.
You can also have good current, but dead spots.

Generally, maybe 5% or less is used by plants for CO2, this might even be generous.
But.....we add a higher ppm to ensure all the plants, including those dead spots have more than enough.

CO2 is hard enough to set and dial in correctly, fiddling with it each and every time you do a trim seems laborious and more likely to louse things up real good versus just leaving it alone once you have it set correctly.
A pH controlled system would be the best solution if you felt this was an issue, but even there.........you still have dead spots etc.

 

Plants will and can depelete the CO2 in a system, but generally this is within the plant groups, eg it might be only 15ppm in dense plant beds and maybe 40 ppm near the water return where the incoming CO2 rich water enters.

You need 3 things basically:

1. Low/no current in the area/region of interest
2. Active plant growth
3. Little degassing(which can be part of #1)

You can still have good current and little degassing.
You can also have good current, but dead spots.

Generally, maybe 5% or less is used by plants for CO2, this might even be generous.
But.....we add a higher ppm to ensure all the plants, including those dead spots have more than enough.

CO2 is hard enough to set and dial in correctly, fiddling with it each and every time you do a trim seems laborious and more likely to louse things up real good versus just leaving it alone once you have it set correctly.
A pH controlled system would be the best solution if you felt this was an issue, but even there.........you still have dead spots etc.

 

I've never seen fish respond poorly post trim, typically the other way around since there's often more current and a bit more O2 and degassing.
If you uproot and pull up a lot of muck............then do a large water change, this mitigates any of the uprooting low O2 issues and organic matter.

So as long as you do the water change after the big hacking........you are in good shape.

Matt;'s hairgrass tank is not particularly a big nutrient hog, the few stems are the only thing and the fish waste along with relatively newer ADA AS takes care of the rest.
Hairgrass is pretty tough overall.

 

I've never seen fish respond poorly post trim, typically the other way around since there's often more current and a bit more O2 and degassing.
If you uproot and pull up a lot of muck............then do a large water change, this mitigates any of the uprooting low O2 issues and organic matter.

So as long as you do the water change after the big hacking........you are in good shape.

Matt;'s hairgrass tank is not particularly a big nutrient hog, the few stems are the only thing and the fish waste along with relatively newer ADA AS takes care of the rest.
Hairgrass is pretty tough overall.

 

If you can manage a single species well and have consistent and nice throughout a tank, then also do a nutrient hog stem plant tanks, manage that well, then a low light tank...........and maybe a non CO2 tank............then you pretty much run most scenarios.
Awhile back on the net, I realized I can talk a great talk, but without nice examples of scapes and pictures, it's not really that strong of an argument.

You show a nice tank, thriving plants, scaping with the rare and hard to grow species under a wide range of conditions, then you pretty much can do whatever you like.
Plenty of folks can simply grow plants, but can they scape well with them? That's the REAL goal.
Many lost sight of that goal, others can do nice scapes, but are not that good at growing them, so they accept they can only use X, Y and Z plant species.

Persistent attacks on your own goal will get you there.

 

If you can manage a single species well and have consistent and nice throughout a tank, then also do a nutrient hog stem plant tanks, manage that well, then a low light tank...........and maybe a non CO2 tank............then you pretty much run most scenarios.
Awhile back on the net, I realized I can talk a great talk, but without nice examples of scapes and pictures, it's not really that strong of an argument.

You show a nice tank, thriving plants, scaping with the rare and hard to grow species under a wide range of conditions, then you pretty much can do whatever you like.
Plenty of folks can simply grow plants, but can they scape well with them? That's the REAL goal.
Many lost sight of that goal, others can do nice scapes, but are not that good at growing them, so they accept they can only use X, Y and Z plant species.

Persistent attacks on your own goal will get you there.