Flow rate drop with external CO2 reactor?

[illumnae]

Just wanted to ask if anyone know how significantly a CO2 reactor will drop the flow rate in a canister filter. Currently, i'm using an ISTA mix max L size with my Eheim ProII 2028 to mix my CO2. It works well, but i'm pretty sure flow rate is cut as i have to step down the hose from 16mm to 12mm to fit it into the reactor, then step it back up again to 16mm at the outlet to fit into the provided rainbar.

I'm now considering upgrading my filter to a Fluval FX5, which uses 25mm hoses. If that's the case, would using the ISTA mix max would be counterproductive as i'd have to step down from 25mm to 12mm then back up to 25mm again? Would it drop my flowrate to equal that of the Eheim 2028 (fixed flowrate coming out regardless of input), or is it a similar percentage drop or a higher percentage drop?

If the flow rate is going to drop significantly, what would be the best way for me to inject CO2 into my tank? I don't think there are any commercially available reactors that use a 25mm or even a 16mm hose size right? I'm not very DIY savvy so i'd like to avoid making my own reactor if possible. Would misting with a diffusor be the only solution?

[o2bubble]

I think you can view is as the drop in flow rate is proportional to the decrease in diameter of the pipe from 16 to 12mm. So theorically should be about 4/16 = 1/4 (25&#37 drop in flow rate.

[illumnae]

so the drop in flow rate if i switch to the Fluval FX5 will be > 50%? wow...i need to find an alternative method of dissolving CO2 into my tank...any suggestions?

[o2bubble]

Theoritically yes but depends on how efficient is ur filter pump also. And having bigger outlet does not mean more water output from filter and thus higher flowrate.