Splitting canister outflow to add in-line accessories?

[Shrimplet]

Hi, I've been keeping planted tanks with varying success over the past decade but I think it's time to upgrade to include CO2.
I currently have a 330l tank with a Fluval 406 filter which I plan to replace with Aquael Ultramax 2000.
The Aquael filter has 19/25mm non-standard tubes and every accessory I can find has either 12mm or 16mm ID fittings. From a simple cross sectional area calculation, I think two 12mm ID tubes are roughly equivalent to a 19mm ID tube.
I'm thinking of splitting the outflow from 19mm into two 12mm tubes, attaching a CO2 reactor to one side (and potentially an inline heater to the other in future). Both ends would enter the tank separately, although could combine?
I expect the side with the CO2 reactor may flow a little slower than the other side, but can you see any big issues with this set up? Does anyone have experience with this sort of thing?
Cheers

 

[Aqua sobriquet]

I don’t think two 12mm will cut it. I’d go for two 16mm or a 12 and a 16.

 

[Paul Willi]

Hi
JBL do a co2 inline diffuser 19/25

 

[Shrimplet]

I think you're right, the increased surface area of the two tubes would increase friction and reduce flow, so it would need the larger diameters.

Thank you so much for letting me know about the JBL inline diffuser, I'm going to go with that for now! I may add a reactor one day if needed but this will simplify things a lot. I was dreading having so many connections (and potential leaks!).