pellets and carbon
 

im about to get a reactor vertex 15 and im wondering if i can have np pellets and carbon in one reactor? its a 20g with 10g sump

how are you going to replace the carbon?

it will take a few months for your system to consume the pellets (they are NOT replaced - they are replenished once they are used up)

carbon (IDEALLY) should be replaced every two weeks to a month so you will need to remove it from the reactor and separate it from pellets and put in new carbon.

I think the flow requirements for both are different as well.

I wouldn't mix them. Reason is that you remove/replace the carbon on a regular basis and you only top up the pellets as needed. It would be a real mess trying to do that.

I would either use a second reactor for the carbon, or just run them in bags passively.

As phi delt reefer mentioned the proper flow for each is different. You'll want a slower amount of flow through the carbon so that they don't tumble which would cause them to grind together and release dust into your tank. However with the pellets you do want them to tumble so that they don't fuse together into a solid mass.