The pump has an input side and an output side. You just need to connect the input side of the pump to the OUTPUT side of your CaRX. The alternative would be to connect the output of the pump to the input of the CaRX.
This is how I set mine up on the new sump. I used hard 1/4" pipe to draw from the sump it goes to the ca/rx, on the output side of the reactor goes to the kamoer. And then returns to the return chamber and drips from there