Hi all, I am running a Marshall AVT100X with a parallel effects loop and a Boss GT-8. I am having phasing problems that I believe are being caused by the marshalls parallel loop. My routing is as follows:

Guitar into input of GT8
GT8 runs wah and then GT8 effects loop
GT8 Send out to input of marshall (to use marshall preamp)
Marshall send goes to return of GT8 (this effectively gives wah between guitar and amp input, then puts the marshalls preamp on the loop of the gt8)
I put reverb and any other modulation I want post loop in the GT8 then run the main out of the GT8 into the return in the marshall, meaning the gt8 reverb is on the loop of the marshall.

I'm running the loop mix as wet as posible on the marshall but it's still causing phasing problems, obviously the gt8 is adding .2ms of delay or something when running through it's reverb and the amps original signal is phasing out with it as it's a parallel effects loop.

This is a real pain in the backside as you can imagine. I'm sure others have come across this. Are there any ways to keep this sort of routing but get rid of hte phasing problems, without having to get the amp modded to a series loop?