Boss GT-6 through Mesa parallel fx loop

[ebmm]

I recently bought a Mesa Rectoverb combo w/ a parallel effects loop & I can barely hear the modulation effects when running my GT-6 through the loop. I have the signal on the GT-6 100% wet & have the loop mixed at about 50%. The delays are coming through ok, but no chorus, phaser, etc.

 

I know these multi-effects are often run in front of the amp, but I don't use any of the amp modeling & really prefer my effects after the preamp (especially delays).

 

Previously, I've run it through the serial loop on my 5150 & it worked perfectly. Anyone else had this problem running the GT-6 (or even the GT-8) through a parallel effects loop? Any help would be greatly appreciated.