PLANTER PROBLEMS

we have some hyd issues with our new planter setup...pulling a 17-90 12 row JD with inter plant and auto row shutoff with a new new holland T7 235 CTV ..the ccs fan and lift are on priorty one set at 12%flow..works good..the two vacuum fans are on the next two remotes set at 9% each..the vac fans are surging,not holding a steady vacuum..any one with a similar setup ?? thinking of adding flow controls into fan plumbing and setting remotes at 10 or 11%.