If it keeps blowing off immediately I'd try taking the end off the hose and either dump it in a clean bucket or run it into the top of the sump on the tractor.   Might have to add more hose to get there.

I'd want to do that to figure out if the problem is on the planter or if its the coupler/tip or at the tractor.    Couplers/tips have been known to go bad.


That soft hose held on with hose clamps is there for protecting your hyd motor (its supposed to blow if there's a problem) so whatever you do, don't replace it with a threaded on hyd hose.     You definitely have a restriction somewhere that needs finding.    We've run 4 different White planters over 40 years, only time we've ever blown that hose off is when someone forgot to hook up the return line, and that hose did what it was supposed to do.