My husband has a J-tube with pump because of a previous stomach surgery. We have to very carefully increase the rate of feeding to prevent nausea/bloating. He is at 180ml/hour now and it takes about 8 hours to finish his feeding, which we do at night. I know this may not be your method at all, but maybe if you cut down the rate/amount of liquid per feeding and do it one more time a day it might help, putting it in slower and a lesser amount. We were told to also remain upright and not lay down for at least an hour. Another old trick for nausea is to whif on alcohol swabs or just open the bottle and whif.