Water Pumping Newbie

Hello,
I have been pumping off and on for the last 9 years. I have always used air until recently. Read the forums and bought a brake bleeder kit after trying to pump with my regular hand pump. I had a good pump the first time, but water went everywhere because the pump was not designed for fluid. Bought the bleeder kit with the reservoir and haven’t had much luck. All I seem to do is make a mess.

I read that you should only fill the tube a third of the way and keep the tube pointed up, which I have done. My issue is that there still seems to be air in the tube, and I cannot handle more pressure to get the rest out. I tried using more water, but that only filled up the reservoir and left me with the same result. Obviously I know that I need to go slow and not to push myself and risk injury. Does anyone have any tips or suggestions? I know that was going to take some time to get used to just like air pumping, but I want to make sure I am going about this the right way. Also, has anyone used salt water? I heard that this may help with gains.

Thanks!