The old ball valve is about half way open so I have plenty of room to turn it up if the flow goes to low. Also I have a maxijet mod in the tank so I'm not to concerned about lack of flow. I have a small jg valve to use for the reactor line. I figure the UV will need the most flow so I can adjust that at the tee-ball valve. The other connections require less flow so they should be o.k. pulling water away from the u.v.