Once you have your water in the system, you should be able to close the loop and never worry about it again. Each Turbine can use a max of 2000mb/t of steam, which gets turned into water to be shipped back to the Reactor.
I haven't played with it since it was Big Reactors, so it may have changed in updates, but a single Fluid Port was able to move all required fluid at that time. The problem was typically that fluid transport was gated per connection, resulting in the need for multiple ports. This can be avoided by either setting the Turbine and Reactor directly touching, with ports configured and aligned, or using something like Thermal Dynamics Super Laminar Fluiducts, which have no throughput limits.