Running fresh water intsead of seawater through the AC units.

Where are you going to get the fresh water? Most marinas who’ll kick you out if they catch you ….

Two different ac techs ( good ones I trust) recommended not using bromine tablets.

instead I set up a valve system so I can back flush the coils with fresh water. In winter I back flush every 4-6 weeks… in summer every 1-2 weeks. Takes me less than 5 minutes for each chiller.

also, have South Bay strainers (external strainer) completely eliminate the need to clean the internal strainer or eliminates the internal strainer altogether.

While on our own first dock up Trout River, Jax, (over 15 years ago) I was going to shoot another shallow well down, just for some of the boats ACs.
Never got to it and we moved back to Ortega.

I do remember one hot summer in Ortega. Grass, barnacles, carpet grew over night in/on everybody's hulls & AC plumbing.
Was a bad movie come to life what was growing in that dark hot water.
I remember our diver talking about Berber carpet on the boat bottoms.

Then we had a AC water pump failure.
It was amazing what water options are readily available in the depths of an old Bertram hull.
We were the only cold boat on that river for a while. Yes, some ACs can work on dock water.
Now that I have told my only closest friends, you can't tell anybody.

Then, we finally moved up (StJohns) river a few years ago.
We have been blessed with our new up river location. Calm & cool spring water.
No fouling and AC's run very well with cool fresh water going thru them.
Thought I could rub that in to my close friends also.

I have a 3/4 full port ball valve on the pump outlet and a tee above that with a valve on the bench side that I connect to a garden hose. When I want to run fresh water through the system I close the lower valve and open the fresh water valve. Simple system that works fine for me.

This is confusing. If you have a non regulated fresh water supply there are valves to be manipulated; manually or automatically.
I used a Red Hat 230VAc solenoid valve controlled by the pump relay. So the shore water was injected into the system vs the raw water pump turning on.
If you have X fresh water flowing to your boat, valves and switches can be installed to make it work.
The issue; thru 1/2 or 3/4", X supply may not flow enough for max BTU.
Then high head pressures.
In my post, was only able to run some ACs.

Paying for 60 USG a day of usage at the dock is one thing… paying for 40 GPM is another.

if you can’t figure out in 20 seconds how to hook up a tee and valve into your system…. Especially when you could not even bother giving us any info about the boat, number and type of units… do you really expect any intelligent answer?

garbage in, garbage out.