Sammy, why not a water treatment dealer for testing? Do you think their accuracy is less than a lab? Especially for "orangish bacteria".
I do not sell or suggest using solution feeders. They are a PIA type thing and rarely dose the same strength solution because of it weakening in the tank as soon as you mix it. And anyone thinking of buying water treatment equipment should think of buying online unless they want or need to depend on a local dealer. If they don't want to install it themselves, they can hire plumber to do it.
In this case, we need to know what the orange bacteria is. It sounds like IRB; iron reducing bacteria. Is this water from a residential well? If not they should call the water company. If it is, and there is enough of it to cause a problem, it has to be killed. Filtering will cause more of it so have them remove the Nylon filter thing.
Is there an odor to their water? If so is it in the hot and cold or just the hot? If in the hot only, turn the temp up to 140* for a few hours. That will kill the bacteria that live in the water heater and cause the odor. Or replace the anode rod with a different type like aluminum. Check their toilet tanks for a clear to orangish brown slime at and below the water line. If present, that is IRB. If there is an oily film on the water, that is manganese reducing bacteria (MRB).
I suggest an inline erosion chlorine pellet chlorinator followed by a special mixing tank and then a backwashed filter with a special carbon. That system usually costs the least of any and the chlorinator is nonelectric, and has no moving parts and maintenance is like every 2-4 months depending on how much water is used. It takes like 20-30 minutes to clean the hopper and add more pellets.