Russ, I wanted to clarify something. I use a garden nozzle to apply/rinse, so I don't have to change anything but a valve at the pump to rinse with fresh water. I run two garden hoses into my pump for a fresh water supply. I have tested the flows off houses all over Tallahassee, most "in town" homes flow about 8gpms on one hose and about 12gpms on two hoses. Because my pump raises the pressure it allows me to rinse with that good flow at 200-300ft of hose. I hope this makes more sense. I have done a lot of real tests to see what works best for me. Flow, Flow, Flow with some moderate pressure, never more than 150 for roofs & houses.
That's a good way to do it, since you already have the hoses out for watering during the process anyway!
I saw one inexperienced roof cleaner working alone.
He had a garden hose filling a rinse tank, while he was up spraying.
Stuff was running down off the roof.
He just kept on cleaning, got done, and started to rinse.
3 days later, death was everywhere.
The mix kills plants two ways.
By celluar degeneration, and by sodium poisoning.
The cellular degeneration is caused by contact with the chlorine, and is prevented by tarping/watering the plants.
Sodium poisoning is cured by dilution.
Dilution is the solution.
You always have Two issues when rinsing.
The first is to get the leftover mix off the roof, in case of a light rain afterwards.
The second is to make sure that the rinsed mix is also rinsed well down past the root line of the plants.
This means that once the roof is rinsed, another rinse trip along each side of the house is a good idea.
You can never rinse "too well", but you can easily rinse "not good enough".
A "quickie" rinse can sometimes do more harm then good.