DaS Energy
Member
Hello Tom,
To answer your question "Is it possible to have something that detects when the tank is empty and then switch to town water" the plumbing device you need is a stocp cok and ball. However in place of fitting to the top of your tank you fit it down low. It makes no difference that it shall also stop the tank from filling as town water is constantly coming in. Which is shut off by the stop cock when the tank recieves rain water.
Cheers Peter
saferain
Member
Diver,for wet systems of course the "flushing velocity" will never be enough to flush the remaining organic matter. What matters to the user most is, is it drinkable?
The decaying organic matter is already there in the pipe.
Sometimes, it goes through a cycle of aerobic(when it rains) and anerobic decay (when it sits until all the oxygen is consumed).
An intermittent drizzle (let,say 0.1 mm over 2 hours) will not do much to clean a
roof. And it will not displace the tainted stagnant water.
But, what it will do is reoxygenate that water such as to alter the balance between
anerobic and aerobic.
Let's assume you have a wet system on level ground without a "pig"(drainage trench).
And you have organic roof issues such that degradation of such may/can/has
caused taste/odour concerns.
You cannot avoid these materials entering your lowest point.
These materials eventually rot and are continually replaced.
Who cares, as long as the water tastes good?
Which is why I take gentle issue with Diver and defend the practice
of installing a FFD high on the riser.
Yes, it will not flush out all the stuff from a wet system.
But, it will, (correctly "sized" or "set") make that water drinkable.
Most of the time.
