How to automatic mixing water

[wolf_bluejay]

Originally Posted by golf nut

Different manufactures have different method of producing salt, some will give you a pail of 200 white ping pong balls with 2 red ones 4 blue ones and 3 green ones, when all mixed you will have the correct proportions, but mixing in small batches could become problematic. I believe Tropic Marin has a method to give a perfect mix no mater how small a scoop you chose to mix.
I think Farley proved that doing daily changes was just as effective as mass changes, too much math involved for me to want to figure that one out.

Now all we have to figure out is the cheapest method of removing and exchanging a known quantity and put it on a timer to get the correct daily amount no matter what size tank you have.

The more and more I think about it -- the more I'm convinced mixing large quantities at a time is better.

If you used a tall poly container 150-200 gal wouldn't take up much space, and I don't think you would need a large RO/DI reservoir anymore. Most people keep large amounts of RO water on hand for "emergencies", but having 200 gal of ready to go salt water I think would be even better.

As for testing -- I don't test my mixed water change water for anything other than specific gravity, as testing 25 gals at a time for alk, calcium, magnesium, etc would just be to much cost and a pain. But mixing 200 and testing it all at once would give a nice consistent result and would be easy to add calcium and buffer as needed.


As for the pumping -- I think that doing this with logic would be much easier than dealing with 2 pumps that you will never, ever get to be a perfect match without spending silly amounts of money.

For those than can follow controller logic:

1) pump in 2 gals, roughly
2) measure sality


repeat until just right (

if low -- do nothing and wait for some evaporation
if high add fresh slowly,

if just right -- pump out 2 gals, roughly

Basically, you remove some water and have 2 different "top-up" tanks, one salt and one fresh. Mix both to get things just right all the time, instead of having only a fresh water top-off.


If you get the mixing of the salt and fresh right on the controller, your change volume is controlled by how long you run the pump, and the system will "top-off" with the right mix of salt and fresh to re-fill the tank.