DonW
R.I.P.
After seeing the Dialaseas system a few years ago Ive always want such a set up. With my new tank this is just the ticket. I will have a new camera soon so will get pics up of the new system and this gizmo later. This will be a long drawn out thread explaining the why and how it works as I progress. The first part is the hardest which is salinity control.
Plain water has a specific gravity of 1.0 a horizontal float switch has a specific gravity of .5 which of course is why it floats. All I needed was a float switch that had a specific gravity of 1.025 and another of 1.027. Just like a ato I think its a good Idea to have a high and low limit. Now the hard part where do I find such a switch.
Its simple we just mod an everyday switch. The horizontal float itself is sort of hard foam. Simply drill a #7 hole in the end of the float almost all the way to the pivot point then tap with a 1/4-20 tap. Now just run a stainless set screw with no head into the hole all the way to the bottom. Now cap it off with a nylon screw for a plug.
Mix sw to 35ppt checked with a refract and warmed to the same temp as the tank. With the screw all the way in the float will float at 1.0. Slowly back the stainless screw out 1/4 turn at a time after a few trys the float will start to sink. Once the screw is set just right it will just barely lift off the stop at 35ppt even if its fully submerged which it should be to be accurate.
Now test it out by removing some water and replace it with rodi water, the float will drop to the stop. Now go the other way take out water and add really salty water. As soon as it hits 1.027 it will rise and trigger the magnetic switch. Float switches do not absorb water and will not change so once its set it will stay there. I used a Madison switch for this experiment. For a period from sept 06 to today dec 07 the switch has remained accurate and is controlling two different relays connected to two aqualifters and a auto top off. One has sw and the other rodi water.
This was the biggest hurdle to get over on this project. The next step is how to make sw brine. I'll explain this in the next step.
Don
Plain water has a specific gravity of 1.0 a horizontal float switch has a specific gravity of .5 which of course is why it floats. All I needed was a float switch that had a specific gravity of 1.025 and another of 1.027. Just like a ato I think its a good Idea to have a high and low limit. Now the hard part where do I find such a switch.
Its simple we just mod an everyday switch. The horizontal float itself is sort of hard foam. Simply drill a #7 hole in the end of the float almost all the way to the pivot point then tap with a 1/4-20 tap. Now just run a stainless set screw with no head into the hole all the way to the bottom. Now cap it off with a nylon screw for a plug.
Mix sw to 35ppt checked with a refract and warmed to the same temp as the tank. With the screw all the way in the float will float at 1.0. Slowly back the stainless screw out 1/4 turn at a time after a few trys the float will start to sink. Once the screw is set just right it will just barely lift off the stop at 35ppt even if its fully submerged which it should be to be accurate.
Now test it out by removing some water and replace it with rodi water, the float will drop to the stop. Now go the other way take out water and add really salty water. As soon as it hits 1.027 it will rise and trigger the magnetic switch. Float switches do not absorb water and will not change so once its set it will stay there. I used a Madison switch for this experiment. For a period from sept 06 to today dec 07 the switch has remained accurate and is controlling two different relays connected to two aqualifters and a auto top off. One has sw and the other rodi water.
This was the biggest hurdle to get over on this project. The next step is how to make sw brine. I'll explain this in the next step.
Don
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