Here is the run down:
What drives me here is total and complete paranoia of a flood. If you see a flaw let me know and I will address it and/or fix it. I think that it is bullet proof, but just in case.....
Parts:
3 30 gallon trash cans from Lowe's or maybe BJs--they cost about $15 each
1 pump
1 solenoid valve
2 kent marine float valves
4 bulkheads
10-20' of flexible hosing
1 timer
1 RO/DI system (maybe optional)
10-20' of 1/4 flexible pressure rated tubing
1. Fresh water: This is the automated part of the system. The water flows through a solenoid valve though the RO/DI system, then to the fresh water tank. The solenoid valve is connected to an electronic float switch in the fresh water tank. The electronic float switch has been fixed in place with a bulkhead fitting and some PCV fittings. I did not label the pump but it is the square box between the two lower cans. The pump is on a digital timer that turns on 5 minutes daily to refill to the top system. When the water in the the lower can lowers the electonic float switch opens to the RO/DI system. Notice: I have the water enter the fresh water can through a float switch just in case the solenoid gets stuck in the open position. This will keep the lower container from ever overflowing. I like turning on the pump daily so that the RO/DI system turns on for extended periods of time and is not constantly turning on and off. I collect about 4-5 gallons of water per day.
2. Gravity feed can: This can is fitted with a bulkhead and standpipe. Since the pump turns on for 5 minutes daily, I would overflow the gravity feed system very easily if the evaporation rate did not equal the fill up rate. Therefore the standpipe. When the top tank is full, water will just flow back to the frsh water tank in a loop fashion. The pump would be on for 15 minutes and it would not matter. The bottom of the gravity feed can is outfitted with a bulkhead that is reduced down to 1/4" tubing. This tube leads to the float valve in the sump.
Note: during normal operation the ball valve on the lower right is open and the left one is closed.
3. Salt water can: All this can has is a bulkhead fitting in the bottom and is connected to the fresh water can through a ball valve followed by a T. Normally this ball valve is in the closed position. There are two ways to fill up the salt water can. Firstly, open both ball valves and the water will equalize. The RO/DI system will stay on until both cans are full. Or keep the left ball valve closed and pump the water from the fresh to the salt. Since the fresh and salt are the same size, you can never overfill the salt--unless there is already water in it.
To make up salt water: Fill up the saltwater can. Move the plastic flexible line (from the pump) from the gravity feed can to the salt water can. Close off the ball valve to the fresh water (right) and open the left ball vavle. Turn on the pump and add salt. You now have a closed loop for the salt water make up. Leaving the pump on for a few hours warms the water up to 80F and makes the water homogeneous and warm.
I siphon water out of the bucket in my sump (where all the water returns from the overflows). At the same time I pump water back into the main sump.
The only failure point of the system is the float valve in the sump. If this failed, then I could endup with an extra 20 gallons of fresh water in the sump. But the more water that enters the sump, the more pressure will be on the float valve.
Final notes: Have had this system in operation in one form or another for 4+ years. In my old system, I did not have the ability to drain water from the gravity feed system back to the fresh water system. This led to numerous overflows. The can-over-can with standpip approach has been in operation since I moved over two years ago.
Hopefully this helps some one.
Just some less random thoughts.
ken
