I have had some questions as to how my auto water change system works. Here is a picture and details for those that are interested. If you have any other questions, please feel free to ask.
If you would like to see a complete description with photos and a plumbing schematic of my Water Change System, you can look
Here .
The water change system is fed from a line off of my closed loop pump on the frag tank, and free flows into a 29 gallon fuge which then free flows into the frag tank.
I run one barrel with the system. The other barrel is closed off with the ball valves. When it is time for the water change, I close the barrel that is open, then open the barrel that was closed; the water change is done. To empty the old water, I open another valve piped into the bottom of the barrel and use a pump and garden hose to pump the barrel empty. The barrel is then refilled by opening a valve from the RODI unit. There is a Kent Float Valve in each barrel to keep it from overflowing during the refill (be sure to put the float valve lower than the discharge bulkhead). In a day or two I go back, shut off the RODI valve and put in the salt (be sure to shut off the RODI valve).
I have a maxi jet in both barrels to plug in for the one that is not running with the system. The one that is not in use with the system is just like having your bucket of salt water ready to do a water change. In the other barrel the water is constantly moving from the water being pumped into the bottom from the frag tank closed loop (kind of like water being pumped into your display from a sump). Then it overflows from the bulkhead in the top of the barrel, into the fuge, then free flows from another bulkhead back into the frag tank (kind of like and overflow box in the display tank, but there is no siphon to break).
I only have one barrel on line at a time. When I want to do a water change I switch barrels. The barrel just stays ready and full of clean saltwater until I decide to chance barrels (in other words, do a water change). The water change is preformed by opening and closing valves.
The set up works great and I love it.
This image shows the feed line that feeds the barrels from the closed loop pump in the frag tank, and all the valves with a description of their function. The water enters the bottom of the barrel and exits the top of the barrel. In this picture, barrel 1 is in use and barrel 2 has fresh unused salt water.
<img src="http://www.high-velocity.org/saltcity/album_pic.php?pic_id=458"><br><br>