My semi-auto water change setup.
I decided to build a semi-auto water change setup. For safety I did not want to make it fully automatic but it is close.
Pros of Fully Auto Water Changes
1. Can be completed while I am on vacation
2. Keep parameters rock solid and ensure that they actually get done
Cons
1. Requires a very expensive setup; 2 dosing pumps
2. Calibration of the pumps is difficult when pump flows can change
3. Salinity can change depending on how off the pumps are
Now for the setup and why I chose to do certain things...
First off - this is a picture of the unfinished laundry room. My office/man cave is on the other side of this wall and the tank is directly on the other side. For a while now my top off 14 gallon brute container has been taking up a lot of space on the counter top. Since this is my wife's laundry folding table she has wanted it cleared off of my junk. I still have some more stuff to remove but I believe this is much better than before.
I also didn't like the fact that the 14g brute container held too much water, while I could have just reduced the size of the container I also wanted to clean things up. Now there is a 5 gallon top off bucket with a 1 1/2" hole drilled in the bottom to accommodate a bulkhead. I wanted a 5 gallon bucket because incase something goes wrong with the float valve only 5 gallons will empty into my tank. This is not nearly as bad as 14 gallons.
Each bucket has 1/4" OD tubing coming from it that goes to a ball valve and then to the sump into a "Y" fitting before the float valve. I also use ball valves near the "Y" inside the sump but I will talk about that more below. The salt bucket is filled weekly and is only mixed and heated while mixing for the first day or two. Since my water changes only consist of 2-2.5 Liters daily I do not see any point in heating the water after the salt is mixed well.
I ended up placing ball valves near the "Y" because I was having a backflow issue when both valves were open under the buckets. For instance, if the top off bucket was full and the salt bucket empty and both valves were open then the fresh water would go down to the "Y" and back up to the salt bucket. Pressure would force is up the "salt" tubing. While I could just make sure the salt line was closed I wanted to add another safety feature.
After using this setup for the first time today I realized how easy it is going to be to do water changes now. There is only one problem I did not forsee. The float valve replaces water rather quickly at the beginning but then starts to slow down as the level is equalized. You really need to give the valve time. In my case I had to wait 20 minutes for salt water to completely top off. While this isn't a big deal it is worth noting. JUST DON'T FORGET TO TURN OFF YOUR SALT LINE AND TURN ON YOUR FRESH LINE, LOL!
To automate this a bit more, I plan on adding a dosing pump to pull water out of the tank and push it to the laundry room sink. Since all water taken out is topped off I am not worried about pulling out too much water. I can just set the dosing pump up for so many minutes and leave it then just adjust the va