<a href=showthread.php?s=&postid=10613555#post10613555 target=_blank>Originally posted</a> by melev
Joe, it seems plausible that if all the planets aligned perfectly, the RO/DI would be running non-stop while the sump or plumbing leaked just enough water to stay within the float switch ranges. If that occured, salinity would plummet.
See that's what I get for not going into more of the automation that is being set up.
Here are a few things I left out.
When the lower float trips on the sump my main circulation pump will shut down. The AC3 will keep it off for 30 minutes, before turning things on again. This allows me time see what is happening or to get home if I am local. Or get in touch with the person watching the tank. An alarm in the house sounds and I get a page when this happens, so I will know about it right away.
I also have a water sensor hooked into a dry contact that will be placed on the floor. My floor is pitched a little so anytime more than a gallon of water is spilled anyplace near the tank, it always goes to one spot, that is where the water sensor will be placed. The event that triggers when the water sensor trips is this: Power is shut to the main water supply cutting of the RO/DI from making any more water. Top-off pump is turned off to prevent any water going into the sump. An alarm goes off and I get paged. If it is a leak in the plumbing, the water will eventually lower and the main pump will shut off.
The top-off pump goes through a Kalk reactor as well as about 20 feet of airline tubing and a john guest check valve to prevent the kalk from back siphoning into the ro/do water. That extra head pressure means that it takes about 4 hours to fill the sump about halfway. The change in salinity from that is pretty much nothing. I am lucky in that I have my father, a brother, his wife and a sister-in-law within 2 miles of my house. I also have the home and cell numbers of about 5 reef friends who I could count on to get to my house if I had a problem.
The one thing I'm actually not worried about is not knowing that there is a problem. My last tank tripped a lot, as I had things set up with very low tolerances. Actually the best alarm on the tank that actually alerted me to most of my real problems was my pH alarm. I wrote earlier all my top-off goes though my kalk reactor. Now to prevent too much kalk going into the tank and spiking my pH, I have the AC3 set to trip at a pH of 8.5, At 8.5 the alarm trips and I get a page the AC3 shuts off the top off until the pH get below 8.45. IME my pH will spike before my SG goes down. So this is another indicator that something is wrong.
For me that about as safe I can imagine. My last tank was up for 5 years. The only time I had floods were do to using vinyl tubing on some of my returns. After I re plumbed the setup to make everything hard plumbed with PVC I never had any problems again. The only other time I had a problem was when I didn't put my skimmer back together correctly and leaked water from a fitting. I put the skimmer over the sump this time so that if that happened the water will just go back into the sump. It's also the reason I put a lip and siliconed it down around the edge of the equipment stands, so that if water ever does leak it will be channeled to the front of the stand so that it will fall right where I have the water sensor placed.
I've spent a lot of time with automation over the past 4 years. At this point, I trust it more than I trust myself. I would have killed my tank about a dozen times if it wasn't for my automation kicking in and alerting me to a problem. I had a nasty habit of forgetting to turn on my heaters after doing a water change in the winter time, at least 8 times I have been woken up at 4 AM because the temp fell 2d below the set temperature. I have plugged my top-off pump directly into the wall to pump out water for something then when I turn the valve off for the hose I forget to plug it back into the controller and start pumping water into the sump. Don't know about it until the alarm trips again. And at least 3-4 other things I have done that would have caused big problems if the automation hadn't caught. As I said some people don't trust it, but IME it has a better chance of saving my tank than I do.
wow that was a lot of writing
