Tunze Osmolator 3 for Tank Water Level Control
In my last tank, I used a large float switch (Omega Engineering LV-1201, still sold, bottom example in this picture):
Coupled with that, I used a slow diaphragm pump to deliver kalkwasser (a Reef Filler, no longer sold). There was no other limit on delivery besides the float and the slowness of the pump. But the system worked well for 20 years and I considered reusing the float switches.
This time around, I'm not dosing kalkwasser (due mostly to space limitations in my fish room), which can open up the types of devices used. I still have the switches, but not the reef filler. I made the decision that I wanted better control on potential overfill than I had before. The osmolator also allows me to easily change the desired water level in my sump (by moving the magnetically held sensor up or down) without having to relocate the float switch which would require drilling new holes in the can and capping the old one.
For that reason, I opted for the Tunze Osmolator 3. One of my concerns with it that I have posted in the past is the relatively fast pump provided with it. I was actually surprised when I opened the package how small it actually is since pictures don't show that. Nevertheless, that doesn't change the flow rate (two settings, 70 or 112 L/h, depends also on head pressure, the faster rate also comes with a higher maximum head pressure), and the flow rate concerned me from an overfilling perspective. If something went awry, it could overflow my sump in an hour.
Well, in setting up my system, I had collected a lot of tap water in my new salt water trash cans in case I needed it before my RO/DI arrived. When I ended up not needing it, I figured the pump of the osmolator 3 would be able to quickly pump it to a drain. Wrong lol
First lesson: the osmolator 3 has a time out feature to prevent overflow situations if something goes drastically wrong or the tank is leaking somewhere, flooding it with fresh water. I was not previously aware of this feature. The timeout is 10 minutes, and only a manual reset can restart it. If the pump is called for constantly for more than 10 minutes, it shuts down until you reset it (by power cycling it). That greatly alleviates the concerns about overfilling (the limit for a single delivery cannot exceed about 12 L (3 gallons), which cannot overflow my sump. Good for tank use, but it made my use of it to empty 80 gallons of tap water from my Brute cans a slow process of resets. I finally gave up and got a different pump. lol
The osmolator itself has two sensors in a single sensor "device" and so also has an internal limitation on delivery. The Primary is based on infrared and one (Tunze calls this the safety sensor) is based on heat conduction. Both must see a need for water to allow water flow.
OK, so there are three ways the pumping is limited and controlled. I have it hooked up now and it is operating fine. One immediate advantage over my old one is that the rock and sand will be delivered at two times, and each will result in a large change in system volume. I have the water level in my last Brute can set very low to allow the sudden volume increase in a week when the first rock arrives. After that, I will want a higher level until I remove some water to allow the next rock delivery. Then low again and then finally where I ultimately want it higher. Yes, that's a one time situation, but it shows when a movable water level in the sump is desirable.
I'll comment more on it in the future as I have more experience with it. As folks will recall from the first post of this thread, Tunze provided it to me free of charge, and some may assume that clouds my comments. I won't be able to convince everyone otherwise, but I assure folks it does not. If something deviates from expectation, I will certainly tell folks.
For now, I am quite happy with it. :)
