Some problems to begin with -- resolved now By ShawnCC on 9/28/2011
ShawnCC would recommend this product to a friend
I had some problems with this unit right off the bat...
Firstly, the pump didn't seem to be pumping anything. After several minutes of running (as evidenced by the whining noise), still no water was coming out. The ATO reservoir sits right beside the sump, so it only has to pump a few feet, and with about 14 inches of head. Finally, I primed the line using the age-old sucking technique, and from that point on it seems to be working.
The next, and bigger, problem was that the float switch, which is supposed to be the safety backup, was not working at all. Regardless of whether I lifted it manually or submerged it, no alarms would sound and the ATO kept pumping away. I contacted Roger at Tunze on their support forum at ReefCentral, and he confirmed that the magnets inside the float switch bracket were installed (by the factory) upside down. They are supposed to be at the bottom of the bracket, but these ones were at the top. Becuase the float switch itself operates on magnetic principles, the mis-aligned magnetic field was interfering with the switch, causing it to fail. After a botched attempt at fixing it myself, Roger is sending me a replacement bracket. No hassles--just a simple replacement.
The Osmolator and I still have yet to build a trust relationship. I've decided to plug it into one of my Apex controller's switched outlets, with yet another float switch (monitored by Apex). This way, the Apex can also kill the power to the top off if it detects levels getting too high. Redundancy is key.
The only other gripes I have with it, as other people have mentioned, are that it automatically runs the pump for several seconds when initially powered up (why?) and that the pump itself has a high-pitched shrill whiney sound to it, so it can easily be heard from outside the stand when it's running.
In general, after much manual testing of the optical eye sensor, I would say that it works quite well, and I am pleased with it. The price is hard to swallow, but I rent my apartment and it has hardwood floors, so I'm willing to take all precautions necessary to prevent overflow disasters.
Tunze customer service (Roger) has been very responsive, so in that regard, I give them (him) an A++.
perfect By illya on 7/10/2011
illya would recommend this product to a friend
This is a very nice ATO that keeps the level of water right where you want it. It saves me about 15 min a day at least from manually having to refill my sump, that's a lot of time saved after a while. well worth the cost, quality unit and you can tell a whole lot of thought went into this unit.
Only one flaw By Carol on 7/7/2011
Carol would recommend this product to a friend
Love this system but the only flaw is the pump does not last, after 3 months it starts to drips after pump is off and sometime its a non stop drip. I'm on my 3 pump now and the system is only 9 months old. But other than that its a great ATO sytem, I just keep a extra pump now.
Great product By Craig on 7/2/2011
Craig would recommend this product to a friend
I just ordered my second Osmolator as the control module of my first one just died after 3 years. I didn't consider buying any other ATO system as this thing worked perfectly until it went out. The Osmolator is so precise at maintaining water level which is essential for growing healthy coral.
Awesome auto top off unit. By Dirtman on 4/30/2011
Dirtman would recommend this product to a friend
I like to have my 90 gallon reef tank as full as possible so it took a little time to adjust the over flow shutoff switch to the correct level. Once the sensors were adjusted to the correct height it has worked flawlessly. I'm very pleased with the Tunze 3155 Osmolator. It's worth its weight in gold.
Good but flaws By steven on 4/11/2011
steven wouldn't recommend this product to a friend
This is a good product that works but has some flaws:
1. Every time the unit loses power or is unplugged and plugged in again, it will start pumping water for 10-15 seconds even if you are at the correct level or above.
2. There is an alarm to signial too much water. It's loud and can not be disabled unless you take the unit apart and move a jumper.
3. The eye didn't work correctly out of the box. I had to wet it and rub it with a clean cloth vigorously to get it to function. Once cleaned it worked. I question it's long term reliability.
Kinda wish I went with the JBJ ATO and saved 100 bucks.
excellent product By bblinks on 4/9/2011
bblinks would recommend this product to a friend
Great product, set it and forget it. This product will make your life a lot easier.
Peace of Mind By Tim on 3/27/2011
Tim would recommend this product to a friend
I purchased this product to go with a Kalk stirrer I recently purchased from BRS. I had watched the videos from the knowledgeable staff at BRS. I have to say this auto top off is the best thing I ever purchased for my system. It is extremely easy to set up and you don't have the worry of it over filling since it comes with multiple safety features.
Expensive, but awesome. By Allan on 3/25/2011
Allan would recommend this product to a friend
I was hesitant to buy this, given the premium price, but it keeps my sump level incredibly steady. MUCH better than the upside-down water cooler jug gravity feed setup I had before. The only odd thing about it is that it runs the pump for about 5 seconds or so any time you pull the plug and plug it back in. Not an issue unless you're turning it on and off a lot. Though that could happen if you have it on a controller set to only turn it on for say 5 minutes every hour. Just something to be aware of.
Worth the price ... By Larry on 3/14/2011
Larry would recommend this product to a friend
The Tunze osmolator is not the cheapest ATO, but I think it is the best. Worth the price for piece of mind.
Best money I ever spent!! By Steve on 2/2/2011
Steve would recommend this product to a friend
I cant say how many times I let my ro run into my tank to top it off and forgot about it.this is set it and forget it.I have the pump in a reservoir that has a float switch connected to my ro.Nothing better than having one less thing to do to your tank.Pump is loud though just so you know but the water level is extremely precise.
Awesome By David on 1/6/2011
David would recommend this product to a friend
After having a little trouble getting the osmolator working I emailed Tunze and washed the sensor with soapy water. This thing is awesome. I'm glad I spent the money and bought it over other float switches.