JBJ ATO - Anyone have it?

Well, some will claim this, but my float switch ATo requires only 15 ml of water taken from the tank to get the ATO to kick in. that's 15 ml in about 250g of total water, so that is extremely precise. I hear tunze guys saying it only lets the level drop an 1/8" before kicking in. Even witha tiny final sump chamber before the return pump, 1/8" is a lot more than 15 ml in my tank. I don't think there is any argument room on this, if any. If anything the float switch might be more precise.

My profession is a buyer of electronic and industrial components, so i know quite a bit about many switches and sensors.

 

I don't know about precision being relevant with regard to how a Tunze works.

One of the 'features' of the Tunze is that it doesn't just add water back 15ml at a time because that tends to wear a pump out fairly fast. It lets it go enough so the pump runs for at least 10 seconds per run.

I haven't verified 1/8" or anything, but I have verified my SG doesn't fluctuate throughout the day. So I don't think the precision of the optical sensor is really being used to full potential. At least, you can not compare the precision of a Tunze optical sensor as it is designed to not constantly turn your pump on and off. It may very well be capable of detecting a 1ml shift as far as I know.

 

Who knows? I do know that 15 ml of water change in a system around 250g won't be much. So I would assume that SG would remain very stable.

The aqualifter pump is 10 dollars, and mine has run flawlessly for about 2 years now. I don't think that an on off cycle is going to ruin an aqualifter, even over several years. IIRC, my ATO only tells the pump to run once, maybe 2x an hour. And when it does turn on the pump, it has a slight extra amount of run time on the pump after the switch has told the unit that it has enough water again.

I only brought up the 15 ml of water needed to turn the unit on to inform those that assume the tunze is more precise with the optical sensor.

 

So I had to crunch some numbers.....

My osmolator pump will put out 27.7 ml/sec...so 277 ml/10 sec run. Now that sounds about right, cause my ATO kicks in about every hour and that would equal around 1.46 gallons per day. Now I have not timed my ATO or accurately measured daily use... but it is between 1.5-2 gal/day.

So that 10 sec run of 277 ml would equal 2.5 mm in my return section of 18"x6". Sounds about right for a normal top off. The optical sensor is designed to be about 2 mm in and the pump is designed to run for 10 sec.... so while these numbers are not balls on, they are in the ball park.

Now what I don't understand is how a float switch can activate by the loss of 15 ml of water unless it was in a Coke can. It is determined by the travel between the switch being made and not being made and that is quite measurable. And two swiches for on off spaced very close together.... less than a mm would be quite accurate... if not costantly turning on and off continuously. So that length of travel spread over what ever container it is attached to will equal the water volume that it actuates.

Not I'm not going to say that the Tunze is the most sensitive...seems that with any ATO it can be set up to top off very little amounts attached to small or large compartments and that any ATO will keep a very stable salinity through out the day..... I'm just having a hard time with a 15 ml activation over a 250g system.

Even on my system, my Tunze will top off 277 ml a shot..... that is 277 ml added to 416,395 ml of volume which is 1/1503 of total volume. Needless to say salinity will probably be effected out to 3 or 4 decimal places.

 

My return pump area of my sump, where the float switches are, is not huge by any means, but quite a bit bigger than a coke can.

Off the top of my head, it is 12" tall, by 5-6" long, and it is a 75g aga tank so 18" deep.