# Best ATO?



## Conort2 (19 Jun 2021)

Hi all,

new tank seems to be losing quite a lot water due to evaporation. Can anyone recommend a decent auto top off that isn’t silly money.

cheers


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## Zeus. (19 Jun 2021)

@Andrew Butler did have some for ssle and think they was pretty top notch at a good price


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## Aqua360 (19 Jun 2021)

D-D ATO is £70, which is probably the best price for its reliability


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## X3NiTH (19 Jun 2021)

I’d second the D-D Smart ATO, seems to do the job ok as long as where it is placed the water level is uniform and non variable in the short term, skimmer burping in my return part of the sump was enough to trigger it, once the skimmer was moved and tuned as to not burp the level stabilised and the ATO has been working fine. TUNZE ATO is the most robust, bells and whistles, you get what you pay for.


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## Andrew Butler (20 Jun 2021)

Mine are long gone but thanks @Zeus. 

From my experience and knowledge of this side of things.............

Auto Aqua - who make the h2ocean compact auto top-up (repackaged and sold by D-D in the UK) make/used to make a model called the AutoAqua Smart ATO Micro which is still around,   D-D got the UK rights to those a few years ago too so prices went up.
The 'Smart ATO Micro' uses a blue light to indicate it's on, has a smaller sensor but was only single optical. I think this one is being pushed out of the market and can only assume it's due to the other version and some of their new products becoming available, although strangely the price for this went up when the lite came out.

I've owned both and never had a problem, I was one of the most weary after going bells and whistles with the Tunze Osmolator with my old marine, this has both optical and float but unless you have a sump this would never fit.

The 'h2ocean compact auto top-up' has a bigger/chunkier sensor but also has dual optical sensors, the light on this one is green.

If you're willing to wait a little while or even just buy it without the D-D repackage then the 'h2ocean compact auto top-up' you will be able to get from ebay without lining the pockets of D-D but just under the name of Auto Aqua smart ATO lite - I assure you it's exactly the same product but take a look at the links below to see for yourself.





						H2Ocean Compact Auto Top-Up | D-D The Aquarium Solution
					






					www.theaquariumsolution.com
				








						AUTOAQUA
					






					www.autoaqua.com.tw
				




It was the only thing I could find to keep a minimal rim-waterline after ages looking and several worked for me without fault.
Keep the sensors clean is something I would point out as important and removing limescale and scum from time to time is a must if you want this to last and most of all be reliable.


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## Conort2 (20 Jun 2021)

Thanks for the suggestions everyone, looks like the DD unit may be my best bet. Is the only issue with the tunze system it’s size? As it seems like a pretty fail safe system.


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## Andrew Butler (20 Jun 2021)

Conort2 said:


> Thanks for the suggestions everyone, looks like the DD unit may be my best bet. Is the only issue with the tunze system it’s size? As it seems like a pretty fail safe system.


Are you trying to use it in a display or sump?
How far down from the rim do you have your water level.

With the Auto Aqua unit you can gently bend the cable straight out of the top of the sensor and achieve a 10mm rim to waterline. I would look at getting some rare earth neodymium magnets to use with this sensor if you're going anything over 6mm, just to make sure it stays in place - they're not expensive but watch out as they are very strong!

The Tunze Osmolator relies on a much larger rim to waterline, I'm unsure what that is as I used it in my sump which was 150-200mm down from the rim.





						Osmolator® - Tunze
					

Hi-Tech für Aquaristik




					www.tunze.com
				





			https://www.tunze.com/fileadmin/gebrauchsanleitungen/x3155.8888.pdf


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## Conort2 (20 Jun 2021)

Andrew Butler said:


> Are you trying to use it in a display or sump?


Would be using it in a display, distance from rim to water line would be approximately 30mm.


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## Andrew Butler (20 Jun 2021)

Conort2 said:


> Would be using it in a display, distance from rim to water line would be approximately 30mm.


From memory you wouldn't be able to use the Tunze for this, I did have mine around 7-8 years ago though.
I don't know whether they've modified the design so probably worth looking into though, somewhere like ultimatereef.net might be a good resource of people more familiar with the product.

Personally I think the AutoAqua ones are great and have had 3 running in the house at once without them ever going wrong, mostly the single optical sensor but the dual sensor model can only be more reliable if anything, I would think. I was very sceptical about using an optical only sensor but was the only way I could find to get anywhere near the minimal rim-waterline using trusted sources.


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## X3NiTH (20 Jun 2021)

Conort2 said:


> Would be using it in a display, distance from rim to water line would be approximately 30mm.



Get the D-D ATO for in tank, it’s sleek and modern and wouldn’t look out of place in a show tank, the TUNZE is old school with a bit of new added and a carbuncle for a controller (robust) not inconspicuous and really needs placing in a sump.

By the way, If you need tank overfill prevention then the D-D Skimmer Guardian controller looks almost identical to their ATO, I have it on one of my marine tanks to prevent the tank flooding over (it’s a signature600 and it only has one outlet) if I get a siphon break after stopping the main return pump, it takes a few start stop cycles to get the siphon right on this tank, that’s ok if I’m there to catch it but if there’s a power cut and I’m out it’s a guaranteed flood without the Guardian.


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## X3NiTH (20 Jun 2021)

If you need pics, measurements or more info on the latest TUNZE ATO unit then I have one still in its box that’s eventually going on my EA900 Marine.


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