Why do people buy expensive ATO?

[subodhs]

So, this might just prove how clueless I am, but I have to ask: Why are people shelling out $200, $300, or more for Auto Top-Off (ATO) systems? A quick search at BRS shows all the popular options: Smart ATO, ATO+, and a bunch of other fancy-sounding names. But at their core, these are just level sensors, a water pump, and maybe a leak sensor. Sometimes, two sensors.

Yet, they still don’t include a salinity sensor, or any "smart" feature to differentiate between topping off with RO or saltwater. You’re still manually ensuring your freshly made saltwater is at 1.026. So, what exactly are we paying for? Is it the marketing? The sleek design? The peace of mind? Snake oil?

Before you roast me, let me explain my setup. I’ve got a continuous automatic water change hooked up to my Apex. My salinity probe decides whether the top-off should use RO or saltwater to maintain levels within hi/lo sensor ranges. It’s been running flawlessly -- 2 years on my current tank and 5 years on my previous build—and it keeps salinity in check (within reason). Sure, I keep an eye on the salinity probe for bubbles and occasional recalibrations, but it’s been reliable and low-maintenance.



Pictures for proof:

And programming is quite simple literally:

So, seriously, what am I missing? Is there some magic feature I’m overlooking? Or is it just my approach that’s a bit “DIY unconventional”? Feel free to call me daft I’m genuinely curious what makes these systems worth the price for so many reefers.

 

[Twocorns]

No idea. I still use a sensor of some sort, aqua lifter and 5 gallon bucket as my ato.

 

[Randy Holmes-Farley]

I used a different but still expensive diy for ATO. I used a high end float switch and a slow pump to deliver kalkwasser that way.

I’d be wary of using automatic salinity control to dose even fresh water and especially not kalkwasser. I’ve just seen too many issues with controller measurement of salinity to allow it to decide to dump water into my tank.

Still, you spent big money on a controller, and I did not, so my system is less expensive.

 

[JonoH]

To be honest...your set up looks way more complicated than any standard ATO's avaliable.

Remember these are designed to be stand alone - ie...tanks that are not running a controller like an APEX which is unaffordable to a lot of reefers.

 

[FUNGI]

$20 used JBJ and a $5 5 gallon container from Target. Used MJ1200 ($10.00).....
5 years and still going strong

 

[JTP424]

Sounds like a solid system.

Let's break it down! As a comparison to my ato.

You say you're using an apex, sooo let's throw $600 for a used one.
I don't use an apex. But needed an Ato. So I paid $200 for an ato.

If I had an apex system, I would potentially look into a similar set up. Digging deeper still... you mention RO or saltwater. So now two Buckets of water rather than a single. I barely have space for one!

Additionally I prefer to buy/use specifically built items. No diy etc unless broken etc. So this answers the ease of use.

Essentially you answer your own question

Cost/overall need. Size/space limitations. Personal knowledge/diy ability.

You created a solution that fits your need nice product!

 

[iReefer12]

I will die on this hill. @AVAST Marine makes the best ATO sensor out there. Had it 14 years, on a 30 gallon biocube, and now on a 700 gallon monster tank. It always works like a charm and gives me piece of mind.

Salinity probes are next to useless IMO, no way you can actually rely on it on a consistent basis.

 

[rtparty]

Your system looks awesome and has worked great it seems. I would NEVER trust my tank to a salinity probe let alone the Neptune salinity probe.

If you need to add saltwater to fix salinity, you have some other issues going on IMO. Once set, salinity shouldn't change much and you should catch it with weekly testing or weekly water changes. Daily AWC may change the scenario though as I wouldn't ever use that either. Too much automation is a recipe for disaster even with redundancy built in at every level.

I used a cheap ATO once. American company that just rebrands Chinese stuff. The magnet exploded and filled my sump with rust, metals, and anything else in there.

I use TUNZE because I want quality and reliability on such a vital piece of equipment.

 

[BeanAnimal]

Let me describe my setup.

Total system volume ~125 gallons @ 35 PSU

ATO holds 5 Gallons and is filled by RO/DO automation when empty.

ATO feeds tank via a float valve.

Float switch in Tank serves as fail-safe and shuts down RO/DI production, which limits a stuck float valve to max 5 gallons of RO/DI dumped into the tank. So worst case scenario, stuck float equates to about 34 PSU.

************************

GHL Maxi Doser

30 Gallon NSW reservoir at around 35 PSU (I don't monitor it closely or care).

500 ml per day pumped (50 ml 10x per day) into the display.

***************************

No fancy monitoring or logic based "NSW or DI" dosing going in. Just the float that adds RO/DI when water drops do to evaporation OR sometimes automated testing and the dosing pump pushing in 500ml of saltwater per day.

Skimmer takes water out and automated testing takes water out, as does evaporation. I don't bother timing the saltwater additions or controlling the top-off of RO/DI. I have run this way for well over a year and my salinity is pretty much dead stable. If I have to pull 5L or more of water out, say to acclimate corals, I just tell the doser to add ~5L of NSW. I don't measure closely or worry about the ATO filling the sump as I pull water it.

In the end it all comes out in the wash and adjustments are extremely rare.

 

[subodhs]

Sounds like a solid system.

Let's break it down! As a comparison to my ato.

You say you're using an apex, sooo let's throw $600 for a used one.
I don't use an apex. But needed an Ato. So I paid $200 for an ato.

If I had an apex system, I would potentially look into a similar set up. Digging deeper still... you mention RO or saltwater. So now two Buckets of water rather than a single. I barely have space for one!

Additionally I prefer to buy/use specifically built items. No diy etc unless broken etc. So this answers the ease of use.

Essentially you answer your own question

Cost/overall need. Size/space limitations. Personal knowledge/diy ability.

You created a solution that fits your need nice product!

My buckets are the big giant trash cans . They sit outside, way far away from the aquarium. The lines run to the DOS pumps over 70 feet away. Here's a picture of the hi-tech setup :

I know some folks wouldn't trust a Neptune probe but I've got other safeguards like regular testing at 2 days, weekly testing, calibration checks, programmatic guard rails and stuff. But my point was, why are these expensive ATO systems completely ignoring salinity monitoring? I keep my salt water levels at like 40 ppm or something coz I make the saltwater once in 2 weeks and teh DIY system takes what it needs. Automatic kalkwasser dosing and things in between are accounted for as well in the mini lab

 

[Mayor583]

No idea. I still use a sensor of some sort, aqua lifter and 5 gallon bucket as my ato.

I'm slowly getting back into reefing. My 90 gallon has been running fine these last few weeks with manual top offs done by me.

As I'm shopping for an auto top off system, I'm amazed by how expensive the reservoirs are for these things. I am curious if you could elaborate on your setup a bit. I'm hoping to set up an ATO before we go on vacation and am open to some ideas.

 

[subodhs]

I used a different but still expensive diy for ATO. I used a high end float switch and a slow pump to deliver kalkwasser that way.

I’d be wary of using automatic salinity control to dose even fresh water and especially not kalkwasser. I’ve just seen too many issues with controller measurement of salinity to allow it to decide to dump water into my tank.

Still, you spent big money on a controller, and I did not, so my system is less expensive.

@Randy Holmes-Farley I completely agree—it's not a small investment, and the reliability of probes or measurements can be tricky. In fact I'm questioning the reliability of Apex itself sometimes. But, over time, I’ve had to put guardrails in place to account for issues like bubbles or calibration drift. My point is more about the value proposition of those $200+ ATO systems. At the end of the day, they’re essentially a pump and some sensors with a "smart" name slapped on them. Where’s the real deal with these expensive systems? Am I missing something here?

 

[Reefer Matt]

I use a bucket and float switch for two tanks, and dosers for three others. People spend a lot of money for different reasons. Such as, they thought they had to, they thought it was a good deal, or they simply want expensive things. This is a hobby of luxury, not necessity. The sky’s the limit, but a handy person can do it for much less.

 

[subodhs]

I'm slowly getting back into reefing. My 90 gallon has been running fine these last few weeks with manual top offs done by me.

As I'm shopping for an auto top off system, I'm amazed by how expensive the reservoirs are for these things. I am curious if you could elaborate on your setup a bit. I'm hoping to set up an ATO before we go on vacation and am open to some ideas.

I'm guessing you meant to know @Twocorns 's setup? Coz I'd love to explain my setup, if anyone's interested lol

 

[ChiCity]

personally,
i’d be more worried
about the reliability
of your
red sea tank…

 

[subodhs]

I use a bucket and float switch for two tanks, and dosers for three others. People spend a lot of money for different reasons. Such as, they thought they had to, they thought it was a good deal, or they simply want expensive things. This is a hobby of luxury, not necessity. The sky’s the limit, but a handy person can do it for much less.

Exactly! You've captured more truths in those sentences than years of experimentation ever could. And I completely agree—a basic float switch is often far more reliable than those optical sensors. Ask me how I know.

This really is a hobby of luxury, and that explains a lot.

 

[subodhs]

personally,
i’d be more worried
about the reliability
of your
red sea tank…

I know. I'm worried about it. And it still stumps me that @Gumbies R Us (and many others) was trying to tell me, I just had no idea what he/them was/were talking about until it was too late *crying*

 

[thedon986]

Because my Tunze ATO has been proven more reliable than an overpriced salinity probe. I would never trust a salinity probe as an ATO.

 

[JayM]

I will die on this hill. @AVAST Marine makes the best ATO sensor out there. Had it 14 years, on a 30 gallon biocube, and now on a 700 gallon monster tank. It always works like a charm and gives me piece of mind.

Salinity probes are next to useless IMO, no way you can actually rely on it on a consistent basis.

Not saying they do or don't make a great sensor as I've never used one, but your 14 year old sensor may be far superior than what they're producing today. Or it may be that their sensors are the same now as they were then.

 

[Randy Holmes-Farley]

. But my point was, why are these expensive ATO systems completely ignoring salinity monitoring?

Unless you are using a two part, salinity hardly changes at all.

I can only say why I “ignore it”: because I consider it a bad risk reward decision. Why risk a problem to fix a non problem?