Kessil

Evaporation is no joke.

Srt4eric

Supporting Member
So with my biocube I guess I was lucky. I had no idea how big a deal evaporation was. Now that the 40 is starting to cycle I'm noticing the water level in the sump dropping daily and salinity going up and up. I do have an ro/di system to replenish the water but what I really want/need is an A.T.O. system. Can anyone recommend and decent cheapish ato? Anyone have one for sale they want to get rid of?
 

max_nano

Supporting Member
Smart ATO micro has served me well. It alarms if it has to fill more often than normal (not sure how this little device has memory like that but it works!)

also I use a petco 10 gal which is a great ATO reservoir option for under $20
 

RandyC

Supporting Member
So with my biocube I guess I was lucky. I had no idea how big a deal evaporation was. Now that the 40 is starting to cycle I'm noticing the water level in the sump dropping daily and salinity going up and up. I do have an ro/di system to replenish the water but what I really want/need is an A.T.O. system. Can anyone recommend and decent cheapish ato? Anyone have one for sale they want to get rid of?
Did your biocube have a lid? If so, that'll make a huge difference in the amount of water you need to replace due to evaporation.
 

Srt4eric

Supporting Member
Did your biocube have a lid? If so, that'll make a huge difference in the amount of water you need to replace due to evaporation.
The biocube does have its lid still. With that thing I've never had to add more than a cup or two in between water changes.
 
If you're patient, you can find a tunze 3155 for $115-125. I like the dual sensor ones that can turn off in case it fails "on" (eg dumping a ton of rodi into your system).

You can find/build super cheap gravity fed ones, too.
 

max_nano

Supporting Member
You can use any of the following:
https://www.bulkreefsupply.com/auto-top-off.html

I actually sold my old Tunze ATO for really cheap, too bad you missed that.

You can get a ATO and a 3-5 gal carboy to hold RO water to top off as your tank evap's. Greatly helps.
I’d get something larger than 3-5 gal for a 40gal tank. Unless you want to be refilling it more than once a week. Lots of factors go into evaporation rate but it’s definitely nice to go big for the ATO res so you can rely on it if you want to ever go away from the house for a few days
 

ofzakaria

Supporting Member
So with my biocube I guess I was lucky. I had no idea how big a deal evaporation was. Now that the 40 is starting to cycle I'm noticing the water level in the sump dropping daily and salinity going up and up. I do have an ro/di system to replenish the water but what I really want/need is an A.T.O. system. Can anyone recommend and decent cheapish ato? Anyone have one for sale they want to get rid of?
Get a 2 floats ATO.
If you have a controller you just need to add the 2 floats this will be the cheapest If you do not have a conteoller, there are some very good stand alone ATO out there.

If you can plumb the RODI to the tank you can potentially simply add a float valve to the tank and connect it directly to the RODI..
 

svreef

BOD
Staff member
I used this one which is $120

 

ofzakaria

Supporting Member
I used this one which is $120

I got similar ATO in the frag tank, the smart ATO micro which is also optic based. I do not like it and I conclided its not reliable.
Switched to float based similar to my display tank which I have been using for almost 10 years.
 

Patio

Supporting Member
I have never had an issue with the Smart ATO micro. I have never had an issue with any ATO. Currenty but not always- I have room in my system if the ATO stays on and only enough water in the reservoir (3.2 ish gallons) to change the specific gravity to 32.5 ppt from 35 ppt if the ato is stuck in the on position.
 

max_nano

Supporting Member
I got similar ATO in the frag tank, the smart ATO micro which is also optic based. I do not like it and I conclided its not reliable.
Switched to float based similar to my display tank which I have been using for almost 10 years.
What issue did you have? I have had no issues with mine
 

reefjedi

Supporting Member
If you decide to go with the optics based ones, be sure to get one with good optics. I heard there are issues with some of the lower quality ones that trigger false alarms and wake up you several times in the middle of the night... like the icecap ATO. Whatever you do, don't get the icecap ATO. Tons of issues with it on the support forums.
 
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