Auto Top Off System

[Ichthys]

I want to put in an ATO and have a few questions. I am leaning towards a float valve that gravity feeds from a reservoir above the sump as opposed to a float switch with pump. I will have a 5-10 gallon Sterilite type container with a bulkhead and hose leading down to a float switch in the sump below. The water from the ATO will enter the sump in the return pump area, that is the section where my main return goes back to the DT. I have heaters in the sump in that section.
Here is my question. Is it necessary to heat the ATO reservoir? I am thinking that if the float switch activates several times daily and only allows small amounts of fresh RODI water into my sump at one time, then it doesn’t matter what temp because the much greater quantity of water already in the sump will compensate for temp difference.

Some math…. the return portion of my sump is 15x12x7 which equals 5.45 Gallons.
If the level drops 1 inch before the float valve actuates then the volume of water entering the return area once the valve opens would be .779 gallons. So here is the question.

Would ¾ of a gallon of cold (say 65 degree) water entering and mixing with the 4.75 gallons of 77 -78 degree water in the sump, cause enough of a temp drop to negatively impact my livestock in the DT. Keep in mind a few variables, 1) turn over through sump is about 400GPH so the 5.45 gallons would take less than 1 minute to enter the DT. Cold water would probably sink meaning the return pump from sump to DT may shoot all ¾ of a gallon of cold water straight into the DT before it really mixes with warmer water in sump. Does ¾ gallon cold water entering a 55 gallon tank at 7GPM make much difference in overall temp? Am I overthinking this?

What are experiences with float valves? Is a 1 inch drop before activation normal, or does it activate at smaller increments. Smaller would be great, larger would be bad as we would be increasing the cold water entering the system. Say if it was 2 inches, we now have 1.5 gallons of cold water entering the sump…. I suppose I could figure out some mathematic way to determine temperature drop of a volume of liquid when a lower temp enters. Those guys that track the icebergs around the north Atlantic could probably do this in their sleep…

Ichthys

 

[DonW]

Float valves are problematic. All you need is two float switches, a 12pump and power supply. No relays or other 110v devices.

Don

 

[jill]

I still have a float valve reservoir system on my 300 g system. I don't think temperature or pH is too much of a problem unless the valve fails.

I had a terrible experience 6 months ago when my float valve malfunctioned and was hooked into my RO distiller. About 20 gallons ran into my pump and I caught it just before it overflowed. Thank god I was home. But as it was that much water affected the salinity, pH and temperature in my tank and one of my Heniochus got popeye. It could have been much worse.

Now I keep less than 10 gallons in a separate gravity fed system and make sure the pH is close. I also check the float valve regularly to make sure its working properly. I'm not sure what would be an appropriate amount for a 55 g.

Any type of system can fail. I have an Osmocontroller ATO on my nano and it works great but you still need to clean the glass float controller periodically - it gets coraline an crud on it that can freeze it up.

 

[nwinverts]

I don't worry about heating my topoff water, It's being introduced in such small amounts that it doesn't effect my tank temp. If your using swithes as DonW mentions, you won't be adding .779 gallons at a time. As DonW says use two switches,one above the other.

Here is a vid on a bacic inexpensive ato. I don't agree with everything the kid has to say. eg. He calls what he is using a float valve, he is in fact using a float switch, but it will give you a good starting point. Obviously your working with electricty and water so use the usual precautions. http://reeflove.com/diy-auto-top-system

 

[TheKraken]

I am still new to reefs, YMMV. My sump came with a drilled port and a float valve so I hooked it back up. I feed with a 5 gal collapsible container (REI) on the canopy. The idea is that worst case = 5 gal.

Now, being clever I also saturate with Kalk water. I have noticed the formation of a white block forming on the float but the water level is constant so far...

With a float valve the float presses on a valve. When the pressure of the float is equal to the float the flow stops. Most the time however the valve is just weaping with a slow and continuous drip. This type of valve does NOT dump water in as described in the OP.

For a "powered" ATO just size the pump to the rate of evaporation so that you have the right duty cycle (ie control the fill time from the low-on to the high-off).

 

[Ichthys]

ATO

One thing i cant figure out. If you use a powerhead and float switch, and the fresh RODI reservoir (say a 5 gallon container) is ABOVE the sump, then even with power to the powerhead interupted it is going to continue to siphon all the water out of your ATO reservoir into your sump... how do you get around this other than putting the ATO BELOW the Sump.

 

[Holygral]

I use a Reef Fanatic with 2 floats. The first float is in the sump and set to top off when the water is low, the second is in the display tank and set for high, so if something happens to the float in the sump, the float in the display will shut the controller off. If the display float is activated the top off willnnot com on.

 

[mcoomer]

Best money I ever spent...Tunze Osmolator. Look around and you can find them for sale on the various forums in the $100-125 range. I got mine for $115 with all the tubing, mounts, kalk dosing container, and an extra pump. I mounted it all inside a 5 gallon bucket and use it on the 20G that I have setup next to my bench in the garage. Fill the bucket once a week and put fresh kalk in the container every two weeks and I'm good to go.

Mike

 

[burning2nd]

www.autotopoff.com

 

[DonW]

I am still new to reefs, YMMV. My sump came with a drilled port and a float valve so I hooked it back up. I feed with a 5 gal collapsible container (REI) on the canopy. The idea is that worst case = 5 gal.

Now, being clever I also saturate with Kalk water. I have noticed the formation of a white block forming on the float but the water level is constant so far...

With a float valve the float presses on a valve. When the pressure of the float is equal to the float the flow stops. Most the time however the valve is just weaping with a slow and continuous drip. This type of valve does NOT dump water in as described in the OP.

For a "powered" ATO just size the pump to the rate of evaporation so that you have the right duty cycle (ie control the fill time from the low-on to the high-off).

This set up is a disaster waiting to happen. Kalk and float valves dont mix. One day the whole container is going to dump into your sump and destroy the reef.

Timing a pump is not realistic for specific level control unless your using a low volume pump such as an aqua lifter. The timer need to be an interval timer capable of precise timing in 1 second intervals. It will work but the level will alway be either high or low unless you have a precision timer.

Don

 

[DonW]

Here is a vid on a bacic inexpensive ato. I don't agree with everything the kid has to say. eg. He calls what he is using a float valve, he is in fact using a float switch, but it will give you a good starting point. Obviously your working with electricty and water so use the usual precautions. http://reeflove.com/diy-auto-top-system

This kids video has been around for a long time and should be pulled from the web. The set up is dangerous and should not be used. ALL 110V should be switched with a low voltage DC relay.

The easiest way to make a safe ATO without a relay is to follow the kids video buts substitute the extension cord for a 12vdc power adapter (wall wart) and use a tunze osmolator replacement pump. Anyone can safely build an all low volt dc ato.

Don

 

[DonW]

One thing i cant figure out. If you use a powerhead and float switch, and the fresh RODI reservoir (say a 5 gallon container) is ABOVE the sump, then even with power to the powerhead interupted it is going to continue to siphon all the water out of your ATO reservoir into your sump... how do you get around this other than putting the ATO BELOW the Sump.

Use a small pump like an aqualifter and a vacuum break.

Don

 

[Herefishyfishy]

Use a small pump like an aqualifter and a vacuum break.

Don

Agree with everything Don has said.

Easiest vacuum break is a hose splitter (doubler) with an adjustment on the extra line placed within the reservoir container above the waterline. Can be a valve, pinch clamp or even a loose knot tied. When the pump runs, a little drains back into the reservoir through the vacuum break line. When the pump stops, air is drawn into the extra line breaking the vacuum

 

[Ichthys]

Good Idea

Agree with everything Don has said.

Easiest vacuum break is a hose splitter (doubler) with an adjustment on the extra line placed within the reservoir container above the waterline. Can be a valve, pinch clamp or even a loose knot tied. When the pump runs, a little drains back into the reservoir through the vacuum break line. When the pump stops, air is drawn into the extra line breaking the vacuum

Herefishyfishy
What a good idea! I cant believe i didnt think of that but I guess sometimes the easiest answer is the best one.

On a separate note, Don you said Float Valves are problematic, how so? What are the downsides to them in particular?
Ichy

 

[DonW]

Herefishyfishy
What a good idea! I cant believe i didnt think of that but I guess sometimes the easiest answer is the best one.

On a separate note, Don you said Float Valves are problematic, how so? What are the downsides to them in particular?
Ichy

They stick open so if you connect it to an rodi you could flood your house. If its just a container then you dilute your tank by however much the tank holds. If its kalk then you've probably destroyed your tank. A float valve is nothing more than a float that raises up and covers a hole. Salt creep, snails and kalk are failure causes. They are NOT designed to be used for anything except pure water applications. Kalk you can count on the fact that the precip WILL ruin the valve.
Two float switches are best. One is the work horse the other just hangs out unused out of the water as a back-up. One WILL faill eventually and the other will take over without damage to the tank.

Don