auto-top off ideas

[daveb]

The float switches that I posted the picture of keep the tank within 1/16th of an inch level accurately. They don't even have a 1/2 inch throw. They turn the air pump on and off many times a day, only adding a few ounces of water each time. The container I use is made of that blue tinted plastic for drinking water, and you can see the lines left after each time the air pump turns on and off. The water level in the bottle drops less than a quarter inch each time the pump comes on. As a matter of fact, while writing this, I went and added water to the bottle to fill up to one of the lines left after the pump last turned on, and it took only 6 ounces of water to fill it back up to the next line. So the way my system is set up, everytime the pump turns on, it puts 6 ounces of water into the sump... not very much considering that I have a 50 gallon sump. The way my system is set up, even if the first float switch stuck closed, the second switch would shut down the pump before it put less than a half a gallon of water into the sump...nothing to worry about at all.
I believe that this is probably almost as accurate if not as accurate, as the Tunze. Keep in mind that these are not the float valves, but electric switches, which do not need near the throw that a valve needs. The Tunze system is no doubt a very good and accurate top off system, but, I believe that for a lot less money you can do the same thing with these electric float switches and the air pump. If money is no object, the Tunze system is a fine choice no doubt. But for those who are on a tighter budget, this system works just as well...
Dave

 

[pyro]

Yep, budget is a problem. Don't mind spending the money on somethign like a good skimmer, but otherwise I'm pretty stingent. Could I possibly use 3 of the 6$ ones? One for the normal operation, one submerged and one out of water for a safety in each direction?
I'm also assuming the electronic sensors Tunze uses are very similar to the photogate things we use in physics. I bet you could find the sensor for not too much and set one up yourself... just an idea.
I'll probably use a 3-5g new gas can from walmart or somewhere. Space under the stand is sortof limited, and going to install a small shelf to store small supplies on.
Thanks for all the help!

 

[salty cheese]

Does the Tunze hook up to your RO unit or does it draw water from a reservoir? Some pics of it all set up and working would be great.

 

[msd2]

Originally posted by Salty Cheese
Does the Tunze hook up to your RO unit or does it draw water from a reservoir? Some pics of it all set up and working would be great.
I use mine setup into a reservoir. I use the osomater (sp?) but they have another model if I recall correctly that is designed to interface with the DI unit. The model I have is a super simple and clean install into the sump. I have never used only float switches, but had used float valves which my experience was less than pleasureable repeated times. After 3 floods I had given up on an auto topoff system. And yes I did clean it regularly. And to be honest I travel too much and don't need to be worrying about the topoff system failing or the sump running dry. I will attach a few pics.
Main sensors, the light sensor and the back up float switch:

 

[msd2]

the control box, which will turn off the pump automatically if for some reason the photo and the float switch fail after 10 min.

 

[msd2]

finally the pump. Its a simple, but effective system. And if a flood is something you can't risk IMHO this is money well spent. I would say if you can design a system similar setup with your lab access id say go for it and save a few bucks if your confident in your skills. I for one wasnt after my experiences with the float valves and to be honest I didn't want to try and figure out how to make the system as redundent and as well designed as the tunze. Just like their powerheads, its pricey but you see where your money went.
Not the greatest pic of the pump, but its small and will fit in most 5 gallon container openings. The final piece, which I wont take a pic of is the hardware that holds the return hose from the pump to the sump. Its an inclusive package with the controller, 2 sensors, pump, and rails for mounting the hardware.

 

[pyro]

Sorry, I can't get a good look at the light sensor from the picture. Is the sensor only one part? Or is there another part beneith the water? I'll ask my physics teacher (used to work for nasa and now sarcastically jokes high school students for a living) and my systems engineering teacher about ideas, one of them will have an idea I bet.
Thanks!

 

[msd2]

Originally posted by Pyro
Sorry, I can't get a good look at the light sensor from the picture. Is the sensor only one part? Or is there another part beneith the water? I'll ask my physics teacher (used to work for nasa and now sarcastically jokes high school students for a living) and my systems engineering teacher about ideas, one of them will have an idea I bet.
Thanks!
yup just one part, shaped like a bullet. If you look closely at it got a clear strip down the center that goes up the side partially. Id take a closeup pic but ur not supposed to expose it to bright light.

 

[daveb]

I would not trust float valves at all myself. Float valves are valves, so you have two parts to fail, the valve and the float...and I have read many horror stories about float valves failing. and since the valve is all that controls water flow, if it fails, there is no backup to stop overflowing..
With float switches, the switch controls the airpump. The airpump is what moves the water. I have seen similar setups, in which the float switch controls a water pump or powerhead, and I would not trust that setup either, because the pump or powerhead moves too much water too fast, so in the event of a switch failure, the amount of water able to be moved by the pump could very well be too much in a very short period of time. The airpump, moves very small amounts of water, very slowly in comparison to water pumps or powerheads.
And lastly, my sump is able to hold all of the water in my top off water reservior if the unlikely event of two float switches failing at one time should happen...
Dave

 

[pyro]

yep, they will be controlling an air pump. My tank system will be able to hold all the water in the resovoir aswell. That is why I am equally as worried about it sticking the other direction. If it fails in that direction, and I don't notice it within 24 hours, my pump will be sucking air.
Thanks

 

[salty cheese]

A belated thanks to msd2 for the pics.

 

[manjisann]

Sorry to hijack the thread, but DaveB, I am thinking of getting a nanocube and was wondering if you think the switches you recommended could be used in the back to do the autp top off system you recommended?

 

[msd2]

Originally posted by Salty Cheese
A belated thanks to msd2 for the pics.
certainly. Honestly I can say this has been one of my better buys. Solved a lot of concerns about dry sump, changing salinity, and I dont ever give it a second thought :joy:

 

[daveb]

Absolutely it would work very well for a nano tank... your evaporation will not be great, so you won't need a huge top off water container. You probably would not have to worry about top off water for weeks at a time with a 2 1/2 gallon container. The only thing is that those float switches need to be in some sort of mounting that protects them from Snails and water movement... here is a picture of one I did. It doesn't look too bad and would be hanging very close to the top of the tank..
Dave

 

[daveb]

I will try again...

 

[manjisann]

:happy: Thank you so much, that eliminates 90% of the pain of haveing a nano tank!!:happy:

 

[pyro]

sorry for digging this old thread up, but i finally got my auto top off sturcture complete. I was deciding whether to use a float switch or just a timer.
I originally thought about the timer, but I soon voted that idea out. I used a 5g glue clearish plastic water container used for drinking water that had a threaded top. The time it takes to pump water at the bottom is at least 5 times what it takes to pump when the tub is filled due to the height and volume.
So, it seems the float switch is the winner. On the ones Dave posted, what happens if the water gets above the float valve? Do you silicone around all the open parts to make sure they are water tight? That is a lot of currrent running through a tank... Also, do you have to order them via phone or are their commercial websites that sell them (don't list them, just let me know if they exist).
Thanks!

 

[daveb]

It is a website you can buy those switches from. Water can be all around the switch. If the switch is floating , it shuts off the circuit, if it is not, it opens the circuit.... Sometimes, I intentionally overfill my sump, so that it has a day or so before the auto top off has to start working.... that gives me an extra day or so that I can be gone without having someone else check on the top off water...
When you get one, you will see how it works..
Dave

 

[pyro]

Any problem with using two safetys? Im more worried about it not turning on than if it stays on too long.
I'd do one above and one below.
sorry about the poor grammar - right hand has cast on

 

[msd2]

Originally posted by Pyro
Any problem with using two safetys? Im more worried about it not turning on than if it stays on too long.
I'd do one above and one below.
sorry about the poor grammar - right hand has cast on
I would think you would want at least one backup for the main float. I would assume you guys are wiring the upper one when moved upward it breaks the circuit and shuts the pump off correct? vice versa for the lower one, meaning when the float is in the lowest position it closes the circuit and runs a pump until it moves up and again breaks the circuit? imho you would be crazy not to build in some margin of safety. Thats the same config the tunze uses the photosensor and then above it a float shut off that shuts down the pump.