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Sun Tea Jar Auto Top-Off


GreenUku

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Sun Tea Jar Auto Top-off

 

I promised at the beginning of the summer that I would post a how-to for a cheap gravity-fed auto top-off. Well the summer was busier than expected, and if your lazy like me, that's a death knell to side projects (even easy ones like this). Anyway, here's my how-to and discussion for a sun tea jar auto top-off:

 

What, How, and Why:

This auto top-off is gravity fed and controlled by pressure (no pumps or float switches). I don't know if there is a good, catchy name for it, but it doesn't seem to be a very popular type of auto top-off, even though it is arguably better than the float switch type for smallish tanks. That's why I thought I'd post plans for a cheap, easy version.

 

 

The way this top-off works is pretty simple. The air inlet tube is placed at the level of the desired water line. The drip tube puts fresh water back into the tank. When the water level reaches the air inlet tube, the water prevents air from entering the container and the dripping stops. In practice, water is actually sucked up the air inlet tube until it rises to a level where the pressures in the container offset each other. When enough tank water evaporates, the water level drops below the air inlet tube, letting air into the container, and top-off starts again.

 

I've been using a similar top-off on my main system for about a year and have had very few problems. Here are what I see as advantages (over other auto top-offs):

  • Cheap (this one cost me about $10, though fancier versions can use some expensive parts)
  • Very low maintenance
  • Relatively failsafe (no moving parts)
  • Works (maintains your water level automatically)

 

Specifically, this version that I built was very cheap with (relatively) easy to find parts. (More on this later.)

 

Parts:

  • Glass sun tea jar with plastic lid ($4 at the grocery store, a seasonal item)
  • 1/4 inch (outer diameter) tubing (standard airline tubing, I got 20 feet of vinyl tubing for less than $2 at Home Depot)
  • 3/8 inch (outer diameter) tubing (about $4 for 25 feet of polyethylene tubing at Home Depot)
  • Number 4 rubber stopper ($1 at a chemistry supply store)
  • Silicone aquarium sealant (a small tube is a few bucks [~ $3])

 

There are a number of reasons I went with the glass sun tea jar. For this top-off to work the container needs to be very rigid. Besides being cheap, the sun tea jar is rigid, pre-drilled at the bottom, and even comes with it's own bulkhead (sortof). Unfortunately, sun tea jars only seem to be for sale at the beginning of summer every place I've been. I was going to use one a year ago, but I waited too long and they were no longer for sale.

 

 

DIY

  • Saw off the end of spigot so only a hole is exposed.
  • Insert a piece of 3/8 inch tubing (a couple inches long) into the "bulkhead". I had to shave my tubing down slightly on the end, but then it went in, providing a tight fit. This part will act as an "adapter".
  • Place the end of the 1/4 inch tubing into the end of the piece of 3/8 inch tubing. Mine fit snuggly. If it doesn't, you can silicone it.
  • Make a hole in the top of the lid for the 3/8 inch tubing. I actually hand turned a small drill bit and then used scissors to enlarge the hole. Not very fancy, but it worked.
  • Insert the 3/8 inch tubing into the hole.
  • Important: the whole container needs to be absolutely air-tight.
    * Put silicone sealant around the 3/8 inch tubing on both sides of the lid.
    * Put sealant on the hinges of the handle (on the inside of the lid).
    * Put sealant on the inside rim of the lid and carefully screw onto jar.
  • After the sealant cures (at least a day), mount the 3/8 inch tube so that its tip is at the level where water should be. Mounting can be tricky. I suggest doing something with plastic cable ties.
  • Place the 1/4 inch tube so that it can drip into the tank. A knot in the tubing can restrict the flow to what ever rate you want.
  • Fill sun tea jar with fresh water, put stopper firmly in fill hole in lid, and let the testing begin.

 

I would suggest letting the top-off run on your "test tank" for at least a week. Any air leaks or blockages in the setup can result in a gradual change in the water level, either too low or too high.

 

Considerations

As I said before, sun tea jars are generally a seasonal item, so it might not be easy to find one if it isn't summer. On my main tank I built a very similar top-off with an acrylic jar/canister that was sold as packaging for pasta. In any event, the container you use needs to be RIGID!

 

The reason for the 3/8 inch tubing as the air inlet, is that water will just stay in tube of smaller diameter due to surface tension, not letting the drip restart.

 

I have noticed that when the water level drops and air first enters the inlet tube, some tank water is sucked into the container. Over time, this leads to a lot of algae bits and such ending up in the container. If this happens, you should occasionally flush the container with fresh water, which may entail removing the drip tubing.

 

A more robust design would probably involve something other than a rubber stopper (my other top-off has a ball-valve), and easily deatchable tubes, for cleaning or replacement. Also you might consider using an IV dripper instead of just airline tubing for better control of the drip rate.

 

Note that in my pictures I was using a 1/4 inch tube as the air inlet, but I discovered that the tubing was in fact too narrow.

 

Well, I hope someone gets something out of this. Let me know if you have any questions. Feel free to copy these directions and improve upon them. I'm freeing it to the public domain.

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Glass sun tea jar:

 

Cut spigot and drip tube assembly (sounds fancy):

 

Top of the sun tea jar lid with silicone sealant around the air inlet tube:

 

Bottom of the sun tea jar lid with silicone sealant. Notice the sealant around the holes where the handle on the lid is attached:

 

Sun tea jar lid with rubber stopper (#4) and air inlet tube:

 

 

Testing:

 

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neanderthalman

Alright, I built the same autotopoff a while ago, using an old liquor bottle, but I can't seem to get it to work right. Once the air inlet tube gets water in it, the topoff won't start again, regardless of whether the end of the inlet tube is submerged or not.

 

You mentioned that you found that the 1/4 inch inlet tubing was too small - is this why? I had thought that a larger hose would prevent capillary action from holding the water in the tubing, but I havent had a chance to try it.

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neanderthalman:

Yes, the problem is that the air inlet tube is too narrow. You could use a very wide tube as long as it is airtight. This is just pressure, like a vacuum cleaner, which is different than capillary action, which does require a vary narrow tube.

 

Hope that helps.

 

GrizzleBee:

Thanks. I actually made one like this a while ago and originally got the (not so original) idea while looking at this:

 

http://www.cs.cmu.edu/~cap/raid/topoff/sip...phon/index.html

 

JAYJT78: thanks.

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Yes the concept is a good one but not everyone can mount their FW above their sump or display tank. As mentioned, the air suction tube needs to be fairly wide (like 1/2" or more) but the water discharge can be a small diameter airline tubing.

 

GreenUku wasn't sure it had a name, and I'm not sure either, but I propose VDTO for Vacuum-Driven TopOff, kinda like we named the pressurised airpump topoff system ADTO, Air-Driven TopOff. And of course there's also DATO, Dakar's Auto-TopOff system: http://www.reefcentral.com/forums/showthre...threadid=654436

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How about Vacuum Regulated Top Off (VRTO). Pronounced ver-to.

 

Or Pressure Regulated Top Off (PRTO, per-to).

 

I didn't realize we'd get to come up with the catchy name. Maybe somehow we could fit in laser or robot or even quantum to make it catchier... Sweet. :D

 

...or even NANO!

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  • 5 weeks later...

Agree that there are not many of us who can mount a sun tea jar over our tank although I think the work, design and concept are excellent. If you don't mind topping off as a 'weekly chore', my design was similar. Just drilled a suction canister from a hospital at the bottom, glued in tubing with silicone. I fill it with 1 liter of pure water every other day, set it on top of the tank at night and it drips in, finished in a few hours. SH

 

nano18.jpg

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  • 6 months later...
Do you keep a mini heater in your Jar?

I built a shelf above my 12 nano and just fed it via a drip and a large gatorade bottle. Works great and if it were to fail it would only lower the salinity to around 1.021 PPM which should keep every thing in the tank alive

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  • 1 year later...
  • 3 weeks later...
mrabolli said:
keep it alive! bump

 

Doing my best. I haven't been hanging out on NR as much lately because I've been working on a 65 gallon system. I know, I know... ;)

 

Since a few people have asked me about this, here's a picture of the container I've been using for the last 3 years for this kind of top off (I never set up the little tank I was going to use the sun tea jar topoff with).

 

The container is an acyrlic canister (about 1 gallon) that originally held some sort of pasta. That's probably the cheapest way to buy one if you can find it. I think it was purchased at Sam's Club.

 

 

 

Unlike the sun tea jar, I added a bulkhead to the top with a ball valve attached to add water. The drip line and air inlet tube are going through one-holed rubber stoppers, though if I rebuilt it today I might try using some rubber grommets (like little uniseals).

 

I've had almost no problems with this setup, except for the drip line (an IV line) occasionally getting clogged or staying pinched by the thumb roller that controls the drip rate. But I consider those very minor problems that are easy to fix.

 

Good luck and post up any pictures of your own versions here.

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  • 1 month later...
Sun Tea Jar Auto Top-off

 

A more robust design would probably involve something other than a rubber stopper (my other top-off has a ball-valve), and easily detachable tubes, for cleaning or replacement. Also you might consider using an IV dripper instead of just airline tubing for better control of the drip rate.

Note that in my pictures I was using a 1/4 inch tube as the air inlet, but I discovered that the tubing was in fact too narrow.

 

Is it possible to show us your other design the one with detachable tubes.

 

and sorry for this question how do you refill the gar when you open the cover will the air go in the gar until you fill.

 

please i like this very much specially for my 2.5g but i like to be more per sized about it before i make it.

 

thank you

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  • 2 weeks later...
Is it possible to show us your other design the one with detachable tubes.

 

and sorry for this question how do you refill the gar when you open the cover will the air go in the gar until you fill.

 

please i like this very much specially for my 2.5g but i like to be more per sized about it before i make it.

 

thank you

 

 

i couldnt get this design to work. I used a very ridgid hard plastic beverage container from K-mart. I used a large diameter (1/2" I think) tube for the pressure line going in the top. The container would develop a negative pressure indeed as the sides were bowed in slightly but the water just continued coming out of the fill line (1/4" tube) no matter what I did. It was air tight. Weird.

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Is it possible to show us your other design the one with detachable tubes.

 

and sorry for this question how do you refill the gar when you open the cover will the air go in the gar until you fill.

 

please i like this very much specially for my 2.5g but i like to be more per sized about it before i make it.

 

thank you

 

The detachable tubes are on the one pictured above (the acrylic canister with the ball valve). Basically I just put some stiff tubing through single-holed rubber stoppers. Then you can just put the flexible vinyl tubing either over or inside the stiff tubing.

 

You refill the jar by removing either your rubber stopper (on the sun tea jar version) or opening the ball valve (on the other version). If there is pressure built up, this will release it, but afterwards it will only drip enough water to build the pressure back up. My system only adds about 20ml (3/4 oz) to re-establish the vacuum hold, if the water level is already correct. That amount depends on the volume of your air inlet tube.

 

I don't have the link on hand, but someone on NR has built a very small version of this using a nalgene-type water bottle for their small nano. If anyone has the link, please post it.

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i couldnt get this design to work. I used a very ridgid hard plastic beverage container from K-mart. I used a large diameter (1/2" I think) tube for the pressure line going in the top. The container would develop a negative pressure indeed as the sides were bowed in slightly but the water just continued coming out of the fill line (1/4" tube) no matter what I did. It was air tight. Weird.

 

Usually problems are caused by either the container not being rigid enough or the seal not being completely airtight. Often, if the container deforms due to the pressure, it can compromise the seal. By rigid, I mean you should barely be able to push the container in by squeezing it with your hand, if at all. I would try re-sealing, or if you aren't sealing with silicone (or something), try sealing everything.

 

When you tested the topoff, was water lifted up into the air inlet tube? The water will not stop dripping from the outlet until it reaches a certain level (above tank water level) in the inlet tube. That's the level that balances out the pressure in the reservoir.

 

Good luck.

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  • 1 month later...

I'm trying this now with a Wal-Mart acrylic jar thing... the entire top is one of those sealed-tops via a metal latch and rubber/silicone o-ring. I drilled a hole thru the lid and near the bottom and snuggly fit some tubing in and have sealed it... waiting on the sealing to cure and then I'm gonna see how it goes.

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  • 8 months later...

I'm having problems with this. Iv'e just gone through and re-siliconed everything, even though nothing leaks. I'm using 1/2 inch piping and tubing for the air intake and 1/4 inch tubing for the drip. water will flow up the air intake for a little and then it won't go anywhere but water keeps coming out of the drip...

 

any ideas?

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fairly sure, I filled the container with water and turned it upside down, no drippage. I just finished applying a generous second coat of silicone, I'm going to let it dry overnight and see how it goes in the morning.

 

edit** - aha!!! I found a minute - ridiculously small pinhole. I had to watch for minutes to see one drop of water come through, but I found it.

 

 

VICTORY!!!!

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this is a major flaw of using air tight jar. The other is, even if the float switch turns off, water will continue to flow until pressure equalizes.

 

It is better to just use a small pump that cost only $7-$10 or so. The worry about running dry is overrated. If you run dry, you have more things to worry about than a $10 pump.

 

You can make one using a pump wired in series with a float swtich and a short piece of vinyl tube going from pump to your tank and will cost under $20 (if you can find a float switch that is cheap, I found one for $7.49 a while back). Or you can buy one ready made plus a pump for around $28+$10. Since you already have a float switch, all you need to add now is a small pump.

 

I got this on sale for $4.99 at a local store.

http://www.harborfreight.com/cpi/ctaf/disp...temnumber=45303

 

or if you worry about running dry, then get this for $9.99

http://www.bizrate.com/reptilesupplies/oid23267113.html

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