DIY: Gravity Fed Auto Top Off

[SuperDragon]

Ok, summer's coming again and so will the heat and my aux fan.
I used this on my 12g SPS tank.
Someone was asking about my fancy auto-top off unit.
It cost me like ~$500~ j/k

This can work for a sump also for a larger tank, if you play your cards right (i.e. 5gal bottle).

I don't like noise, IV drips, electric ATO ($$$), etc.

Pro's
-gravity fed/no power
-easy to maintain
-adding water only every 10-14 days
-no float switches
-no pumps
-cost almost nothing, from stuff laying around
Neg
-becareful prior to water changes

TIME: 30 min
MATERIALS: 1/2" acrylic tubing (plastics store) or pvc is fine
1/2" pvc valve (optional)
Weld on #3 or #4 or pvc cement

I had to drink the whole bottle of grape juice, but any flavor will do.
Clear bottles are easier to see.

simple setup



ridgid airline tubing Dosn't work, must be larger, I used 1/2" for less noise
and faster delivery, proper air/water exchange

-cut hole in the bottle
-heat bent 1/2 acrylic tubing
-inserted ridgid acrylic tubing 1" into bottle
(farther into bottle, takes more time for air/water exchange. If you put the tubing right at the bottle then after filling the bottle it will run out fast)
-glued on (weld on #4 or #3, I don't rec silicone too weak)
-secure tubing (wire, airline, whatever you have handy)
-cut the tubing after placement to water level you want
-You can add a valve at the drain for easy maintenance
-water just must be above water, I made a stand

=Filling=
-lock the lid/cap air tight (could even glue it on)
-invert bottle and fill from the drain
-use your finger to plug when inverting and place into tank
-test it by removing water
-check for leaks

I would start with plain water for 24 hours, if good then one could move to Kalkwasser (like I did)

=Caution=
If you don't add a valve.
When doing water changes make sure the drain is plugged or you'll get hyposalinity all over the place
If you add a valve then, turn off, do water change, turn on

There are many variations of this:
Sun Tea Jar
http://www.nano-reef.com/forums/inde...554&hl=sun+tea

Just looking at the sun tea jar mod, I can see disasters happening
K.I.S.S.

Happy Reefing

[sandiegoryu]

Awesome guide!

But what's wrong with the tea jar method?

[SuperDragon]

If your airline at the top of the tea jar leaks
If your airline seal is not 100% air tight anywhere
If your trying to do a water change you have to plug up the airline
Algae can grow or get sucked up the airline and plug up the airline
Difficult to fill up the Tea Jar :/
Using small airline delivers burts of bubbles that are noisy :\
(my unit gives the watercooler gurgle)

Hyposalinity will not kill your fish or livestock temporarily.... Hyperalkalinity from Kalkwasser will kill everything.
I alway keep that in mind when testing the unit for the first 24-48 hours. (start with water)

I'm not saying that it dosn't work, I built one, tested it and then threw it out before putting it on my tank, I just can't see myself using it... too many excess parts for no reason.

One tube for air and water... less risky I think.
I might add the valve someday, but everything is working fine.
If it's not broken...

[tom619]

i understand the sun tea jar's concept because there are 2 tubes: 3/8" for air and 1/4" for water, but i don't quite understand how yours work...? is the air tube inside the water tube?

*brain fart*

[Redeye]

when water level drops below his tube, it will suck abit of air, causing water to come out of container and into tank, hence the Water cooler gurgle

[SuperDragon]

Redeye is correct.

The single tube is for air and water exchange.
Just like a 5 gallon watercooler/dispenser

Same principle when you pour liquids out of any container that has a small neck like a 2 liter bottle.

In fact, I could have inverted a 2 liter bottle on the back of my tank if it had a longer neck and a way of keeping it stable upside down.

[tom619]

ohhhhh

gotcha. thanks

[sandiegan]

There's a problem with that Long.

Since the water in the bottle is touching the water in the tank, it'll mix. Salt will diffuse into the water bottle. I know my terminology isn't quite correct, but osmosis and equilibrium states, right?

[Sam Maghsoodloo]

Nice job! What you built should be your proof of concept, not your actual device. Build it again but more legitimately this time.
Use 6" abs pipe, with 2 end pieces as your container. And then tap it on the side and put the tubing on there. Either that or something nicer looking than a grape juice bottle
When you heat bend your tubing, fill it with warm sand first, and tape the ends, that way it doesn't kink when you bend it. You could also seal it and blow into it to keep it round when it bends, like a glass blower. I would just buy a U-tube and cut it in half, they're cheap and you can buy them at the lfs. (actually, i wouldn't use large pipe at all, you should just use more airline. The flow is going to be really minimal)
Also, you can feed your airline through your intake (if you use a big one), up into the container, that way it looks slicker.


I love when people build stuff, that's what makes us human. Never stop redesigning

[Sam Maghsoodloo]

There's a problem with that Long.

Since the water in the bottle is touching the water in the tank, it'll mix. Salt will diffuse into the water bottle. I know my terminology isn't quite correct, but osmosis and equilibrium states, right?

Yes, this is another problem, although not a huge one. You could fix it by not using a large tube. Also, fish can swim up into your reservoir! Or perhaps snails.

[sandiegan]

Not trying to pull it apart (I like the idea) but how is it not a huge problem? It's effectively lowering the salinity of everything by the 1g, and the salt will diffuse fairly quickly so it's not that slow...

[SuperDragon]

There's a problem with that Long.

Since the water in the bottle is touching the water in the tank, it'll mix. Salt will diffuse into the water bottle. I know my terminology isn't quite correct, but osmosis and equilibrium states, right?

Thought about your question and check my salinity every few days to keep in check and it is.
Saltwater is heavier than freshwater, the diffusion gradient is still going up the bottle; however, because of gravity, the salt molecules would have to overcome gravity to diffuse into the bottle...

Also, the tube is 1" inch into the bottle so that air/water exchange is slower (for my sake not to spill water loading the bottle, not diffusion)... if diffusion is occuring it is minimal. I'm sorry I wasn't clear on that.

Thanks for your input (had me doubting there Mitch)
Almost PIF you another coral.

[SuperDragon]

Yes, this is another problem, although not a huge one. You could fix it by not using a large tube. Also, fish can swim up into your reservoir! Or perhaps snails.

It's in the back chamber of the 12g nothing goes back there, also a splash guard to keep fish out. Smaller tube, less flow, more noises, difficult to get air/water exchange. Unless you do a Sun Tea Jar style.

If you a larger use one for a sump there shouldn't be fish down there.

[SuperDragon]

Nice job! What you built should be your proof of concept, not your actual device. Build it again but more legitimately this time.
Use 6" abs pipe, with 2 end pieces as your container. And then tap it on the side and put the tubing on there. Either that or something nicer looking than a grape juice bottle
When you heat bend your tubing, fill it with warm sand first, and tape the ends, that way it doesn't kink when you bend it. You could also seal it and blow into it to keep it round when it bends, like a glass blower. I would just buy a U-tube and cut it in half, they're cheap and you can buy them at the lfs. (actually, i wouldn't use large pipe at all, you should just use more airline. The flow is going to be really minimal)
Also, you can feed your airline through your intake (if you use a big one), up into the container, that way it looks slicker.


I love when people build stuff, that's what makes us human. Never stop redesigning

Yes its good, bad, and ugly but it works for now. I recycled a Bottle if that counts.
I knew about the sand trick for bending the tube... I used to make signs for a living, but wanted something quick.

Can't see through ABS dude, don't know when to refill it. (you could plumb a airline tube on the side of the tube
as a measuring device to see the water level)

Airline will not allow air/water exchange... I've already done it, unless you do a Sun Tea Jar type.

I'll prob improve the design later, but right now it's to keep me from filling that tank so much during the summer
(even right now)

Afterall, this didn't cost me any $ (wife likes that vs buying a ATO for $80). Thanks for the fancy ideas Sam, nice to know there are other DIY people around here.

Ever tried to build a DIY Reef Surge device, I did it was hella funny, fun to make too (out of toilet parts)

[sandiegan]

I guess nothing can displace experimental data, but that was the reason the Sun Tea jar was setup in that way. One thing that would be cool is to set up a system just like yours and minimize evap on all of it. Then we could measure the salinity of the "fresh" water over certain intervals.

All I was relating was anecdotal 'facts' that were told to me by a pretty prestigious member of NR. Glad it works out for you though.