Gravity Fed ATO

[thesmallerthebetter]

I APOLOGIZE IF THIS IS ALREADY OUT THERE SOMEWHERE....

 

So, ive got a couple PM's and such reguarding a gravity fed/hamster bottle ATO system. the beauty of these things is that theres no moving parts, no electrical connections, nothing. just raw fluid mechanics and physics.

 

the concept is similar to the way water stays in a straw when you put your finger over the end. Theres no air pressure pushing down so no water comes out. so in a sealed bottle, if the water line in the tank is higher than the submerged tube, then no water can get out cuz theres no downward pressure. get it? lol, its tricky.

 

theres a thread out there with a version of it that uses one tube to take air into the jar and another to deliver the water to the tank. i dont like that model cuz it has to be really airtight and whatnot. harder to make.

 

the components of the one i made are as follows:

 

1 glass (rigid plastic would work) hamster bottle with a plastic lid (it had a metal cover over it so if you are looking to get one, play around with one to see if it has a plasitc top under the metal)

a length of ID tubing that fits into the opening of the bottle (actually a little bigger to create a seal)

some zipties

a clip from a cellphone headset or a TV mixers box (in my case), a wooden closepin painted black would work on larger tanks.

 

if you cant find a bottle with a plastic lid, find a stopper that fits in the opening and drill a hole for the tubing.

 

i only have final pics cuz mine is already built....but ill build a new one in a few days for a different tank and upload build pics.

 

instructions:

 

thread the tubing through the lid/stopper you are using for the bottle

Cut the part inside the bottle lengthwise (otherwise bubbles get stuck)

zip tie the tube to your mounting clip (loosly as to not restrict flow)

fill with water

mount above the tank

adjust waterline accordingly

 

TADA!!!! you have the most accurate ATO on the planet.....

 

i use mine on my halfgallon pico (houses Acropora and other SPS) and it works wonderfully.

 

 

 

 

[BKtomodachi]

I have never understood how these don't just flush the fresh H2O in due to osmotic gradient.

[thesmallerthebetter]

I have never understood how these don't just flush the fresh H2O in due to osmotic gradient.

 

my understanding is that osmosis needs a membrane....no membrane here. and freahswater and saltwater dont like to mix, just like water of different temperatures. the ocean is full off temp/salinity breaks (great places to fish!!!!)

 

[Justin_Freebords]

sweeeet ive been looking to do this on my tank. Would you mind post a picture of the bottle attached to your tank?

[BKtomodachi]

my understanding is that osmosis needs a membrane....no membrane here. and freahswater and saltwater dont like to mix, just like water of different temperatures. the ocean is full off temp/salinity breaks (great places to fish!!!!)

 

well regardless of the presence of a membrane, there is a solute gradient, right? And if you were to say that water "likes" anything, it would actually "like" to mix the FW and SW.

[Justin_Freebords]

in defense of this post and the question of what i think is "wont the salt water go into the freshwater bottle?"

 

I saw a post by someone on a forum, maybe here and they tested it for a week in a bowl with food coloring and none of the color at the end of the week had gone into the water bottle

[thesmallerthebetter]

in defense of this post and the question of what i think is "wont the salt water go into the freshwater bottle?"

 

I saw a post by someone on a forum, maybe here and they tested it for a week in a bowl with food coloring and none of the color at the end of the week had gone into the water bottle

 

you beat me to it.

 

i tested the salility of the bottle water today. totally fresh. if there is a solute gradient its negligible.

[BKtomodachi]

i tested the salility of the bottle water today. totally fresh. if there is a solute gradient its negligible.

No single person has explained this yet.

 

I want ANSWERS people.

 

There is a solute gradient, and its fairly substantial.

[freddy4130]

Coolest bottle EVER!

 

 

http://mysigg.com/index.asp?PageAction=VIE...&ProdID=466

[thesmallerthebetter]

Coolest bottle EVER!

 

 

http://mysigg.com/index.asp?PageAction=VIE...&ProdID=466

 

 

lol, spray that $#!+ black and it would be rockin

[freddy4130]

^^^Spray ANYTHING black and it would be rocking. BTW, they have black ones, that red one just happens to be the largest. It is 50 oz. and the rest are like 30 and 20. They even have ones with skulls, LOL.

[yellowslayer13]

For the osmosis you need a membrain to tranfer the sodium chloride molecules. Also can we get a better pic of that first shot?

[filefish949]

For the osmosis you need a membrain to tranfer the sodium chloride molecules. Also can we get a better pic of that first shot?

 

 

wut's up n00b?

[RBTAGL]

membrane or lack there of has nothing to do with it. there is a salinity gradient which will lead to a tendency of the fresh and saltwater to mix...however, there is also a density gradient which causes freshwater to "float" on top of the saltwater,and is stronger. There will be a mixed layer of brackish water at the lower end inside of the tube, but the fact that the bottle is above the tank helps to maintain the seperation.

[stan-o]

Hey guys, I'm trying to build one of these but I'm not having much luck. When I fill up my bottle with water and turn it upside down, nothing comes out unless I squeeze the bottle. One note is that my tube does not protrude into the bottle because I'm using a john guest fitting. Do I need to change that and have the drain tube higher than the lowest point?

 

Thanks

Stan-O

[evilc66]

Your tube may be too small.

[freddy4130]

What evil said. Your tube must be large enough for water to exit and air to enter.