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$15 Gravity driven auto top off system


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At the meeting we discussed auto top offs and I brought up the gravity driven auto top off which is a good choice in certain situations like when you have a small tank or a large area for your sump, or don't care about looks. Oh and also its dirt cheap and probably one of the most reliable systems. I just constructed a super ghetto auto top off system for my super ghetto frag tank and thought I would post how it is done.

This auto top off has a snail guard, quick connects, and adjustable water level latch. If you don't include these extras you can build this for 8 bucks. But as is it is $15 dollars.


2 1/4" quick connect to 1/2 screw in adapters - $3

2 1/2" straight to 1/2" screw PCV adapters - $.50

a foot or so of 1/2" PVC -$.25

1/4" tubing of choice, I like poly tube as it rigid and good for going through stoppers. $3

Number 10 stopper from the home brew store $1.50

5 gallon water jug from H.E.B $5

2 1/2" PVC snap tub holders $.50

1 blue PVC electrical outlet box(Perfect snail guard) - $.36

1 suction cup thing from a power head - $?


Drill with 7/32(the one right below 1/4) bit

number 3 metric alan wrench for pushing tube through stopper

silicon sealant

pvc glue



Step 1.

Drill two holes through stopper with bit. You want the holes to be as close to air tight as possible so drill with a smaller bit then lubricate the holes with olive oil/mineral oil and put alan wrench through hole. Place tube over end of alan wrench and push through. The alan wrench will give you nice leverage so the tube should slide right through. Run one tube long enough to reach the bottom of the jug, and the other just long enough to get through the stopper. Wipe off oil and seal the tubes to the stopper with silicon. You can attach a piece of spare PVC to the siphon tube so it stays at the bottom of the jug. Note: you can also just use rigid tubing to go through the stopper but, eh, I didn't have any.


Final stopper assembly


Step 2.

Assemble snail guard and water level control. Attach suction cups to the back of box. In my case I just made two cuts and slide the suction cup block on the box. Attach the two 1/2" PVC tube holders to the inside of the box. Assemble 1/2" PVC, quick connectors and caps into one short tube(siphon output) and one long tube(water level control). When you are done it should look like this.



Step 3.

Fill Jug with water, place above sump or in this case tank. Set water level by moving water level control tube up or down to the desired level. Snap holder shut. Connect everything and start a siphon with the siphon drain tube and quick connect it to the siphon drain pvc connection. Bam! your auto top off is running. Snails can't stop it, You can adjust water level control just by moving the PVC tube up and down, and it almost never fails. Some things to watch out for. Make sure you run the water level control tube long enough or high enough such that the vacuum created by the siphon can't draw water up the water level control tube. Make sure your jug is placed high enough such that your siphon is strong and won't break by sucking air once the vacuum in the jug is created.


I hope someone finds this useful.

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