DIY Airlock for the apple cider

I sure hope the first batch of apple cider turns out well.  It's used a lot of balloons!  I've only been able to re use each balloon twice.  The balloons filled up so quickly.  Here's one at three hours after "burping" (removing the carbon dioxide).

DH suggested checking some of the shops that sell brewing supplies and just buying an air lock.  They are supposed to be quite cheap. 

They probably are if you can find the shops close by.  The two that we knew about are now closed.  I guess there just are not enough home brewers to keep them in business. 

At the price of gas we were not about to go any further away from home.  So DH checked a few YouTube videos and came up with his own version.   A piece of plastic tubing, the cap for the juice bottle, and a water bottle.  That's it.

He drilled a hole into the juice bottle cap.  Inserted one end of the plastic tubing into that hole so it comes out the bottom by about a 1/2".  The other end of the plastic tubing goes into the cap of the water bottle.  The tubing reaches to about 2" from the bottom of the water bottle.  The bottle is then filled 3/4 with water.  Several small holes drilled into the cap allows the gas to escape. 

The gas leaves the juice bottle through the tube, into the water bottle.  It then forms a bubble in the water that rises to the top.  The gas then escapes.  The water keeps air from entering the juice bottle through the tube.  That shouldn't be a problem until the fermentation process stops producing the carbon dioxide.  But if we're not around when that happens, the air could get in and spoil the cider.  At least that's how the process was explained to me.  If we've gone through all this for no reason......