so i'm setting up my 10g in my office and needed a simple and cheap drop checker for it. so i went to wall mart... and this is what i ended up with.
the very first thing you need is some whisky.
the pen's cost me $1.00 (two in a pack) and the suction cups cost me about $1.50.
you'll just need the cap!
remove the suction cups hook by sliding it through the hole it is in and slide the cap's clasp into it
heat the plastic around the opening of the cap so you can slowly bend it inwards
heat some airline tube and bend it out
jam the tube into the cap. you'll have to heat and reheat a number of times to get a seal, be careful as the plastic on the cap like to adhere to items
works great i guess... just put it in, no co2 being added to the tank yet. I should probably cut back the airline tubing
my next attempt with this will probably be using a dremel to slice the cap in the center so that it is shorter and getting the items together without a butane pen torch