I had a complicated day where nothing went quite right.. I got lots done, but nothing came out as well as it should have.. so.. by the end of the day i was pretty beat.. it was about 90 degrees, I was hot and tired and looking for something useful to do.
The looming problem of the week has been our pool. It's been losing water at rate of over 600 gallons a day .. yet we couldn't find the leak. I'd re-tighteed all the pluming and searched the sides of the pool carefully for a leak.. no luck.. Then , this morning. Diane noticed a wet spot under the deck… .. I decided to check it out.. Indeed.. the ground was wet under the deck, but there was no visible leakage form the side of the pool.. the soil was only wet in a narrow band.. so I decided to look inside. I put on some goggles and dove to the bottom.. darn.. I couldn't see well enough without my glasses.. so I stuck them on top of the goggles.. I looked ridiculous.. but at least i could see.. I searched up and down the walls of the pool.. but nothing looked obvious.. Then I started thinking about how I'd find a vacuum leak.. When I was at MIT we'd use a variety of techniques to find leaks in high vacuum systems.. we'd hook up a mass spectrometer to the vacuum system then walk around with helium tubes squirting around joints.. when the mass spec detected soemthing.. the joint you were squirting was bad. I've seen them do soemthing similar with car air conditioning systems.. thought there you use colored smoke.. and pressurize the system with it and look for smoke ..
So I asked myself.. what would work like smoke under water.. ah-ha… an idea.. I grabbed a bottle of blue food coloring and dove back in.. I squirted it around the seams.. but it just dissipated.. I tried some of the creases on the bottom… then I saw a funny discolored space.. it was right under where the ladder usually is.. BINGO.. the dye got sucked into the hole.. by the speed of it.. there must have been a pretty sizable stream of water leaving the floor of the pool about 12 inches in form the side where the wet spot was.. I felt like Sherlock Holmes !

I wanted to get a picture of it to show diane.. so I rummaged around and found gabes underwater go-pro… curses.. the battery was dead.. and i couldn't find the charger.. not to be deterred, I took the battery out and grabbed a power supply from my lab. dialed in the voltage of the battery and clipped into it.. I charged it for about 15 min.. Then I clipped it together and took this movie.. you can see the dye get sucked into the hole..

 

I found soem underwater vinyl patch , cut it out, coated it with goo.. folded it in hal then exhaled all the air in my lungs and sunk to the bottom of the pool.
I opened the patch and quickly smoothed it over the hole. Then I put a nice piece of marble on it to help i stick.. (note: The marble happened to be the splatter guard on an old urinal.. Don't know why I added that detail.. but you have to admit it was interesting 🙂

so.. I accomplished at least one useful thing today..

lets see if it holds !

nght all. night sam
-me