When I awoke this morning my fish were in distress. They were very lethargic and gasping for air. A few weren't moving at all.... I really felt bad.... It was 92 yesterday and fortunately it was MUCH cooler today, in the low 70's. Even so, I needed to take immediate action. My fish had never suffered like this before due to good aeration from a venturi and waterfall. I put my plan to clear my clogged drain on hold while I figured out a way to oxygenate the water. My son suggested rigging up something and using his air compressor. I took a section of left-over vinyl tubing from my drip irrigation system, crimped one end, poked a lot of small holes in it and then attached two heavy lead weights to hold it down. The air nozzle was a nice snug fit into the open end of the vinyl tubing and black electrical tape held it in place.
He set the pressure to 18lbs and that put out a lot of air bubbles. After about 15 minutes the fish started to show significant improvement.
Now to clear the clogged bottom drain. My first attempt yesterday with the shop vac didn't work. My attempt this morning was to take the garden hose and use water pressure to blow the clog back out through the bottom drain. I disconnected a section of pipe just in from of my leaf basket in order to place the hose inside the pipe. I wrapped the hose with a rag to make for a snug fit and then jammed it into the pipe and wrapped some electrical tape around it to hold it in place. I then got into the pond and removed the mushroom shaped cap over the bottom drain in order to allow the clog to be blown out without interference from the cap.
I opened up the ball valve leading to the bottom drain and while I held the hose tightly against the pipe I had my son turn on the water. My son said he saw air bubbles and debris coming out of the area of the bottom drain. I felt great relief.
Next I had to replace the mushroom cap to the bottom drain and that required me taking another dive. Having learned from yesterday's experience my son rigged up a 5lb lead weight which I wore around my neck to counter my buoyancy and enable me to stay submerged near the bottom enough in order to line up the three pegs of the mushroom cap with the three sleeves in the bottom drain. I also borrowed my son's swimming mask this time so I could see what I was doing.... That's the 5lb lead weight in my hand. I wonder if this is how Jimmy Hoffa felt?
The pond is about 3' deep here and I'm on my knees.
After several attempts I finally got the posts of the mushroom cap aligned into the sleeves of the bottom drain.
In the ten+ years I've had the pond I have never had a complete blockage to the bottom drain necessitating me to take the actions described above and I didn't particularly want to repeat this diving experience. I had a black plastic crate that just fit over the mushroom cap of the bottom drain. I felt that if I put this over the drain, large floating plant material such as my hornwort would not be able to get sucked into the drain. I took the 5lb lead weight and attached it to the top of the crate to hold it in place and then placed it over the bottom drain.
After reconnecting my bottom drain pipe to the leaf basket and opening the ball valves I turned on the pump and was VERY pleased to see I once again had water flow
Hopefully I will never have to repeat this experience again. However, my lack of aeration equipment did bring to my attention the need to be prepared for emergencies.... And yes, I immediately took a shower....