Thursday, July 21, 2011

The Bog Filter – Day 1

It all started with a bird bath. In an island. Full of mosquitoes.

We inherited a bird bath from the previous owners of our house. It was located in the front yard in a patch of land we call "the island" because it is surrounded by a ring of asphalt driveway. Over the years the bird bath saw lots of use – from crows cleaning their roadkill prizes to winter juncos taking an icy dip. Every winter we kept it clear with a heater and throughout the summer we cleaned it constantly; it was always filling with algae and in just a few short days, mosquito larvae. Hence the progression of events you will read about here.

One summer we had a great idea; if only we could keep the water moving then mosquitoes wouldn't like it and there would be no more larvae (nice in theory anyway). We bought a small fountain pump and sprinkled the feeder with decorative rocks. It looked nice but it usually plugged with algae or gunk in just a few days, and then the larvae would return. Arrrrggh! Still, we pressed onward.

The next great idea, one that we actually stewed on for a few years, was the thought of a big fountain in the island – a la Longwood Gardens! If the little birdbath kept getting mucked up, why not scale up the mess? That would involve digging a big hole and for quite a while I wondered if I could get someone in with a backhoe to do the job. Not wanting to pay anything for the work, or at least very little, that aspect of the job went nowhere fast.Soon another bright idea came along. Since I play the tuba, why not find an old tuba and make that the centerpiece of the fountain, complete with water from the bell? Sure – no problem. I took a few turns at the ebay musical instruments listings, but all the old tubas there, some almost crushed beyond recognition, went for way too much. Once again, this idea seemed DOA. But not to worry! Pat had mentioned my “need” to her colleague Eleanor at work, and one weekend we got a phone call; “I'm at a flea market, and here's a tuba. The guy wants $100 for it. Do you want it?” she asked. We asked Eleanor to bargain the guy down and hung up, not knowing what had happened. That Monday at work, Pat was presented with a Getzen contra-bass bugle, a type of tuba used in early marching bands. Now we HAD to build the fountain.
So a great hole was begun. Initially, it was only going to be as big as an old baby pool, about 5' diameter and 8” deep. Once that goal was reached, well, I just kept digging. Eventually the baby pool went into the bottom of a 7' diameter by 18” deep pit. A plastic liner was added, then water, then the tuba, then lights. Now everything was in place – the water was clear and everything looked great. But soon the mosquitoes found the pool and everything started wriggling with larvae.
So next came 29¢ goldfish – a whole bunch of them. They had a ravenous appetite for mosquito larvae and that problem quickly cleared up. BUT – and here's the catch and the first real reason for the bog filter – the fish food caused an increase in nutrients and we suddenly had an algal bloom. Next step was algicide but all that did was create a sludge of dead algae and the growth quickly returned. Then we saw a water garden cleansed by a bog filter and we were sold. By then it was fall though; it would have to wait.

So now this bog filter story begins...but first, a few “before” pictures. Here's the tuba fountain with our house in the background:










And here's Maya enjoying the yard, and one of the current pond inhabitants.






































So here are the parts for the bog: cinder blocks, liner, a pump and tubing for the under-gravel filter. The gravel will come after everything is ready to go.