It's magical and mysterious. That's mostly because I'm too lazy to find out how it works--it's enough for me that it does work.
Here we have springtime algae soup. Green, yucky, visibility about six inches.
Of course, if I could have seen down further I would have just seen the black liner.
But eventually I couldn't stand to look at it any more so I drained it and added fresh water. It looked clear for three whole days before it turned into green algae soup again. It looks fairly clear here, although a bit cloudy, and I began collecting rocks to finish it off into the mountain pool of my imagination.(If all this sounds vaguely familiar, it's because I posted my photos a couple months ago.)
I found time to get the filter working again after the puppy tore up the media. At the very top of the filter is a bundle of barley straw doing its magic...
Behold, this is my pond at the summer solstice.What a change--crystalline! The doggies think this is the best water dish ever, obviously. The robins love to splash in the shallows and every bird in the neighborhood drops by for a sip. The newly-acquired water lilies are flourishing. It's time to sit back with a cold lemonade and just enjoy the ambiance.
Thank you, barley straw!