Cleaning out the Fish Pond

We have a 2000 gallon fish pond in our back yard and today we cleaned it. This is something we do once a year (thank goodness), essentially flushing out the old water, getting most of the sludge out and getting the algae under control (we hope).

Last year was the first time we cleaned it and the results were pretty good. But we still had a lot of "crud" built up in it. The procedure is to disconnect the circulating pump and use it to empty out the pond. When the level is low enough, we collect the fish (easier said than done) and place them in a holding tank which has been filled with some pond water. We have two very large koi, and they were hard to catch, so we left them in (a mistake in the end).

Scrub the rocks. This year I used the grill scraper. Worked great!! So much better than a Scotch Brite pad. Rinse. Pump out the pond. Rinse again. Pump again. Remove sludge - I used an oil spatter guard - you know, those circular mesh things you put on top of your frying pan to prevent oil from spattering all over the stove and house. That was a yucky job. But when it is done, you can see the rocks at the bottom of the pond again.

Then fill with fresh water. Here is where things started to "go bad" for the two koi. Last year, we got them out and they stayed in the holding tank. The fresh water is from the tap, so there is chlorine, etc in it. Once the water reaches a certain level, we add some pH adjustment chemicals and turn on the recirc pump, which addes oxygen to the water. Last year, we waited until the fresh water had been circulating for quite some time before adding the koi back in. Well, our two koi which stayed in the pond during the cleaning didn't take well to the fresh water - I think there wasn't enough oxygen. So we now have two dead koi to have to deal with. Great.

On the upside, the pond looks great. The goldfish are doing OK (for now - Scott added them in while the fresh water was being added, which may have been too early - I hope they survive!). Note to self - make sure to get the fish out and don't add them back in until the new water has had time to adjust.