As I mentioned in someone's thread, we did a full pond clean out this weekend on our 13 year old pond. We've never cleaned it or vacuumed it - just keep the leaves scooped as needed. We were experiencing a lot of floating debris and cloudy water any time we had a hard rain so decided it was probably time. For reference we also have never done water changes - just rain or hose fill ups as needed.
We bought an inflatable 360 gallon pool for a temporary fish holding tank and pumped it full of pond water. Then we pumped the pond down to even the playing field between me and the fish - those suckers are fast! We have mostly goldfish and shubunkins, just one big koi. I caught the fish and my husband transported them to the pool. That probably took us a half hour. 42 fish came out of the pond into the pool.
Then I started at the rain exchange and power washed the gravel until there were no more areas holding dirt. Obviously we were washing the dirt down into the rain exchange, so we would periodically start the pump to pump all the dirty water out of the reservoir and into the pond. Once we could see that the water was pumping clear we felt confident the rain exchange was reasonably clean.
Then I moved to the top of the waterfall with the power washer and just blasted away - a good amount of dirt and debris was caught between the rocks and in the pooling areas in the waterfall. Slowly worked my way all the way to the base of the waterfall and just kept rinsing everything down into the pond. At the same time, we continued pumping the water from the pond down the storm drain. Worked great. We had a hose running in the rain exchange the whole time, so every time we got enough water in the reservoir to run the pump we turned it on and that help rinse the dirt and debris off the waterfall. I lost count but I think we filled and pumped it out 5 times total.
Once the waterfall was clean I started on the main pond. I moved my lily and lotus pots out of the way and removed our "fish cave" (a clay chimney liner) from the pond completely. As I had often suspected, the cave was full of gravel - the fish love to move it around and had made themselves a nice little cache of gravel to pick through inside the cave.
For the rock walls I just power washed the surfaces of the rocks, rinsing off the dirt. The algae does collect a good amount of silt but it was easy to rinse it down. I made no attempt to remove any of the carpet algae from the rocks - that stuff took power washing like it was actual carpet. I made a concerted effort to power wash between the rocks - which was the topic of discussion on another thread... how much debris collects between the rocks? My conclusion: there was nothing. The water ran clear from behind the rocks . We do have some plant growth between the rocks which obviously holds dirt, but anywhere that it was just rock butted up to rock there was nothing to wash out from behind the void. When we built the pond, we filled behind the rocks with gravel.
Once the walls were done, I moved on to the pond floor. My approach was to move as much gravel as possible to the two ends of the pond and just keep rinsing it with the power washer. The pump was at the lowest point of the pond near the middle, so the dirty water kept flowing downhill to the pump. I rinsed and shoved gravel around until it was as clean as I could get it and the water was basically running clear. There was a lot of mulm - broken down organic matter - but nothing sludgey and absolutely no stink whatsoever. The power washer did keep blasting that silty mulm back on the walls so I did a great deal of re-rinsing to keep that moving down to the pump. I was about 90% done with the bottom of the pond when the pump just stopped working. (I blame my husband who kept saying "EVERYTHING IS GOING EXACTLY TO PLAN!" Haha.) We had borrowed the pump from a friend, so we knew if it was broken we'd be replacing it, so my husband ran to the local big box and bought a replacement - the new one ran for less than an hour and IT QUIT. So don't buy a Barracuda pump. We have a small submersible pump so I had gotten that out and hooked up while he was sat the store, so I used it to keep pumping out the dirty water while I waited for him to get back. That one has a garden hose out put so I used it to water my potted plants. Slowed me down a big by didn't stop me. I knew we needed to get the pond filled and running so the fish could go back in the next day.
Anyway after the second pump stopped working, I limped to the end with the small pump (which by the way we bought more than 30 years ago and it STILL WORKS GREAT) and was able to pump down to where I could see bare liner at the lowest point and only clear water. I spent a bit of time repositioning some lights, put the fish cave back in the pond, dropped the potted plants back in and we started filling the pond back up. I did add pond dechlorinator to be on the safe side, even though we were going to let the pond run for 24 hours and probably would have been fine. WE have chlorine in our water, but no chloramines.
It was a satisfying day's worth of work. None of it was hard, but it was a lot of climbing in and out of the pond - which is far easier with no water in the pond. It was so cool to see the rocks that we put in the pond all those years ago still firmly in place. The construction has held up remarkably well for a family who had no real idea what we were doing. Seeing some of those rocks again was like visiting old friends - I know... I'm nuts. But when you hand place tons of rock, you get kind of attached!
The next day we returned the fish to the pond - much easier to catch them in a 350 gallon rectangular pool with no place to hide. 42 fish came out of the pond; 41 went back in. I had netted the pool overnight, but we had set up a box filter with a small pump to keep the water moving so I had to leave a small area for the water to flow back in. One of the goldfish decided it was a good opportunity to take a leap... not a good landing for him. As of this morning all the fish are swimming happily in their now much cleaner home.
So that's my pond clean out saga. Would I do it again? Maybe. It is satisfying to get rid of all that dirty water, but I don't think that the dirt would ever cause a problem. It's not like it was building up on the bottom or anything and the fish certainly didn't care. But it did satisfy my curiousity and hopefully we won't get the clouding and have reduced the floating particulants dramatically. Now I'll be curious to see if we get "new pond syndrome" - green water? Lots of string algae? STAY TUNED!
