How can we clean up the pond bottom? - sludge and algae

[Ponds R Cool]

We have two ponds - 1 x 3600l and 1 x 1800l. Water travels from top (4m x2.5m) pond to other (2m x 2m) pond via a sml river, then returns via pump and underground pipe through UV filter back to the top pond. Had a green water problem which we treated successfully with barley straw extract (the water is now crystal clear) BUT there is still the algae and sludge coating all over the rocks and stones in the bottom plus the algae is attaching to the pond plants. So far bought two venturi type cleaners, one attaches to the garden hose and the second pump action type (designed for spa pools). They are incredibly slow progress; do not "vacuum" the bottom very successfully and their filters are not that fine. Most successful fix we have done so far is with a home made filter made of sponge rubber bricks at the end of the river that "catches" what you stir up before it hits the bottom pond, but looking for some better long term way to keep the rocks/stones/bottom attractive looking. Any suggestions?

[suphew]

Your UV filter shold be taking care of the green water, and to a degree the the other algae as well, have you changed the bulb resently?? They only last a year or so.

There are a number of other things you can also try to lessen the amount of algae. Water changes, through a bit difficult with that much water. Lots of plants, they will use the nutriants that the algae is currently feeding off, and shade the water stopping the algae getting so much light. You could also add a filter to the input of your return pump, this could be as simple as a plastic container (ice cream container? but the bigger the better) with holes drilled and full of filter wood or sponge or some other filter media.

If your unable to syphon the crap out from the bottom of your pond I can't thing of many ways to clean it out. You could empty each pond, one at a time leaving a few weeks between. Or use a pump to suck all the stuff out. But my pick would be to add lots of plants and call the crap on the bottom plant food.

[alextret]

Is it possible to evacuate all water, dry the pond bottom, clean it, refill again ...

[Mark]

i agree with the last reply the best way is to empty the pond. My pond is about 4mtrs by 5mtrs i need to empty it every second year to keep it reasonably clean. I have hired a large pump to drain it but the fish dont come out the other end in very good shape. So next time it will be a smaller pump then you need to sweep the crud of the bottom with a plastic shovel and brush. Takes time but its the only fool proof way to keep the pond from going green in the summer. Best to do this before the fish start breeding like next month at the latest. My pond has a liner so barefeet only when i get in to clean it.

[sharn]

i remember one year during out first pond clean i decided to hop in in my gummies, needless to say i landed on my rear extremely fast and it was quite painful too. mum thought it was hilarious much to my disgust so now i bribe the little sister to do it :lol:

[fishboi]

ur water should be clear with the UV-C light so like suphew said how old is it?

just wrote a long post about how to get rid of hair algae hope it helps

http://www.fnzas.org.nz/fishroom/help-a ... 15798.html