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Submerged pond pumps/filters

We noticed that our pond stream was running slower than usual - we think the cause may be the submerged pond pump is partially blocked - how often to you clean your pump? We have turned it off at the mains for now, until we can solve the problem.


  • Pete.8Pete.8 Posts: 10,953

    Assuming it's not a filter that needs cleaning, if you take the pump out of its housing, you'll probably find a lump of blanketweed or similar jammed into the impeler which is slowing it down.
    I usually manage to wiggle it out with a twig, but if you can't, then remove the impeler casing and pull it out. 

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • Thanks Guys, we will follow the instructions, and also look out for the filter, which I think is included in the pump and it is already raised, but it will be difficult to re-position the pump on the raised area as we can't see the bottom of the pond!

    I am sure it is blanket weed that is causing the problem.  I will keep you posted.

  • Yes it was a blanket weed problem.  We hoisted the pump out of the pond and filled a bucket and a half with blanket weed that was wrapped around the hose and the pump itself.  No wonder the pump was struggling to filter the water through it. 

    We took the casing off the pump but luckily there was very little weed inside it.  However we have now placed the pump on a shelf with just a few inches of water above it - so we can keep an eye on the pump, although I am not sure if this is the right thing to do.  We didn't expect to have so much blanket weed in our pond - although there is very little shade, only first thing in the morning.

    If everything had gone according to the text books, then our water would be perfect and the oxygenators would be helping to keep the pond water clear and free of blanket an ideal world!

  • FloBearFloBear Posts: 2,281

    How old is your pond GD2 (excuse the abbreviation) ? If it's in its first year it will take quite a long time to settle unless entirely filled with rain-water. Sun will react with the nutrients in the pond and blanket weed will have a field day. There are a multitude of other reasons too and even well established ponds suffer from time to time. 

    I too have my pond pump on a shelf just a few inches under the water - only needs de-clogging once in a blue moon.

    Last edited: 31 July 2017 16:29:08

  • Pete.8Pete.8 Posts: 10,953

    Moving the pump is a good idea. Especially if you intend to run it in winter. The water at the bottom of the pond is a little warmer than it is at the top and the bugs dig themselves in down there so they don't freeze, you don't want your pump disturbing this warmer water at the bottom of the pond in winter.
    The blanket weed is all part of the cycle, whilst it's in your pond it's using nutrients, so that's good and it'll die back as and when - nature doesn't read books :)
    I use a bamboo cane and twiddle it in the blanket weed (to scare any bugs out of it) then gently pull it out and leave on the pond-side for a few hours
    Consider this year a running-in year for your pond.

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • hogweedhogweed Posts: 4,053

    My pump sits on the bottom of the pond - about 3 ft down. I clean it once a year, maybe twice. It really depends on the type of pump you have. Some pumps I have had in the past have needed cleaning every month or so. A right pain. I thought blanket weed only sits at the top of the pond, not down into the deeps so would put it back down rather than near the top. 

    'Optimism is the faith that leads to achievement' - Helen Keller
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