ulladubulla ulladubulla
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  • Joined: 14/3/2009 22:33
  • From Nottinghamshire
  • Group: Registered Users Basic Membership
  • Posts: 1
  • Posted on: 13/9/2009 17:45
Filter and pergolas! #1
We are fairly new to all this so here is what i have at the moment, and a few questions -

1800l pond in an L shape approx 750mm deep

Blagdon midipond 4500 and pump. Blagdon Airpump and 2 no airstones.

8 goldfish and 2 small koi.

We are happy with the size of the pond (although i have toyed with the idea of raising it to make it deeper) and appreciate we may be overstocked but could you offer any advice please?

We have recently halved the size of the bordering hedge and as a result have suffered intermitantly with green algae (from the increased sunlight?). I have also lost a number of this years fry and a couple of larger goldfish to herons. My first question is how effective would a pergola be in cutting down on algae and also rendering the pond a bit more inconspicious to the passing herons?

Also i have around ?300 to upgrade the filter. What would be the best solution for this size of pond as we want it to be as effective as possible?

We are also toying with adapting an adjoining raised to form a second small pond falling into the larger one. We have noticed on a number of the other users ponds that you have pre formed metal gates for the water to fall between the two ponds. Are these available to buy online?

gazza67 gazza67
  • Not too shy to talk
  • Not too shy to talk
  • Joined: 13/5/2009 15:24
  • From Devon
  • Group: Registered Users Basic Membership
  • Posts: 27
  • Posted on: 13/9/2009 19:33
Re: Filter and pergolas! #2
Hi not an expert but:

1,Get a UV light to clear the green algae, i personally rec a seperate one, not one that comes in a filter.
2,The pond is not deep enough for Koi, a minimum stated here is 1 metre deep for koi.

Apart from that, i'll leave it to the experts. ;)
RedHeadPeter RedHeadPeter
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  • Joined: 30/3/2009 17:47
  • From London
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  • Posts: 20
  • Posted on: 14/9/2009 10:29
Re: Filter and pergolas! #3
Agree with gazza67 - a good UV filter is a must!
I had lots of problems with murky water until I changed my filter earlier this year for an Evolution Aqua EazyPod. Transformed the situation. It is, though, quite a big beast and light grey in colour so you would probably want somewhere to hide it!

Do you mean to build a pergola over the pond - or part of it? Cutting out sunlight should help with green water problems, but UV filter should be first step. But it will only help with heron problems if you cover it completely, which I guess you won't want to do. Others have managed to deter herons with trip wires round the pond made of fishing line - I also have fishing line strung back and forth over the pond.

750mm is not very deep. And 1800l not a large volume so deepening the pond could be a good idea - but at the same time it doesn't seem overstocked. My pond is about 2800 litres but I have 3 large ghost carp (9 inches maybe), about a dozen blue orfe and a dozen other varied species. I don't see the point of a pond with just a couple of little fish in it! As long as they get plenty of oxygen and the filter can cope with the waste they should be fine.
BigKev BigKev
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  • Joined: 31/8/2007 9:17
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  • Posts: 108
  • Posted on: 22/9/2009 10:56
Re: Filter and pergolas! #4
The Blagdon Minipond filter should be fine for a pond of that size. the built in UV is adequate, however, the Minipond pump isn't brilliant as it is not a waste handling pump. I would use a Hozelock Titan (actually I do).

Are you sure you have algae problems? Can you describe exactly what you see or even post pictures? A green tint can also be down to excess nutrients in the water. Take out a pint glass of water, if it looks totally clear, it's most likely the excess nutrients causing the green hue. A bacteria boost from Hydra Aqua clears that quickly (from experience). If there are very small particles, it may be down to the newness of the filter (at the time of writing, they have only been out a couple of months) as the foams are less efficient when new. They need to build up a little dirt before they are working at 100% efficiency. Again, Hydra Aqua do an extra fine electrostatic filter layer that you can use to boost the efficiency of the filter.

A pergola will help with the dreaded blanket weed. I have had no blanket weed since fitting mine. It will also keep Herons away. Not sure if it will help defend against a Heron that already knows of the pond's whereabouts though.

I would save the ?300 you have for a filter upgrade as I have found the Minipond to be a brilliant filter.