Filtration system

[kenb]

I have been using Blagdon pond filter which may be too small in capacity to keep the pond water clear. I estimate the water volume about 5000 litres and there are about 30 goldfish which multiplied from six despite previous green opaque water
The pond is shaded only in the afternoon.

I recently drained and cleaned the liner snd refilled with rainwater. The water has recently started to become cloudy despite clear water recycled from the filter. The pump runs continuously.

The filter traps large amounts of green matter which I clean when the the filter overflows from clogged filter pads.

The base of the pond and objects within are covered with green deposits.

i think the system is inadequate but choosing a suitable filtration system is difficult as there are so many to choose

I welcome members recommendations.

 

[mrsclem]

When you cleaned your liner you removed all the good bacteria so basically you are starting all over. Give it time!

 

[JRS]

Welcome to the forum.

Looks like some good sized fish. Rehoming some would help to reduce the waste which fuels the algae. Seems like you have a tight space there, with the tracks, but I have had great success with a small bog filter next to my pond to eliminate green water.

The other option would be to use UV, some filters have it built in, to kill the algae. I prefer a bog which can be as simple as large pots filled with plants and water flowing through it since it gets at the root cause of the issue.

Looks like you get a lot of sun also?

 

[j.w]

@kenb

 

[JRS]

Missed your afternoon shade description; best time to have it I think, cuts down on the heat in the summer.

Goldfish will also eat a large amount of algae on the substrate if they are not getting a lot of prepared foods. Some have reported great improvements with algae after reducing or stopping feeding altogether while the goldfish remain fat and happy. And overall, nutrient reduction should help the green water situation also.

What model of Blagdon filter are you using?

 

[kenb]

When you cleaned your liner you removed all the good bacteria so basically you are starting all over. Give it time!

Agree although it was done in ignorance.

 

[kenb]

Missed your afternoon shade description; best time to have it I think, cuts down on the heat in the summer.

Goldfish will also eat a large amount of algae on the substrate if they are not getting a lot of prepared foods. Some have reported great improvements with algae after reducing or stopping feeding altogether while the goldfish remain fat and happy. And overall, nutrient reduction should help the green water situation also.

What model of Blagdon filter are you using?

Many thanks for your advice. Hadn't considered possibility that goldfish consume algae.

I have been feeding with Tetra variety sticks which the fish devour in a frenzy. I'll see what happens if I stop for a while.

 

[kenb]

Welcome to the forum.

Looks like some good sized fish. Rehoming some would help to reduce the waste which fuels the algae. Seems like you have a tight space there, with the tracks, but I have had great success with a small bog filter next to my pond to eliminate green water.

The other option would be to use UV, some filters have it built in, to kill the algae. I prefer a bog which can be as simple as large pots filled with plants and water flowing through it since it gets at the root cause of the issue.

Looks like you get a lot of sun also?

Many thanks for your thoughts.The Blagdon filter is for a minipond and has a UV filter. It traps green algae very efficiently and I need to clean the filter pads every 3/4 days.

Interestingly I took samples of water discharging from the filter and directly from the other side of the pond. I was surprised to find that both were equally clear and overnight precipitated some green matter on the base of the jars.

Recently the fish have become more visible and I am starting the think that the system is perhaps adequate.


Is the green build up on the substrate and rocks normal or should I install a filter for a larger volume pond of say 6000 litres? I have read that frequent filter cleaning (using pond water) is symptomatic of insufficient filtration capacity.


Don't have the pleasure of too much sunshine. This is England although experiencing a heatwave at present.

 

[JRS]

A short layer of green/turf algae growing on the rocks and substrate is a normal feature of a natural pond and is to be desired compared to green water. It helps use up nutrients like the suspended green water algae without ruining the view through the water. If it all possible, try to get some more live plants in the system along the edges or some floaters which will also help use up the nutrients fueling the algae.

A larger filter will help filter out more particulates and if a larger UV bulb can help kill more of the suspended algae. Filter volume capacity listed by the manufacturer is often optimistic and once it is in use can fill/clog quickly resulting in the reduced flow you have seen so larger may help in that aspect. Over filtration never hurt as long as flow rate is not too much for the livestock.

 

[kenb]

A short layer of green/turf algae growing on the rocks and substrate is a normal feature of a natural pond and is to be desired compared to green water. It helps use up nutrients like the suspended green water algae without ruining the view through the water. If it all possible, try to get some more live plants in the system along the edges or some floaters which will also help use up the nutrients fueling the algae.

A larger filter will help filter out more particulates and if a larger UV bulb can help kill more of the suspended algae. Filter volume capacity listed by the manufacturer is often optimistic and once it is in use can fill/clog quickly resulting in the reduced flow you have seen so larger may help in that aspect. Over filtration never hurt as long as flow rate is not too much for the livestock.

Many thanks for your advice. Reassuring to know that green algae deposits normal and desirable. Also on confirming benefits of a larger filtration system.
Ken

 

[GBBUDD]

it would appear to me that you have too many fish. though you were smart not throwing koi in there as well . i'd lean toward thinning the herd . get a new filter one that claims it is big enough for your pond and keep the old one running as well

 

[kenb]

it would appear to me that you have too many fish. though you were smart not throwing koi in there as well . i'd lean toward thinning the herd . get a new filter one that claims it is big enough for your pond and keep the old one running as well

Agree. I'll contact Waterworld to see if they might take some. The jars contain water samples both from the pond and from the filter outlet. They are more or less identical although more algae has settled in the pond water jar on the left.