Green Water - help!

[Austrian Fish]

Hi,

As a newbie to the forum i'm hoping you guys can help me with a big problem i have with my pond at the moment - green water.

A bit of background first.... I've already posted a bit about myself and the pond in the Introductions forum, but basically i built my garden pond in 2007. It's 4m long by 2m wide. Half the pond is 1m deep, and the rest 0.5m deep, with a shallow 10cm margin at one end, near the deck (see pic). 5000 litres in total.

I originally stocked it with 3 medium sized goldfish - 2 orange, and one tricolour. In summer 2008 we had a surprise... baby goldfish! Unfortunately i've been unable to give the goldfish away, and i can't bring myself to kill them, so now i have 170 fish in the pond - almost 1m of fish in total.

My current pump is a 2500l/h pump in the 1m deep part of the pond, with a UV filter arrangement outside the pond (right of the pond in the picture). The 1m height difference reduces the flow to 1000l/h though. This arrangement worked ok last year, but this year i have had nothing but green water despite chemical treatment and water changes.

I've been reading a lot on the internet about possible causes, and one thing i am definately missing is a biofilter. The UV filter has a small amount of lava rock in it, but nowhere near enough to process the volume of water, so i am thinking of adding a seperate biofilter arrangement now.

However. Opinions on biofilters, and how large they need to be, are many and varied on the web.

So, my question here..... is the biofilter the right way to go? If so, what size does it need to be to process 5000 litres of water with 1m total length of fish in the pond?

As i said, i'm a newbie, and to be honest the more i read the more confused i'm getting - turn over, retention times, total cm's of fish, nitrates, nitrites, plants, string algae, green water, etc, etc - it can be difficult keeping an overall perspective, so i welcome any help anyone can give me.

The only point i'm set on is that i don't want to be adding chemicals all the time to fix the problem. I'd like to achieve a natural balance.

I should also add that i'm planning on adding a waterfall and a wetlands area this year, which i'm hoping will also help clean and process the water.

cheers,

Andy.

 

[koiguy1969]

there is no such thing as too much filter...look in th DIY forum and EQUIPMENT forum for plans for a 55 gallon bio filter and 70 gallon skippy(bio) filter. both are the same basic filter just different containers, and i put a waterfall weir on the stock tank. youll not be dissappointed with these filters. balance will come in time either way, but test your water parameters,build a good bio filter,and shade the pond as much as possible, and more plants will help too; using the same nutrients as the algea. you can substitute these containers with a good sturdy plastic outdoor trash can.

 

[Austrian Fish]

Hi Koiguy,

Thanks for the reply.

So i'm on the right track with a biofilter then. The only question is the size.

I've seen the designs for the skippy filter already from this web site

http://leisure.prior-it.co.uk/build-diy-pond-bio-filter.shtml

and worked out what size i would need based on the pond size etc, and it comes out around 55 gallons.

But. I've also seen commercial solutions, like this one :

http://www.alibaba.com/product-gs/217817263/Pond_Bio_Filter_CBF_350_.html

which sell for around 50 pounds on some UK sites. This is rated for 12000 litres, and is a fraction of the size that the skippy filter comes out at.

This is why i'm confused about what i need.

I agree that you cannot have enough filter area, but i'm relatively space limited in the garden, and putting a 55 gallon barrel next to the pond is unfortunately not really an option.

I'll definately add more plants though.

cheers,

Andy.

 

[Robyn]

You should do the biofilter to deal with the fish overload... but it most likely will not fix the green problem.

It looks like you have a bit of room to expand. I would go with a spillbox type setup (I think I have my terminology right) with the biofilter , or better yet - a bog filter!

Here is a great link on the concept:
http://www.drsfostersmith.com/pic/article.cfm?aid=2153

What you do is tier your pond. Place a second pond above your first and create the bog area as shown. Have the water fall from that area into your main fish pond.

This looks quite nice and performs a few additional purposes. The nutrients that are being utilized currently for algae growth are consumed by the plants instead. The plants add O2 to the water... as does the waterfall.

Place lots of nice boggy plants in that top section, and a water lily or such in the bottom to provide shade and thereby starve the algae even more!
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BUT... as goldfish are gonna be goldfish... the exponential reproduction is going to continue. You can check with local pet shops that are privately owned (chains are not likely to be interested or have policies against it) and see if they would like to take your goldfish. If you take rather large ones in in the spring for them to sell as pond fish... they may be VERY interested. You most likely would not get money for them. You MIGHT get some credit. Does it matter? You just need to get rid of the danged things! If they can get them for free and sell them for $5 each... they are usually pretty eager. Most small time owners cannot compete with the big boys for pond fish. They cannot get high prices for pond goldfish and would pay to much for anything over 3 inches to make it worthwhile. (Retail markup in order to make money is around 200%-300% on fish.)

Also... post on Craigs List that you have acclimated pond goldfish for free. I guarantee you will have some takers.

 

[koiguy1969]

build your skippy style filter and build your waterfall around it the filter you saw is way to small if you want low maintainence and beautiful water. you can get a stock tank for a low profile waterfall or 55 gallon drum that you can hide around the corner and run some hose...check out "my 70 gallon skippy filter" for the low profile falls in the diy section here or the 55 gallon f bio filter here in equipment section... you wont be sorry!!! but if you cant access these,use the largest trash can you can, and hide nicely...store bought for the same amount of money spent to build one will no compete with in efficiency. a big enough bio filter and plant numbers will eliminate enough nutrients to starve the alge.

 

[Robyn]

Sorry...you probably do not have Craigslist. Do you have something like it? A "swapsheet" type newspaper or something?

 

[Austrian Fish]

Hi Guys,

Thank you for all the tips.

@Robyn -

Thank you very much for the link to the bog filter. This looks like an excellent idea

I'd like to get rid of some of the fish still, but certainly not all, and not the big ones! Unfortunately we don't have Craigslist here in Austria, but we do have ebay, and also some local freeads papers. I put up some notices last year in work and the local supermarket, but no one was interested. I'll try again this year.

@koiguy -

Exactly how the systems fit together is starting to make sense now. Biofilter breaks down fish waste but doesn't remove nutriants. Algae feeds on nutriants, so i need plants to remove that, and therefore starve the algae.

I'll look at the skippy thing again. I'm sure i can find some way to hide a barrel that size. Out of interest, what medium are you using in the skippy filter? For a barrel that size it's going to be expensive to fill it with conventional filter medium. Also, do you use a Venturi in your system?


I'll post the pics of the changes i make as things progress

Cheers,

Andy.

 

[BBK]

I was battling green water all of last year. Finally I ditched the small UV sterilizer and got one that was rated for 5 times what my pond is. It was crystal clear in 3 days.

 

[koiguy1969]

as far as u.v sterilizers go.. they work, but alone they are not an answer but a bandaid. i run a 9 watt tetrapond u.v for a few days, when i first open my pond; but i wait for the water to green. my nine watter clears my 1100 gallon pond in 3 days, but not alone. i have a "70 gallon stock tank skippy filter". alge is a natural cycle, a real good bio filter will prevent alge and kill existing alge by way of starvation. a uv kills it in mass quantities by burning its chloryphil out and destroying its reproductive capabilities. the dead alge clumps together and is then able to be filtered out. algecides kill in mass quantity and leave the dead alge to feed the next cycle. so they are no good.unless you want a chemically dependant pond!! so build your bio filter as large as you can, supliment it with a u.v if you like, although not necessary,and add lots of plants and you will enjoy a happy healthy pond with low maintrainence. THERE IS NO SUCH THING AS TOO MUCH FILTRATION. and microbelifts pl. gel filter innocculant is thee best beneficial bacteria for starting up new filters. its builds a strong colony af bacteria up to 8 times faster than most. a good bio filter will most certainly cure/prevent green water

 

[Austrian Fish]

Hi guys,

It's been a busy week since i last posted. It's hardly stopped raining here almost the whole week, and a lot of places have been flooded, but luckily i'm ok, and i've been able to do some work in the garden.

So, i found out that the UV lamp was broken (it looked like it had exploded when i opened the housing up!) so i've replaced the 7W bulb with a bigger 11W one.

I'm having a very hard time sourcing connectors and valves for the skippy filter, but i was also getting frustrated at the time it was taking, so i've made a 'quick and dirty solution'. I've taken a large plant container, tipped it on it's side at 45 degrees next to the pond and supported it so it doesn't fall over, so now i have a small waterfall.

Then i've taken the return from the filter and placed it in the bottom of the container. Then i took all the old broken ceramic plant pots i could find and smashed them into little bits and filled the container with them.

The water has to go through the the ceramic so the bacteria has some place to grow.

This has been running for a couple of days now. It might be my imagination, but i swear the water looks cleaner already.

I had also made mistakes on the connection to the filter (The connector is a cone for different sized pipes, and i hadn't cut off the smaller sizes, so i was restricting the inlet and outlet flow to 1/4" instead of 1".).

I've fixed this stupid mistake and i now have a very good flow of about 3000l/h.

I'll let you know how it goes and post some pics soon.

cheers,

Andy.

 

[koiguy1969]

it had to help...are you saying that its after the skippy or there is no skippy just the pot setup? if there is no skippy yet, finish it and put it inline before your pot waterfall. what do you have for a filter other than your pot if the skippys not up and running yet.

 

[Austrian Fish]

The current setup is :

pump ---- filter (UV + a bit of lava rock) ----- pot waterfall (ceramic pots)

The trouble is the filter is a lower rating (2500l/h) than the pump (4500l/h), so i've had to restrict the pump for the moment. But i want to change the filter when i have the cash so it can handle the full flow.

All of this is temporary at the moment. I'm going to add the waterfall and wetlands over the summer, and the pot waterfall will get removed then.

I just wanted something that would help with the green water problem until the rest of the plans get put into effect.

cheers,

Andy.

 

[koiguy1969]

what container are you using for your skippy filter?

 

[Austrian Fish]

This is something i've still got to work out. The range of suitable containers are not that good here in Austria. Fish keeping and ponds seems to be relatively new to Austria and there aren't any specialist shops... at least i haven't found one yet.

I've got a 5000l pond, and i was planning on using a small water barrel that would sit behind the waterfall..... but i'm not sure how to get a waterfall effect from that barrel. I was going to fill it with a mix of foam and ceramic.

Can you recommend a container?

cheers,

Andy.

 

[koiguy1969]

well the stock tanks are for watering farm live stock, you must have some farms there, so in turn farm supply stores. a 70 gallon like mine would do a fantastic job on your pond. and is easy to build a waterfall around. then you can order the kit from the skippy site its everything you need to build the filter with instructions minus the tank. that includes the proper media.