# Dealing with the green



## DEL 707 (24 May 2010)

We built ourselves a pond a few years back and it's doing pretty well.
However we've had a pretty persistant problem where the pond is a rather nice shade of green.   

I've tried adding products that's meant to help, but I havn't seen any difference, long or short term.
The pond does get alot of sunlight, I'd tried covering it in water hyacinth's and some lillies a friend gave me, but they never seem to do well, always dying off. The fish are always nibbling.

I'm starting to think the problem is down to filtration, as embarrasing as it is, I can't remember the size of the pond at the moment, but I the filter is a Bioforce 1200 and when I bought it, it was just the *right* size for the pond with a heavy load.
 Would attaching another, maybe smaller, filter to the pond help with my problem? Or am I going in the wrong direction?


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## ceg4048 (24 May 2010)

Some radical ideas in the thread; Little Shop of Horrors - How EI frightened the gardener

Cheers,


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## Ed Seeley (24 May 2010)

DEL 707 said:
			
		

> We built ourselves a pond a few years back and it's doing pretty well.
> However we've had a pretty persistant problem where the pond is a rather nice shade of green.
> 
> I've tried adding products that's meant to help, but I havn't seen any difference, long or short term.
> ...



If you want to clear your green pond then use a UV unit.  It will clear in a few days.  However you will then have water that's perfect for growing blanketweed!

If you want to upgrade the filtration then look at a DIY K1 filter - great bio and mechanical filtration and a peice of cake to clean.


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## ghostsword (25 May 2010)

Hi, for blanketweed I know someone that used this item with good results.
http://www.aquatics-warehouse.co.uk/aca ... iller.html


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## dw1305 (25 May 2010)

Hi all,
The green water is because there isn't any zooplankton (Daphnia, Mosquito larvae etc) to eat the phytoplankton (green unicellular algae like _Chlorella_). You can treat the problem (a UV filter), but this still leaves the nitrates in the water and inevitably this will lead to other algae growing. I'd follow Ed's advice and increase the biological filtration. Here is the K1 filter <http://forum.koimag.co.uk/tm.asp?m=131079&mpage=3&key=>, the other even easier approach is plants, as long as their roots are in the water there is no requirement for their leaves and stems to be anywhere near the fish, additionally if emersed they are easier to remove and permanently export your nitrate.

My personal approach would be 2 fold, create a refugium where the fish can't get to and stock it with Daphnia. The best refugium would be a separate basin (ideally filled with Horn-wort _Ceratophyllum_), but you my be able to use a complex shallow habitat with-in the pond itself (a shallow shelf with a "dry-stone wall" too keep the fish out?). Another option is remove the fish (they won't then add nutrients or eat the zooplankton).

I'll assume you want to keep the fish, so if we go back to the idea of a "header" pond (this can be a water butt etc.) and then half fill it with a fairly coarse aggregate (limestone pea gravel or Alfagrog) and plant this with _Phragmites australis_ Reeds, _Typha_ Reed-mace and/or Water-cress (_Nasturtium_), and you have a planted biological filter with a huge filtration potential and a "nitrate" scrubber. Limestone gravel will also provide Ca2+ ions which will precipitate the orthosphosphate ions out of solution.

This sort of thing. <http://www.pond-solutions.co.uk/pjmvegfilter.htm>

cheers Darrel


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## Ed Seeley (25 May 2010)

Darrel's suggestions for using plants or an area for zooplankton are great as long as you aren't highly stocked or have koi.  They produce so much waste and ammonia that they will defeat any attempt to create a balance and will totally overwhelm the ability of plants to take up all the nutrients unless you are very understocked.  The only filter IMHO that will completely deal with the waste from a decently stocked koi pond without going green is a shower filter (A giant high turnover trickle filter arranged in trays) that vents off large amounts of ammonia direct to air taking the load off the filter.  However even they aren't a guarantee as my green growing on pond is testament too!  (I do have 16 fish in the 400gallons though, with a number about 50cms long so I'm very, very overstocked!!!!)


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## dw1305 (26 May 2010)

Hi all,
Definitely right about the trickle filter, 





> is a shower filter (A giant high turnover trickle filter arranged in trays) that vents off large amounts of ammonia direct to air taking the load off the filter.


 but I think you are underestimating the biological filtration potential of a separate basin with _Phragmites_ reeds. The physical separation of the plants and Koi gets around many of the problems of plants and carp, and the _Phragmites_ plants themselves are very efficient at aerating the substrate, reducing oxygen limitation to nitrification process. The other issue is the build up of nitrate when using a microbial biofilter on its own, the _Phragmites_ are very efficient at mopping these up, and show a linear growth response to nitrogen addition, you can't really over-whelm them with nutrients when they are in active growth, the more nutrients there are the more they grow.

A relatively small reed bed deals with all the secondary leachate from the Carymoor (Castle Cary) landfill site we work on, and the National Botanic Garden of Wales deals with all it's sewerage and waste water using them. This is from the NBGW blurb.

"_The Gardenâ€™s Living Machine is a natural wastewater treatment system. It operates under the same principles as those that regulate the natural ecology of forests and diverse water systems.  Living machines are able to break down many harmful pollutants and purify wastewater.  The processes are designed to replicate the cleaning effects of natural ecosystems.

Wastewater from throughout the garden will be pumped up to an equalisation and anaerobic digester (septic tank) covered by a planted biofilter. The settled waste will be regularly desludged and the solids removed to the compost-making operation. In the secondary settlement stage the wastewater travels to two underground closed tanks located close to, but outside the greenhouse.  The effluent is then pumped into a standard green house through a series of four open aerobic tanks planted with floating rafts of aquatic plants ranging from invasive weeds to rare and endangered Welsh species.  This intensifies the wastewater treatment and provides a very diverse ecology.  After passing through a final biofilter it is passed into a reed bed inside the glasshouse from whence it is discharged into an external wetland for final cleansing.  From there it is discharged onto a grassy hillside._"

This is the abstract from:
Joung Yi Shin; Seok Soon Park & Kwang-Guk An (2005) 
"Removal of Nitrogen and Phosphorus Using Dominant Riparian Plants in a Hydroponic Culture System" 
Journal of Environmental Science and Health, Part A, Volume 39: 3  pages 821 - 834 

"_The objective of the study was to evaluate potential nutrient removal capacities from eutrophic stream waters using two riparian plants, Phragmites japonica and Salix gracilistyla. The removal efficiencies, removal rates of nutrients (N, P), and their specific growth rate were estimated as a function of inflow loading rate and hydraulic retention time (HRT) in a hydroponic culture system. ............ It is concluded that the nutrient removal approach using the riparian plants may be used for efficient water quality management in the eutrophic streams with long HRT._ "

cheers Darrel


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## dw1305 (26 May 2010)

Hi all,
Sorry forgot to add this link for a bit of an over-view of construction and operation. 

http://www.fujitaresearch.com/reports/wetlands.html.

cheers Darrel


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## Ed Seeley (26 May 2010)

What are the removal figures Darrel?  Is there any data of how much ammonia they'll remove?  Don't get me wrong I wouldn't have a pond without plants, but I won't rely on them to remove much ammonia/nitrate at the moment!!!


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## dw1305 (27 May 2010)

Hi all,
Ed this is a figure from: 
"Completely autotrophic nitrogen-removal over nitrite in lab-scale constructed wetlands: Evidence from a mass balance study" Suna, G. & Austin, D. (2007)
Chemosphere 68:6, June 2007, pp. 1120-1128.
Abstract
"_Landfill leachate containing low BOD, but a high concentration of ammonia, was treated in four wetland columns under predominately aerobic conditions. Influent total nitrogen in the leachate consisted mainly of ammonia with less than 1% nitrate and nitrite, and negligible organic nitrogen.........Through mass-balance analysis, it was found that CANON (Completely Autotrophic Nitrogen-removal Over Nitrite) was responsible for the transformation of nitrogen into gaseous form, thereby causing the loss of nitrogen  mass. The results show that CANON can be native to aerobic engineered wetland systems treating wastewater that contains high ammonia and low BOD._ 






PM me with an email address and I can send some papers (including this one). Here's the one I was sent this morning. 

"Chemical oxygen demand, nitrogen and phosphorus removal by subsurface wetlands with Phragmites vegetation in different models"
Debing, J., Baoqing, S., Hong, Z &  Hong J. (2010)

Abstract
"_To improve the removal efficiency of subsurface wetlands vegetated mainly by Phragmites, pilot-scale gravel-based wetlands were used to treat sewage characterized by chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) pollution. For Phragmites vegetation, COD, TP and TN removal loads of wetland vegetation with Phragmites australis-Typha angustata-Scirpus validus as main species reached 0.517 g m-2 d-1, 0.277 g P m-2 d-1 and 0.023 g N m-2 d-1. The COD removal loads in pilot-scale and medium-scale (260 m2 in area) wetlands with Phragmites-monoculture vegetation were 0.62-0.64 g m-2 d-1, while that of P. australis-T. angustata-S. validus wetland reached 0.974 g m-2 d-1. Thus, the preferable poly-culture model for Phragmites wetland vegetation was P. australis, T. angustata, S. validus and Zizania latifolia with stem density ratio of 8:1:5:1. After harvest, nitrogen and phosphorus standing stocks of wetland vegetations ranged only 2.2-9.93 g N m-2 and 5.39-13.5 g P m-2, respectively, as both the above ground biomass and the nitrogen and phosphorus contents of the wetland vegetation harvested in late autumn were low_".

cheers Darrel


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## Ed Seeley (28 May 2010)

Cheers Darrel,  Just sent an e-mail.

I think the use of plants and a new kind of filtration called biocenosis baskets could really add to a traditional nitrification pond filter and I intend to have planted baskets alongside traditonal filtration on my new pond.  The main issue with any filter used with koi ponds is still solids removal though as the fish are so messy so I'm going to have two fairly automated methods of solids removal followed by a shower filter.


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## dw1305 (28 May 2010)

Hi all,
Hi Ed, a new name for me, but I understand the principle. I've just had a look at this link <http://www.essexsection.co.uk/html/anoxic_filtration_part_1.html>, and that is very much what I had in mind.

Kevin Novack posts on here: <http://www.koiphen.com/forums/showthread.php?p=1826809>

cheers Darrel


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## Ed Seeley (28 May 2010)

I'm not convinced that they would run a well-stocked koi pond on their own yet, that's why I'll enjoy reading the papers with some hard data.  As I'm going to have planting baskets suspended in the pond though I thought I may as well try the kitty litter and laterite mix and see if I can see any effect!  Can't do any harm!  Still going to rely on a sieve, shower and some air lift drains for the real filtration!


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