# Algae question



## curefan (28 Mar 2012)

Hi,
I built my first pond about a yr and a half ago. It turned out well and has a UV filter leading to the top of a small waterfall. There are no fish in the pond and I never intend having any(enough of them in the house!). I have some plants and a stoned beach effect at the front of the pond, where algae gathers every few weeks.
I use a pond vac to get rid of it. 
I only turn on the pump/filter/waterfall when Im there to enjoy it as dont want have extra energy costs. This might be the rason for algae or maybe the fact that there is not much water movement at the front/beach side of pond.

Is there anything I can put in the pond to kill off the algae that wont harm the plants (fish are not a concern). Really im looking for something that will cut down the pond vacuuming (a bit lazy!).

Thanks, Dave


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## ceg4048 (28 Mar 2012)

I've got a great idea; Why not just feed your pond plants? Then, when the plants are healthy your algae will go away. That way you don't have to kill anything.

Cheers,


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## sparkyweasel (28 Mar 2012)

curefan said:
			
		

> There are no fish in the pond and I never intend having any(enough of them in the house!).



"enough fish"???  No, sorry, you've lost me there.


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## curefan (29 Mar 2012)

ceg4048 said:
			
		

> I've got a great idea; Why not just feed your pond plants? Then, when the plants are healthy your algae will go away. That way you don't have to kill anything.
> 
> Cheers,



...well I pretty much have enough plants in the pond (dont want to take it over) yet I still have algae!?


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## dw1305 (29 Mar 2012)

Hi all,
If you have a lot of open areas in the pond you will get a bloom of algae in the spring what-ever happens, it is 100% natural, and all ponds will have it. If your pond has alkaline water you will get filamentous green algae, the infamous "blanket weed" and if you have a lot of nutrients you will get a lot of it.

Have a look here: <http://www.ukaps.org/forum/viewtopic.php?f=25&t=16737&p=180012&hilit=Darrel#p180012>. You might like this thread as well: "_Little Shop of Horrors - How EI frightened the gardener_" <http://www.ukaps.org/forum/viewtopic.php?f=25&t=123>

This is my garden pond, it has filled in a bit since I took this picture (you can see the blanket weed in it), and as the plant mass has grown the spring algae bloom has lessened. The blanket weed has always declined during the summer as the floating plants grew. For the first couple of years I used spare _ Limnobium_ etc. in the summer for shading, but this year I think the natural vegetation will do it for me.






cheers Darrel


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## ceg4048 (29 Mar 2012)

curefan said:
			
		

> ceg4048 said:
> 
> 
> 
> ...


It doesn't matter how many plants you have if they are starving. If you don't want plants to take over then just prune them. Algae is not a function of how many plants you have. It is a function of how much light and nutrition you have.

Cheers,


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## curefan (29 Mar 2012)

....could you use those feed sticks you see in DIY shops for house plants, that you push down into the pot/basket?
Dont really want to use my aquarium Tropica or it might work out a little expensive  :!: 

Cheers.


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## dw1305 (29 Mar 2012)

Hi all,


> could you use those feed sticks you see in DIY shops for house plants, that you push down into the pot/basket? Dont really want to use my aquarium Tropica or it might work out a little expensive


A handful of "Growmore" and a handful of clay, roll togther them into 5 or 6 balls, chuck in the pond. You can let it dry out if you want to target it at baskets etc. and then just push the balls into the baskets. 10kg of Growmore should last a life-time and will cost  ~ £12.

cheers Darrel


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## curefan (29 Mar 2012)

Nice one, thanks Darrel/Ceg.


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## martin-green (29 Mar 2012)

My 2p worth;   

Lets see. You have a pond which has plants but no fish, you have a bio filter and U.V and pump which you switch on when you want to hear the noise of running water, and you have green water because of algae and you want to get rid of the algae? but you want to save money, which is why you only switch the pump on "as and when"

*The Filter and UV*
A filter and UV do several things. The UV causes the algae to floculate (clump together) these "clumps" are now big enough to get caught in the biofilter's sponges.
The bio part is where bacteria breakdown the fish waste (But as you have no fish they wont be that busy, or multiply that much)

*The algae*
Algae is actually a very microscopic plant, it lives on nutrients in the water.

*Oh dear *
In order to be effective a UV has to be on 24 / 7 and its tube changed every season, also the quartz sleeve should be cleaned when the tube is changed to reduce any lime scale build up, since you do neither you have wasted your money on a filter an UV, Also as algae is a plant adding a "plant growth" product will make matters worse, as yes, it may feed the plants you want to grow, but it will also feed the algae you don't want to grow.

 You do have another option though. Take all the plants out, remove the bio filter and UV (keep the pump) Clean it all out, put several up turned flower pots (or similar) in the area, fill the gaps with gravel or 20mm stones refill with water and you have yourself a water feature that you can turn on and off when you like and no (ok hardly any) green water.






(water spout with gravel)


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## ceg4048 (30 Mar 2012)

martin-green said:
			
		

> ...A filter and UV do several things. The UV causes the algae to floculate (clump together) these "clumps" are now big enough to get caught in the biofilter's sponges.


The only algal species that are affected by a UV sterilizer is green water algae. The OP reports algae on rocks which will never be controlled by a UV.



			
				martin-green said:
			
		

> Algae is actually a very microscopic plant, it lives on nutrients in the water.


This is what everyone in the world focuses on and as a result they miss the big picture. If algae is a plant and is microsopic, does it not follow that they only need microsopic amounts of nutrients to survive? On the other hand, if a plant is 1 million times bigger than microspoic algae, does it not also follow that they require 1 million times more nutrients than algae? So wouldn't the plants be better off with higher nutrient loading?

Algae really do not care about the level of nutrients in the water, precisely because they only need microscopic amounts. The same is true for ponds as it is for aquaria. Algal blooms are triggered by light. Every morning someone turns on this really bright light in the sky. This light bulb, altough being 93 million miles away is very bright, even if there is cloud cover. In an aquarium we can control the lighting level, but in a pond we cannot do so very easily. The combination of malnourished plants and bright lights trigger the onset of algal blooms, regardless of the nutrient level in the water. Nutrient levels can be low or high. It really doesn matter for algae but it matters for plants.

I have very little knowledge of ponds but in every pond I've ever had, all I ever did was remove by hand the algae covering rocks while feeding the plants. No UV, no complications, no dismantling of filters, and the algae disappeared, even with part time filtration just as the OP wants to do:
A. Because algae are predatory in nature and attack plants weakend by malnutrition.
B. Because the plants would grow and shade the water to prevent the light from penetrating the water to trigger blooms.

It's a very simple formula. I dump nutrients directly into the water column in direct contradiction to everyones nutrient phobia, and the results are exactly the same as in aquaria, the algae disappears, as detailed in the pond experiment=> viewtopic.php?f=25&t=123

Cheers,


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## dw1305 (30 Mar 2012)

Hi all,
I'll pass on adding nutrients to the water column, I'm aiming to keep my pond mesotrophic, and I want the plants within the pond to have  a coating of periphyton or "biofilm". What I'm aiming for is stability, and by nutrient reduction I should be able to keep intervention to a minimum, until I do a reasonably big prune in 2014 ish. I would expect a very large algal bloom following the prune, until the plant mass builds up, once again removing nutrients and chopping out the sun-light. 


> In order to be effective a UV has to be on 24 / 7 and its tube changed every season, also the quartz sleeve should be cleaned when the tube is changed to reduce any lime scale build up, since you do neither you have wasted your money on a filter an UV, Also as algae is a plant adding a "plant growth" product will make matters worse, as yes, it may feed the plants you want to grow, but it will also feed the algae you don't want to grow.


I really don't get UV, it removes the "green water" algae like _Chlorella _from the water column, but why would you want to do this? they are visible sign that there is an abundance of macro-nutrients. It doesn't address the reasons why you have an abundance of macro-nutrients, and at least the algae are assimilating nitrogen into proteins. 

*UV = more blanket weed and poorer water conditions*, and people do this voluntarily? it must be one of the greatest acts of salesmanship of all time.

cheers Darrel


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## darren636 (30 Mar 2012)

well. Uv does work. My 5 foot deep pond has prolific plant growth, clear water and massive koi and even babies too   all i do is repot the lilies every year. Stick some root tabs in and sit back and enjoy  the  veronica  beccabunga.


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## Iain Sutherland (30 Mar 2012)

darren636 said:
			
		

> well. Uv does work. My 5 foot deep pond has prolific plant growth, clear water and massive koi and even babies too   all i do is repot the lilies every year. Stick some root tabs in and sit back and enjoy  the  veronica  beccabunga.



Do you not think that in your own words the 'prolific plant growth' is more likely to be the cause behind clear water and a heathy pond?  Unless you have removed your uv for any period to see the effect several times then its a long shot to attribute this to a UV filter.


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## ian_m (30 Mar 2012)

I used to have a pond/water feature with UV steriliser. You could tell when the UV tube needed replacing, about every 12-18months as algae appeared and water feature bit got covered in green slime.

I would clean off algae up as much as possible, dose water with anti algae and replace UV tube and most algae would stay away until tube wore out next time. Also watch out, as some anti-algae is incompatible with UV units, so after dosing have to run with no UV and remember to turn back on after say 2 weeks.

Didn't seem to matter what time of year tube "failed" in both summer and winter algae appeared again, obviously a lot slower in winter.


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## Ed Seeley (30 Mar 2012)

Keeping a koi pond algae free by good plant growth is akin to keeping a planted tank algae free while it has a pair of oscars and a shoal of silver dollars in it.  The koi are gross feeders that produce constant, large amounts of ammonia that a large filter needs to deal with as effectively as possible but there will always be small ammonia spikes after each feed.  Add to this that any decent sized koi views plants within the pond as toys to be played with if possible and you have another big problem.  That doesn't mean it's impossible but it is much harder.

Personally my old pond remains algae free for most of the year as it is overfiltered with a very efficient filter and it has a very large area where emergent plants can grow without the koi.  Even then it has a bloom of green water in spring each year.  Most koi ponds (and my new one) do not have the second part so totally removing algae without help is almost impossible, especially if it has a lot of sun.  And shading it totally isn't an answer as koi need some sun to develop the proper pigments.  The best hope, IMO, is to let the algae bloom in spring and tie up the nutrients.  Then, if it doesn't clear on its own, turn on the UV to clear the pond and remove the clumped algae using a very efficient filter then turn the UV off.  If you get another algae bloom repeat this process.  IME this reduces the growth of blanketweed which just grows if you use a UV constantly to kill off free floating algae.


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## dw1305 (31 Mar 2012)

Hi all,
I think Ed's sounds like a workable method and a good compromise. 





> Uv does work. My 5 foot deep pond has prolific plant growth, clear water and massive koi .....&........ You could tell when the UV tube needed replacing, about every 12-18months as algae appeared and water feature bit got covered in green slime


 Point taken, I'm happy that a UV lamp properly set up kills floating algae, and that the dead cells can then be removed by an efficient filter. The problem is that you have _"shot the messenger"_, rather than addressed the problem, that's why I wrote.


> ...... it removes the "green water" algae like Chlorella from the water column,.......they are visible sign that there is an abundance of macro-nutrients. It doesn't address the reasons why you have an abundance of macro-nutrients, and at least the algae are assimilating nitrogen into proteins.


cheers Darrel


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