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fwpy
Koi Lover

Oct 7, 2002, 6:46 PM

Post #1 of 63 (69562 views)
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Hi,

My name is fred wong and I am new to this forum. For the past week I have been following some of the posting and discussions in this forum and found members very helpful, encouraging and informative. I am facing a serious ‘green water’ problem and am rather desperate for a solution to combat this horrible scourge.

I have an outdoor concrete pond measuring about 10’ x 6’ x 2.5’ with a capacity of approximately 935 gallon (4,250 liter). The pond is served by an above ground 3-chambers filtration system. A submersible pump placed in a sump chamber connected to the pond feeds the filtration system. Another pump provide aeration to the pond. The first chamber consist of mainly corals of various sizes, second chamber with rough filter matt placed vertically and third chamber fitted with fine filter matt placed vertically followed by filter sponge placed horizontally. For 6 years this system has worked wonderfully. The water was clear and pH within normal level. The pond is well shaded with palms and an outdoor umbrella. I clean the filtration chambers regularly, each time partially washing the corals (in bags) and filter matt. The heavy wastes and dirty water was drained off. Each time about 20% of the pond water was replaced.

This work out fine all these years until some 3 months back when the pond water started turning green. I observed the water greening process for a week. At the end of the first week I decided to clean the filtration chambers and replace about 35% of the pond water. For 3 days the water appears okay, then started turning green and by the end of the 2nd week it was completely green again. I follow-up with chemical treatment thereafter with no avail. In the last 6 weeks, I have tested almost every available chemical and water conditioners in the market with negative results. The water is so horribly green now that I could hardly see the fishes in the pond. Apparently this green water has not affected the fishes yet. I met up with some enthusiast at a koi farm last weekend and was advised to replace my corals completely and start a fresh biological process of breeding a new batch of microorganisms all over again. I have bought new corals, fireballs and some new filter matt and intend to replace the coral and 50% of the water next weekend. I am also thinking of UV light sterilization and putting some water plants.

I need your advice and I hope forum members will be able to help me find a solution to this green water problem.

Thanks n Best Regards
fwpy

dttk
Senior Member

Oct 7, 2002, 8:07 PM

Post #2 of 63 (69516 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hi Fred

, welcome to the forum. The green water problem gets worst when you clean the biofilter and make water change outs. UV clarifier is the fastest way to clear the problem. If you don't want to use it, I suggest you give some time for the bacteria which produces a certain phytoplankton-killing enzyme to grow so that the water will become clear again. This bacteria grows best if 1)you have a pump which could give a pondwater turnover rate of once per hour thru the biofilter. 2)you have sufficient oxygenation and biomedia to support it's growth. 3)you have a thick layer of algae on the walls of the pond. The bacteria loves to feed on this algae and releases the enzyme into the water as it is doing so. Other supportive measures would be to reduce nitrate levels with plants. Since your pond is sufficiently shaded, there shouldn't be any problem with sunlight. Changing too much water and cleaning too much of your biofilter will kill alot of these bacteria resulting in more phytoplankton and green water. So, instead of changing more water, just wait and try to achieve the above mentioned conditions for the good bacteria to grow. By the way, the green water is not bad for the koi if you make sure that ammonia and nitrite are not detectable and nitrates at a reasonable level like below 50ppm. Pls do not hesitate to ask more if you need further clarification. Happy koi keeping! Smile

Always friendly :)

(This post was edited by dttk on Oct 7, 2002, 8:09 PM)

fwpy
Koi Lover

Oct 7, 2002, 11:00 PM

Post #3 of 63 (69499 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Tks dttk.

I appreciate your good advice and will follow your suggestions to build up the living organisms in the biofilter.

I will find a pump of the right capacity to give the pond water a turnover rate as you suggested. Now, what about the aeration pump which do not feed the biofilter? Do I need to stop this pump temporarily?
To support the growth of bacteria, I am currently using ‘BIOZYME’ applying about 150ml per day for a week.
Unfortunately, the pond walls are bare of algae altogether due to heavy dosage of algaecide in the last few weeks. I have stop applying algaecide for more than a week now. However, there are heavy built up of string algae from the filtration chambers to the waterfalls area but no sign of algae in the pond walls and floor area.

The water pH at the moment is still within normal range and nitrate level quite balance.

Lynne USA
Koi Lover

Oct 8, 2002, 6:24 AM

Post #4 of 63 (69489 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hi Fred Welcome,

My guess is that over a period of 6 years your koi have really grown allot, this results in more feeding and more waste to feed the algae.

I've given up trying to get rid of my green water Sly

the koi love it and I can see their lips when they eat. Sly

Pretty soon the weather will be cold and the algae will vanish in my pond and I will be able to see them again.

Right now I have 2 clear ponds with new filters that are still cycling and 2 that are green.

I didn't haven't had much luck with my UV's helping rid the pond of algea.

dttk
Senior Member

Oct 8, 2002, 10:28 AM

Post #5 of 63 (69480 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Fred

, 1)keep the aeration pump going. This would provide more oxygen to the water which is good for the bacteria. Do you have air supply(Hiblow) to your biofilter? This would help the good bacteria grow faster. 2)Yes, algaecide does more harm by removing the algae on the floor and walls of the pond which acts as food for the bacteria. 3)adding biozyme may not be helpful as this group of bacteria is not easily grown. Better to ensure that the 3 earlier conditions I mentioned in my previous post are fullfilled. 4) string algae cannot be removed by UV light. I'm afraid you'll have to manually remove them from the waterfall area and mechanical filter if they grow out of control. I have string algae in my waterfall and waterway too eventhough the water is crystal clear. My koi loves them as food. Don't despair, have patience and you'll be rewarded later. Cheers! Smile

Always friendly :)

johnson lee
Koi Kichi

Oct 8, 2002, 10:30 AM

Post #6 of 63 (69480 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hello Fred

Warm welcome to the Forum! Cool

Your pond sounds so much like mine. The dimensions are almost similar (except mine is around 4-5' deep). I too have a pump-fed filter system to 5 filter chambers above ground.

I do not have any bottom drains. Didn't know about this until I found this forum! Crazy

Dr Tan has advised you appropriately regarding the causes of green water and regular water change will not allow the algae and phytoplankton to establish. Of course the algaecide made things worse.

If your water parameters are good then you can withhold water changes until the water clears. What is your nitrate reading? Above 50ppm? You might also want to consider installing a TT filter. It works wonders with nitrites/nitrates and the side effect is also clearer water.

How many fishes have you got in your pond? Do you think your present filter is able to cope with ever growing kois?

I would also suggest you replace the corals in the 1 st chamber with black brushes. Brushes is a more effective mechanical filter and also easier to clean. You can put oyster shells or cockles in the last chamber for pH buffering purposes rather than as a mech. filter.

Just my opinion. Good luck an hope your green water clears soon. Smile

Johnson

fwpy
Koi Lover

Oct 8, 2002, 5:03 PM

Post #7 of 63 (69460 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hi everyone,

Thanks for the sound advice.

Yes, I have 36 kois in the pond and they have definitely grown over the years. Their sizes range from 12” to 22”. Johnson has brought up a good point that my present filter may not be able to cope with the growing kois. I will definitely look into expanding or improving my present filtration system. Following Dr. Tan advice, I am feeling much more comfortable now even though I hate the sight of the green water every morning. I have also follow-up with an air supply system to the biofilter. A water reading taken today indicates pH is within level of 6.5 to 7.5 but nitrate has gone to an unusually high level of about 80ppm. What are the best remedies for a lower nitrate level? Meantime, I am withholding any water and filter change until the water clears. What is a suitable substitute for biozyme to help speed up bacteria growth in the biofilter?
fred

cwnchong
Member

Oct 8, 2002, 5:05 PM

Post #8 of 63 (69458 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hi Fred,

Welcome to the forum. You are in good hands, Dr. Tan, Lynne & Johnson has given you their expert advices regarding your green water problem.

Dr. Tan, Lynne, Johnson,

Regarding to Fred's filter media replacement question, can the new filter media be put together with the existing media in the filter chambers to kick-start the new media before discarding the existing less effective media to aviod the new pond syndrome. Or there are other better methods to do this?

(This post was edited by cwnchong on Oct 8, 2002, 5:09 PM)

dttk
Senior Member

Oct 8, 2002, 8:14 PM

Post #9 of 63 (69448 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Fred

, the best way in your case to lower nitrates is by reducing feeding, removing as much dead algae and debris as possible and start introducing some water plants with established root systems into the pond away from the koi. If not, place them in the filter and leave the cover open. Sterilise the plants and roots with dilute solution of Patassium Permanganate(by a quick soak and rinse) before placing them into the pond. Building a TT filter is another option but it takes as long as 2-3 months to kick in. The best thing to do to speed up bacterial growth in biofilter is to add new biomedia. This will answer Chong's question about introducing suitable new media into existing filters before removing the unsuitable old ones. Smile

. Johnson's earlier suggestion of removing coral from the first chamber is good as coral traps dirt easily and not easy to clean properly leading to skin problems for koi later. However, it would not be wise to do too much now since you don't want to further disturb the filter and cause further reduction in good bacteria. This is best done after the green water clears and the corals can be removed, cleaned thoroughly before reintroducing into the last chamber. If your biofilter still have some space, put in some new mattings and increase oxygenation. Increase your flow rate thru filter and hopefully things will improve. Continue monitoring nitrates and pH. I would prefer to keep the pH between 7.4 to 7.8. Low ph slows down bacterial growth. Best way to increase pH now is by adding baking soda (sodium bicarbonate) at a rate of abt 50g per ton. This will bring the pH up slowly. Do this weekly until your pH is between 7.4 to 7.8. Do let us know of your progress. Smile

Always friendly :)

fwpy
Koi Lover

Oct 8, 2002, 10:19 PM

Post #10 of 63 (69439 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hi everyone,

Thanks for all the encouragement you have given me. I am now confident my green water will clear in due course.

Concerning new biomedia, the middle chamber of the filter tank still has some space and I will put some new matting into this chamber to help the growth of new bacteria.

By the way, how about removing one third of the coral in the first chamber and putting in its place new black brushes? In this way, I can gradually transfer all the coral from the first chamber to the last chamber.

I also have a spare fiberglass filter tank with 3 chambers, measuring 38” x 12” x 20”. Is it advisable to use this filter tank solely for water plants or should I add on as a new biomedia? Is pandan plant suitable for this purpose? I ask this question because I saw in one hotel where pandan plant was grown in the pond. Alternatively, I am also thinking of converting this fiberglass tank into a TT filter. It can be done with some modifications.

Fred

dttk
Senior Member

Oct 9, 2002, 10:19 AM

Post #11 of 63 (69423 views)
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Fred, yes, it's a good idea to add some new mats to the biofilter. I guess there is no harm if you transfer the coral gradually from last to first chamber. Yes, good idea to make use of your spare FG tank as veg filter to remove nitrates. So divert some water from pump into the FG tank. Smile

Always friendly :)

Lynne USA
Koi Lover

Oct 10, 2002, 12:37 AM

Post #12 of 63 (69393 views)
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Re: [dttk] green water problem [In reply to]	Can't Post

When I put new matting into a filter, I always use one of the old ones to help get the cycle started. In my pond it seems to cut the filter cycle time in half. It will mature in 3 weeks instead of 6. Just my humble opinion. Lynne

dttk
Senior Member

Oct 10, 2002, 10:33 AM

Post #13 of 63 (69383 views)
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Re: [Lynne USA] green water problem [In reply to]	Can't Post

Yes, I believe it does speed up the colonisation process. Wink

Always friendly :)

johnson lee
Koi Kichi

Oct 10, 2002, 1:05 PM

Post #14 of 63 (69375 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Hi Fred

Sorry for the delay in replying. Been outstation for a couple of days!

Anyway, you are in good hands so long as Dr Tan is around! Smile

Lynne too has provided you sound advice. Isn't this a great forum?

As the good doctor has mentioned, you can gradually transfer all the corals to the last chamber and why not, if you have a spare filter, use it as your vege filter!

I would advise replacing the corals with oyster shells or cockles in the long run. Yes, replace the corals and change to black brushes. This is a better mech. filter.

Your pH of below 7 doesn't sound too good. Immediately increase the pH with baking soda (sodium bicarbonate as suggested by Dr Tan).

Best wishes to you.

Johnson

fwpy
Koi Lover

Oct 10, 2002, 9:22 PM

Post #15 of 63 (69355 views)
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Re: [johnson lee] green water problem [In reply to]	Can't Post

Hi everyone,

You guys are great. I am beginning to understand the working of a proper filtration system now.

I noticed some algae growth on the walls of the pond today. Can’t see the floor area, as water is too green at the moment. I started pH improvement with baking soda. The pH reading is about 7 today but nitrate level had increased to about 100ppm.
I will gradually transfer the coral out off the first chamber and blend it with cockleshells in the last chamber to start a new cycle.

I was toying with the spare FG tank the past 2 days. Based on Mark Richman and Khoobg’s postings in this forum (High Nitrate level – Try this, posted on 22 May) I got some idea of the working of a TT filter. Mark’s drawing of his TT system is an excellent guide. I did some modification to the FG tank and got it going today as a vege filter.
The first chamber is filled with filter mat laid vertically. Water plants (water lettuce) are placed in the 2nd, 3rd and last chambers. Water is feed through a ¾” pvc inlet to the first chamber. The outlet is a 2” pvc connected to T-shape pvc drilled with little holes (idea from Mark’s drawing). Water trickle down to an earthen jar of 2’ in height filled with bio-balls. These bio-balls sit on top of a plastic grating placed 6” above the floor. At the bottom of the jar is a 2” outlet that allows water to flow back to the pond. I have also cracked a few holes on the jar to allow more air supply to the bio-balls. Hopefully, this dual purpose of a vege and TT filter works. I am giving the system a two weeks trial and will report on the results.

The water readings taken this evening after the system was put into operations – pH about 7 and nitrate level about 100ppm. Please give your comments.
I will try to post a drawing of this system later. The trouble is that I am a hopeless artist and can’t even draw a strait line.

dttk
Senior Member

Oct 12, 2002, 10:19 AM

Post #16 of 63 (69330 views)
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Re: [fwpy] green water problem [In reply to]	Can't Post

Fred, a nitrate level of 100ppm is a little worrying eventhough koi are able to tolerate a nitrate level of upto 200ppm. Your pH of 7 is so-so as long as it doesn't drop below 7 at certain times of the day. Do continue to add baking soda gradually until pH is 7.4-7.8. I suggest you reduce feeding immediately. Start introducing those long rooted water plants as mentioned earlier and remove the remaining coral from the first chamber and remove any debris there without making too much water change. This should bring your nitrate down to a more comfortable level for the koi. Smile

Always friendly :)

fwpy
Koi Lover

Oct 13, 2002, 8:01 PM

Post #17 of 63 (69309 views)
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Re: [dttk] green water problem [In reply to]	Can't Post

Hi Dr. Tan,
I have removed the remaining corals from the first chamber and replaced them with brushes, laid vertically. The second chamber is now filled with filter matts(old n new) and the last chamber has a combination of filter matts(old media) and cockle shells(new) & corals.
In addition, a second vege filter was introduced today. 2 vege filters running now.
Hv controlled feeding since 10 Oct.
The water readings for sat & sun remained unchange, pH about 7 and nitrate level above 100ppm. The fishes appeared okay except 2 which was observed popping out quite often in the last 2 days.
Wink

dttk
Senior Member

Oct 14, 2002, 9:36 AM

Post #18 of 63 (69295 views)
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Fred

, glad to know that most of the necessary steps to reduce nitrate have been implemented. You won't see a sudden drop in nitrate. Instead there will be a steady drop if you continue the above measures. As long as the koi are not too uncomfortable, it is ok to wait till is nitrate lowered. Don't worry abt reducing feeds because the phytoplankton itself is a source of food for the koi. Have you increased the flowrate thru your biofilter and added some air tubings to it? The pH of 7 is abit on the lower side. I suggest you increase it to 7.4-7.8 by adding baking soda. This would definitely help the biofilter to mature faster. Let's just wait and continue monitoring the water parameters. Smile

Always friendly :)

fwpy
Koi Lover

Oct 15, 2002, 9:21 PM

Post #19 of 63 (69271 views)
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Dr. Tan,
Yes, I have increased the flow rate since last week. Put in a new pump with a flow rate of 12oo gph which is sufficient to maintain the pond turnover rate of one cycle in an hour. Have also installed 2 air supply lines to the 2nd n 3rd chambers and seem to be working fine.
There was a slight improvement in the water readings taken this evening, pH about 7.5 and nitrate level about 95ppm. Heavy rainfalls in the last 2 days and water appeared to lightened slightly. At least could see fishes swimming in the pond now. Wink

dttk
Senior Member

Oct 16, 2002, 9:48 AM

Post #20 of 63 (69260 views)
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Fred

, I'm happy that things are turning out fine for you. You've taken all the right steps. Wink

Continue with minimal feeding and monitor nitrate regularly. You should see further reduction in it's level as time goes by. pH at 7.5 is great. Rain water is actually slightly acidic and too much of it actually messes up the biofilter Unsure

. But it's the rainy season. So just top up with baking soda whenever it drops to below 7.0 Smile

. Do continue to update us and hope to see some pictures of your koi and pond when water clears up. Wink

Always friendly :)

andyng
Koi Lover

Oct 16, 2002, 12:26 PM

Post #21 of 63 (69251 views)
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Hey Doc,

Need to get more info on rain water, you mention that it is slightly acidic???.

I was thinking of channeling water from my roof into the pond. I have a section of the roof which collection water from 2 section and a lot of water drops down on to the floor next to the pond. I believe if it rain for about an hour it would fill up one quater the pond. Is that a good idea.

Andy Ng.

dttk
Senior Member

Oct 16, 2002, 1:27 PM

Post #22 of 63 (69248 views)
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Andy

, not a good idea to use run-offs from the roof or gutter as the water is very polluted and not safe for koi. Eventhough there's plenty of rain nowadays and we may try to save water, use it for other purposes other than adding to your pond! Smile

Always friendly :)

SMW1
Koi Kichi

Oct 16, 2002, 4:46 PM

Post #23 of 63 (69236 views)
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Not only does the rain water have a lower PH than any koi pond, if you channel it from any unclean surface like your roof or gutting it can also introiduce a whole host of parasites and toxins into your pond.

I would reccomend that this is never done by anyone who cares about their koi. It's far too risky.

Stuart

johnson lee
Koi Kichi

Oct 17, 2002, 1:47 PM

Post #24 of 63 (69214 views)
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I agree with Dr Tan and Stuart regarding the no no of using rain water. I recall someone on this forum who had his pond located near the edge of the roof and every time it rains, it messes up his pH and causes problems to his kois.

Better be safe than sorry.

Johnson

fwpy
Koi Lover

Oct 22, 2002, 12:19 AM

Post #25 of 63 (69157 views)
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Re: [johnson lee] green water problem [In reply to]	Can't Post

Hi Sifus,

Just to keep all of you posted of development this end. Not much improvement so far becos the filter is not ready to rock yet. Water still very green n water para remained unchanged over the past few days, pH abt 7.5, nitrate level abt 95ppm n ammonia abt 0.2. I am continueing with min feeding n maintaining pH at this level with baking soda. Nitrate level not dropping. The kois seem to be in good condition n the water plants in the vege filter are thriving.

Over the weekend, the remaining corals in the first chamber was removed n replaced with brushes. This chamber now function as a mech filter. I've also installed a temp pvc pipe to divert some water from the waterfall to the pond via a clay pot filled with cockle n sea shells. Hope this experiment will help to stabilisied the pH.
I observed a few fish flashing. Is is alright at this stage to do some salting to the pond? Pls advice.

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