# Nitrates and blue-green algae



## Lissette (Apr 2, 2005)

I don't mean to hijack your thread, but rather than start a new one regarding the same subject, which is BGA, I'd rather post here and answer a few of your questions as well to the best of my knowledge.

You can get KNO3 from Greg Watson. He sells KNO3 for cheap, as well as other nutrient supplements that your plants will need. Shipping is very fast, and he has great customer service. Here's a link to his website:
http://www.gregwatson.com/

NO3 is Nitrate and K stands for Potassium. PO4 is phosphate. All three are macro nutrients required for your plants.

Dosing depends on a few factors: a) size of your tank, b) amount of light that you have, c) co2, d) plant mass, e) fish load, and f) water changes.

There's really no way of knowing how much to dose in your tank. Tweaking with it is the only way to find out. Deficiencies can also be noticed when your bottoming out of some nutrient. In other words, you have to watch your plants closely to find a balance.

Maracyn may get rid of the BGA for a while, but like anything else, there's no guarantee it won't come back in a few weeks. If it doesn't, great. But don't be too surprised when you see it in your tank again. It's worked well for some people, but other people have not had that luck, myself included. Even blackouts are sometimes ineffective. I've tried it 4 times already and it still comes back. And yes, I've covered my tank well, and added No3.

I used a test kit to measure for No3. The kit has always shown 10 ppm. But I noticed that a few of my plants were showing signs of deficiencies, and on top of that, BGA.

I've added more No3 than normal and checked the plants for any sings of improvement since last week's b/o. A week later, there's a big improvement in plant health. Every plant in my tank has been pearling and growing like weeds. There are no deficiencies, a few green spots on the glass, but not on the plant leaves.

What does that tell me about my test kit? That it can't be trusted.

However, even after dosing more No3, I still have BGA. According to a dosing calculator on another forum ("Fertilator"), which by the way, is an excellent calculator (at least in my opinion), I dosed 55 mls of Nitro +, which gave me more than 22 ppm of No3. 

So why do I still have BGA? Will it go away if I keep dosing 20 ppm of No3? Should I dose more?

I guess I'll find out in a few weeks' time, and if it's still around, then No3 can't be causing the BGA, because the tank has more than enough of this nutrient. I have a very light fish load, and my tap has 0 No3.

Sorry this post is so long, but for those that are just starting out, this thread can help them better understand No3 and what really causes Blue Green Algae.

Lissette


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## bgssamson (Mar 16, 2004)

jaybird002 -

The dip stick test kit is not accurate (IMO) buy the Master liquid test kit Aquarium Pharm. it is far more reliable than the ones you have. If you think it is expensive, those liquid test kit will last for a long time than your stick. I see you live in Arlington, VA. I live in Alexandria so the water params. shoulnd't be way diferent (I think!). Get your Nitrate to 10-20 ppm (IMO) & make sure you have enough water current from your filter.

Note:
Please post all the info. needed:
Tank size, light wattage, dosing (fertilizer), fish/es, ammonia, nitrite, nitrate, ph, kh, gh, etc....
========================

Lissette,

What size filter do you have in your tank? check if you have enough water current for your tank, that might be the culprit.

Note:
When adding nitrate check your fish for any weird behavior like gasping for air it is letal if you put too much.



-Brian roud:


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## Lissette (Apr 2, 2005)

Brian,

I use the AC HOB (30-50gal). I also use A/Pharm. test kit for No3. 

I'm aware that adding more No3 will harm my fish, but so far, they're doing okay. I'm afraid to add more.

Maybe your right, maybe I don't have enough current in my tank. But what can I do to remedy this problem? It's only a 29 gal. tank.

Lissette


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## m.lemay (Jul 28, 2002)

I did not see any mention of co2 or how mnay watts per gallon on your tank???


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## Wasserpest (Jun 12, 2003)

Lissette said:


> Maybe your right, maybe I don't have enough current in my tank. But what can I do to remedy this problem? It's only a 29 gal. tank.


Adding a little powerhead would be a good way to increase current.

You can knock them out with EM and with the higher nitrate levels they might not come back. Or, like me, you do it the patient person way, keep up nitrates, wait a few months, and one day they start to disappear.

I think stirring up the places where they are, and increasing water changes could help as well.

Nasty, stinky stuff, that BGA... :icon_roll


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## shalu (Jan 16, 2003)

higher NO3 will not kill existing BGA. You can do a blackout, it should not come back if NO3 is good. When I got BGA, I did use EM instead of blackout.


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## jaybird002 (Apr 29, 2005)

OK, here is my tank information and water perimeters, although you say the dip stick tests are not accurate.

29-gallon tank, 40 watts regular fluorescent light. Plain gravel substrate, with Flourish tabs and couple spoonfuls of laterite around the sword plant. Other plants: 2 anubias nana, some floating water sprite, hornwort (most removed after becoming algae clogged), and a bananna plant. Plants grow, but algae grows better. I had upgraded to a 55w compact flourescent. It helped the swordplant grow taller leaves, but it helped the algae grow more, so went back to 40w regular flourescent.

Ammonia-0. Nitrite-0, Nitrate -20 (barely?), pH- 7.8 or 8 (that's the local water; I'm not messing with it.), GH-150, KH-80. Whisper 40 power filter. No C02 injection. No dosing of liquid fertilizers.

Fish: 4 neons, 2 glolight tetras, 2 cory cats, 3 otocats, 2 Siamese algae eaters, 1 betta, 1 angelfish.

Another interesting fact. Beard and brush algae was the main problem until I got the SAE. They took care of that, but then hair algae took over. After removing it with a toothbrush for I month, I had it at bay. Then the blue-green algae took over. I've heard of more extreme infestations, but it's enough to be annoying.

So if anyone has any idea what's going on and how to curb the algae, please let me know.


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## Iggy (Jan 10, 2005)

shalu said:


> higher NO3 will not kill existing BGA. You can do a blackout, it should not come back if NO3 is good. When I got BGA, I did use EM instead of blackout.


 I think Shalu is right there. 

You have to make sure you kill the BGA completely, with either EM or a blackout first. If there is even a trace of BGA left, there is a good chance it will start to thrive again, even if you add KNO3 afterwards.


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## shalu (Jan 16, 2003)

jaybird002, so all your NO3 reading was from fish food, since you dose no KNO3. Well, I had experience with that in my tank. I had very heavy load with many discus, feed them like crazy. So my NO3 test reading was naturally sky high, >40ppm, and I did not dose any KNO3, used K2SO4 instead. But heck, I got a case of BGA! In addition, some plants do show signs of NO3 deficiency. I came to the conclusion, after some discussion with Tom Barr, that I have too much organic nitrate(fish waste) in the water, which needs time to be broken down by bacteria and THEN can be used by plants. So now I do more water changes to keep organic waste lower and dose KNO3. BGA has not come back for quite some time and plants are healthier.


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## Troy McClure (Feb 22, 2004)

Anybody try hydrogen peroxide on BGA?


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## m.lemay (Jul 28, 2002)

I'm beginning to think that organic waste really is the major culprit for most algae outbreaks. As these organics break down or rot they release tiny immeasurable amounts of NH4(ammonia). These amounts are usually immeasurable because they're quickly used up by the algae and plants.

Best bet is to make sure the substrate and canisters stay fresh and clean.

Marcel


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## plantbrain (Dec 15, 2003)

It works.

Do a good cleaning and filter cleanign etc, prune plants back, vac 1/4-1/2 the tank's gravel each week for 2-4 weeks if not done for a over a year etc.

Basically clean the gravel if the other issues check out.

I have a 100% treatment record with every test I've done using KNO3 and blackout.

Regards, 
Tom Barr


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## Lissette (Apr 2, 2005)

Hello everyone.

Wasserpest,

What size powerhead should I use?

I have tried the b/o method before. Just finished one last Tuesday. I've tried E.M. in the past, but then green water took over for the 1st time. That was a delightful experience. But I'd rather have g/w than that awful smelling BGA.

________________________________

The bga in the tank is very weak. The smell is not as pungent as it was before the 3 day b/o, and it appears in some spots on the glass. Maybe it's dying? I did a w/c yesterday and I dosed 55 mls of No3 again to see if it goes away. I'm hoping something will work.

I appreciate everyone's opinion.

Lissette


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## plantbrain (Dec 15, 2003)

If it's a mild infestation, namely a bit on the gravel, you can vac it up and use a plastic paint scaper to get below the gravel line.

Do that and keep things clean and well dosed, especially KNO3 and CO2 and things should clear up fine.

Many folks have that6 occur but with good consistent dosing and KNO3, we seldom ever see it.

Regards, 
Tom Barr


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## Lissette (Apr 2, 2005)

Thanks Tom. 

I'll keep everything clean, continue dosing enough No3, and I'll continue to monitor the Co2.

Lissette :wink:


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## Troy McClure (Feb 22, 2004)

Since we're talking BGA - will Maracyn II work the same as Maracyn? I have some of the II in the stand for my 29gal and was wondering if that will get rid of the BGA in my 10gal. I've upped the NO3 and put H2O2 on some patches with decent results, but I want to kill it.


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## plantbrain (Dec 15, 2003)

So cover the tank so that 0% light gets in for 3 days, why bother with the other stuff?

Regards, 
Tom Barr


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## Iggy (Jan 10, 2005)

Troy McClure said:


> will Maracyn II work the same as Maracyn?


 No unfortunately not. 

Maracyn II is for gram-negative bacteria. Maracyn is for gram-positive. Cyanobacteria falls into the gram positive category.


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## Lissette (Apr 2, 2005)

Well, I have to admit it. Tom Barr was right. The BGA is finally gone. I no longer see it on the glass, and the plants are doing very well.

I guess a higher dosage of No3 was all that my plants needed. At least it worked for me. 

Thanks Tom.

Lissette


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