Dosing nitrates (KNO3) to combat cyano

[syncro]

Thanks for the replies everyone.

Are you assuming they are elevated because you have cyano? First thing to do would be test phosphates.

Months ago when the problem started I tested at 0 phosphates. Yes I believe cyano is consuming all phosphates.

As for the Redfield ratio, are you trying to reduce phosphates or remove the cyano?

Remove cyano.

... start out trying ChemiClean.
Cyano? Chemiclean FTW!! :-)
+1 Chemiclean

Thanks for the suggestion. How does ChemiClean prevent cyano from returning? I am worried it is a temporary fix.

Right now your cyano might be using up the Nitrates more efficiently then other stuff in your tank.

Possibly! Is there anyway we can easily test this hypothesis against mine below?

My hypothesis is the DSB is starving the macro algae of nitrates and feeding the cyano with nitrogen. It is common for DSBs to reduce nitrates. I believe they work by hosting de-nitrifying bacteria which consume nitrates. A by-product of de-nitrification is nitrogen gas (my sand bed releases bubbles). Cyano is unique in that it can utilize atmospheric nitrogen. This could explain why the cyano grows well and prefers the sand bed while macro algae won't grow.

adding more nitrogen could bloom the cyano even more

Yes. I think it is critical to remove all cyano first (possibly using ChemiClean here). Then setting up an environment for macro algae to outcompete cyano - by dosing nitrates

[Reef Pilot]

Originally Posted by syncro

Yes. I think it is critical to remove all cyano first (possibly using ChemiClean here). Then setting up an environment for macro algae to outcompete cyano - by dosing nitrates

Actually, dosing carbon or using bio pellets will feed the cyano. You are correct, though, to first remove the cyano with ChemiClean. It works very well, if you follow directions. Then dose MB7 which provides beneficial bacteria to your tank, which out competes cyano.
http://brightwellaquatics.com/produc...robacter7t.php
It is not necessary to turn off your skimmer with MB7. Works great.

I would never intentionally add nitrates to a tank, given all my effort over the years to get rid of it.

[syncro]

Originally Posted by Reef Pilot

Then dose MB7 which provides beneficial bacteria to your tank, which out competes cyano.

Thanks Reef Pilot. I did try two weeks of full dose MB7. Cyano grew back even faster while dosing. Do you think I need to dose longer? The bottle is over a year old (though stored in the fridge and no expiry date listed) so maybe it isn't active now. The problem with MB7 is we don't know what bacteria is in it - what does the bacteria need to grow (carbon? nitrates? hamburgers?)

I would never intentionally add nitrates to a tank, given all my effort over the years to get rid of it.

I understand. My tank has had 0 nitrates since the cycle ended. I think because of the DSB.

[Reef Pilot]

Originally Posted by syncro

Thanks Reef Pilot. I did try two weeks of full dose MB7. Cyano grew back even faster while dosing. Do you think I need to dose longer? The bottle is over a year old (though stored in the fridge and no expiry date listed) so maybe it isn't active now. The problem with MB7 is we don't know what bacteria is in it - what does the bacteria need to grow (carbon? nitrates? hamburgers?)

Two weeks and stopping won't do anything for you. You have to keep dosing MB7, heavy for a couple weeks, and then tapering off, as per directions. I dose 1 cap every 3 or 4 days for a 100g tank on a permanent basis.

But to initially get rid of the cyano, you need to use ChemiClean. After that, the beneficial bacteria from your MB7 dosing should be taking hold. Of course other parameters need to be good as well, like P04 and KH (higher is better). And you need lots of flow in your tank. If there is any detritus in your tank, use a toothbrush to clean your rocks, and a turkey baster.

[Jakegr]

Proven method: Turn off your lights for 3 days, or only light the tank with blue light for 4-5 days (cyanobacteria do not absorb in the blue part of the spectrum). This is not long enough to harm corals, but the cyano will die off.

Reducing tank temperature to <74 F will also kill off most of it. I just noticed this in the last few months, when I gradually reduced my Q-tank from 80 to 73.5 F since the live stock were going to be transferred to a seahorse tank.

I highly doubt dosing nitrates will improve the situation. Nitrates are utilized by all algae, and the ones that grow the fastest will use it first... I would be afraid it could cause a hair algae bloom, or make the cyano worse.

[syncro]

Originally Posted by Jakegr

Proven method: Turn off your lights for 3 days

Won't it grow back when the lights come back on? I tried this treatment on a flatworm problem. It worked but only temporarily.

Reducing tank temperature to <74 F will also kill off most of it.

Great finding! I do run the tank at 77F. This might be a long term solution.

I would be afraid it could cause a hair algae bloom, or make the cyano worse.

Me too!

[Jakegr]

Originally Posted by syncro

Won't it grow back when the lights come back on? I tried this treatment on a flatworm problem. It worked but only temporarily.


Great finding! I do run the tank at 77F. This might be a long term solution.


Me too!

The lights-off technique works best if it is combined with manual removal of cyano, some sort of nutrient control such as GFO and reduced feeding, and, if possible, increasing flow. You are right though, it will come back if the under lying cause isn't taken care of.

I'm actually really enjoying running my tank at 73.5 F. Evapouration is greatly reduced (my 85 gallon system evapourates ~3 gals/week) and there are a few other benefits such as increased O2, lack of cyano, reduced feeding requirements, electric savings and fewer potential pathogens in the water (important for sea horses). It would most likely reduce SPS growth however.

Anyways, good luck!

[syncro]

Some links on this topic:

http://wateralchemy.blogspot.ie/2012...arbon.html?m=1

Simple solution, add more nitrate! AND possibly more organic carbon. obviously if your nitrate limited you need to add nitrate to remove your leftover phosphate levels, but, if the level of phosphate is too high, then just like to remove phosphate you have to add more nitrate because you are nitrate limited, you may have to add more organic carbon simultaneously as by increasing the ratio of nitrate to phosphate, you may have also decreased the ratio of organic carbon to nitrate, and therefore may have (to a certain extent) become organic carbon limited again.

http://www.nano-reef.com/topic/30589...en-on-purpose/

I've been nitrate dosing for a few weeks now, no gfo, 0.3mg/l nitrate, daily.
Cyano started all over within 3-4 days, it lasted just over a week and receded rather quickly.
No3 now reading less than 0.02, Po4 0.01. Still feeding 3x daily heavy.

[paddyob]

Originally Posted by Jakegr

Proven method: Turn off your lights for 3 days, or only light the tank with blue light for 4-5 days (cyanobacteria do not absorb in the blue part of the spectrum). This is not long enough to harm corals, but the cyano will die off.

Prove by who? Could you post the link to the scientific study?

It definitely did not work for me. I ran only Blue+ for over a week and it had zero effect.

Unless by blue you mean Actinic, which has little value to any tank, and which most people are no longer using as better lights have replaced them.

Sorry, but this did not work for me. Cyano is a bitch.



I say Manually remove daily. Chemi clean is a bandaid you may have to redose again.

Try Chemipure Elite.

It is great. Give it a read. It takes about 6 weeks but the product lasts for about 6 months in your tank before replacing.

[Jakegr]

Originally Posted by paddyob

Prove by who? Could you post the link to the scientific study?

It definitely did not work for me. I ran only Blue+ for over a week and it had zero effect.

Unless by blue you mean Actinic, which has little value to any tank, and which most people are no longer using as better lights have replaced them.

Sorry, but this did not work for me. Cyano is a bitch.



I say Manually remove daily. Chemi clean is a bandaid you may have to redose again.

Try Chemipure Elite.

It is great. Give it a read. It takes about 6 weeks but the product lasts for about 6 months in your tank before replacing.

By blue light I do not mean "blue+" bulbs. Aquablue+ is a bulb type with an unfortunate name. It is a broad spectrum bulb that emits quite a bit of light above 500 nm, which cyanobacteria absorb readily. "Actinic" is not a scientific term either.

When I say blue light, I mean light in the 400 - 475 nm part of the spectrum.

Blue light, especially 450 - 475 nm, is immensely valuable to the vast majority photosynthetic organisms. It not only contributes to photosynthesis more than most other wavelengths (other than red), but it is needed for various other physiological functions, such as DNA transcription and blooming in terrestrial plants. Cyanbacteria, however, lack the pigments necessary to absorb light in the blue part of the spectrum.

As far as cyanobacteria not absorbing blue light, I can provide you with dozens. I'm doing a Ph.D. on phytoplankton at UBC and I have mini-library on my computer. Here are a few good reads on the subject. Wang et al., 2007 directly shows cyanobacteria does not grow under blue light.

Carvalho et al., 2011. Appl Microbiol Biotechnol. 89: 1275 - 1288
Das et al., 2010. Bioresource tech. 102: 3883 - 3887.
Wang et al., 2007. Biochem eng. 37: 21 - 25.