# Homing In On Cyanobacteria (aka 'BGA')



## jaypeecee (1 Jan 2022)

Hi Everyone,

As some of you may know, I took an interest in Cyanobacteria some time ago*. Specifically, how do we keep this Blue-Green Menace under control? Preferably, eliminated. I'm finally homing in on a possible answer. There are, in fact, a few options but some are more workable/practical than others. Within the next few days, I'll finalize what I think is the best option and explain further. There is one important caveat that I'll draw to everyone's attention. And that is that I am not an expert in this field, merely a hobbyist who had grown weary of seeing Cyano in any of my tanks.

* please see Cyanobacteria Identification - At Last!

To be continued...

JPC


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## MichaelJ (1 Jan 2022)

Will be interesting...


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## jaypeecee (1 Jan 2022)

MichaelJ said:


> Will be interesting...


...hopefully! 

JPC


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## jaypeecee (17 Jan 2022)

Hi Folks,

I figured that it was (once again) time to add to this thread, which I see as a 'Work In Progress'. I ask that anyone interested views it in this light.

Over the last few months, I have carried out a few experiments to see if it's possible to keep Cyanobacteria (aka BGA) under control, nay, eliminated. Coupled with this, I have read a good many scientific papers to improve my understanding of the factors that promote Cyano. To date, I have identified the following as being important (in no particular order):

[1] Water pH

[2] Water hardness

[3] Phosphate

[4] Iron (and Oxidative Stress)

[5] Total Organic Carbon/Dissolved Organic Matter

I still think it's possible to prevent and eliminate Cyano from our tanks. Indeed, I have done just that in one of my tanks. I'll provide a link.

*To be continued...

JPC *


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## Sprayman60 (17 Jan 2022)

jaypeecee said:


> Hi Folks,
> 
> I figured that it was high time for me to add to this thread, which I'm hoping to approach as a 'Work In Progress'. I ask that anyone interested views it in this light.
> 
> ...


I have had this bacteria and started adding iron and flourish excel too. I added an air diffuser because the circulation was slow and this cleared 80% of it over night


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## jaypeecee (17 Jan 2022)

Sprayman60 said:


> I have had this bacteria and started adding iron and flourish excel too. I added an air diffuser because the circulation was slow and this cleared 80% of it over night


Hi @Sprayman60 

Iron addition would likely have the effect of promoting Cyano. But, _Flourish Excel_ is probably what helped to eliminate the Cyano. _Flourish Excel_ is marketed as 'Liquid Carbon' but is generally out of favour with many UKAPS members if used for its intended purpose.

JPC


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## sparkyweasel (17 Jan 2022)

jaypeecee said:


> To be continued...


Watching with bated breath.


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## Stella (5 Feb 2022)

Hi JPC,
Looking forward to hearing your conclusions. I've had 4 previous tanks over the years and never experienced BGA but it has become my nemesis with my latest tank!! For what it's worth I'll add my amateur observations to the mix....would love to hear your thoughts! 
150 lit tank set up Jan 2019 with 100% tap water. Quickly found out it was too hard (21 GH, 15 KH and high pH 8.2 and 25 mg/l NO3), although plants seemed to grow well! Replaced half the water with RO to get 7GH, 6KH, pH 7.4-7.6) before adding livestock. Used 50/50 tap water/RO (non-mineralised) for water changes. Plants initially grew really well but started to get bad BGA problems by the end of the first year. Water test (dipsticks) gave NO3 at 0-10 mg/l, 0 mg/l phosphate, 7-14 GH, 4 KH, pH 6.8-7. Tried more regular water changes and BGA got worse - covering everything, smelling strongly and visibly reforming and growing within hrs of meticulously cleaning the tank! Started using 50/50 mineralised RO mixed with tap water and raised GH to 14, KH to 6-7 and pH to 7.2 - 7.4. BGA much improved but not totally gone. Bought some new bogwood which stained the water brown and algae visibly shrunk and reduced. Sadly, it grew again once the wood aged and staining stopped. 2 yrs after initial set up decided my filter needed an upgrade so replaced with stronger flow model - this helped greatly and I started feeding plants with occasional root tabs and some solubles, added some volcanic rock substrate to the gravel and I thought I had finally cracked it...BGA was minimal and hard to find! Now 3 yrs after set up I am seeing problems again, although this time the BGA is a brown colour and growing more slowly but otherwise the same as before (peels off in sheets). Photo attached. Water is testing as 14GH, 6-10KH, pH 7.4, 5 mg/l N03, 0 mg/lit phosphate. I haven't been as good with water change frequency of late, nor have I used plant feed for a few months as didn't want to feed the BGA but plants look a bit pale. Any thoughts welcomed on next steps!?


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## hypnogogia (5 Feb 2022)

Your nitrates and phosphates are too low.  How do you fertilise?


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## jaypeecee (5 Feb 2022)

Hi @Stella

Welcome to UKAPS!

Please tell us about your aquarium lighting. What are you using? How long is the lighting on for (this is known as the photoperiod)? What is the brightness set to?

JPC


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## Stella (12 Feb 2022)

hypnogogia said:


> Your nitrates and phosphates are too low.  How do you fertilise?


Thanks Hypnogogia...I thought that might be the case, although a while back my nitrates had increased to 40 mg/l (but phosphate was only 0.25 mg/l) as I was late on a water change and the algae was no better. My fertilising has been a bit sporadic. I was using some root tabs and some soluble feed (Potassium nitrate, Magnesium sulphate,  Potassium phosphate) but I ran out of root tabs a couple of months ago and haven't bought more yet. What levels of nitrate and phosphate would you recommend?


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## Stella (14 Feb 2022)

jaypeecee said:


> Hi @Stella
> 
> Welcome to UKAPS!
> 
> ...



Hi JPC,
I have 2 x 25W fluorescent Aquagrow tubes run for 10.5hrs/day. Same ones used for life of tank.


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## hypnogogia (14 Feb 2022)

Stella said:


> What levels of nitrate and phosphate would you recommend?


I think you can comfortably add 30ppm nitrate and 3ppm phosphate per week, as long as you also carry out weekly 50% water changes.


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## jaypeecee (14 Feb 2022)

Hi @Stella 

Thanks for the lighting information. Unfortunately, being fluorescent lights, it isn't easy to adjust brightness. But, I'd be tempted to reduce the photoperiod from 10.5 h/day to 7 h/day. But, this is only one factor in many.

It's difficult to know where to start. May I suggest that you read the following thread from beginning to end? That will give you an idea of the stages that you _may_ need to go through. Then, come back with your comments/questions.









						Do I have BGA?
					

Forgive my newbie ignorance. I’ve been reading about but just confused myself into whether I need to do anything about this or just let it run it’s course. I’m not 100% sure if this is blue-green algae or just some symptoms of a newly developing tank. It appears to be mostly appearing on mosses...



					www.ukaps.org
				




JPC


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## jaypeecee (14 Feb 2022)

Hi @Stella

Please advise which ferts you are currently using and their dosage (how much and how often). Whilst some aquarists choose not to use test kits, I don't fall into that category. So, please let us know which test kits you are using (if any) and let us have current readings. You mentioned test strips previously but these are not reliable.

BTW, are you using CO2 injection?

JPC


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## jaypeecee (5 Jun 2022)

jaypeecee said:


> I still think it's possible to prevent and eliminate Cyano from our tanks. Indeed, I have done just that in one of my tanks. I'll provide a link.



Here's the link:  Is expensive bio media worth it?

JPC


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## jaypeecee (20 Jun 2022)

Post started in error!



Apologies!


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## jaypeecee (18 Jul 2022)

Hi Everyone,

I was recently in discussion with @Happi. We were discussing how the Total Nitrogen : Total Phosphorus ratio could play a part in the growth of Cyanobacteria. I am not questioning for one moment the success of the experiments conducted by @Happi. But I also discovered a paper that states "TP alone was a much better predictor of both total and relative cyanobacterial biomass than TN or the ratio of TN : TP. (Total Nitrogen : Total Phosphorus). For anyone interested, please refer to the following:



			https://www.tandfonline.com/doi/abs/10.1080/00288330.1987.9516238
		


Also, the section entitled 'Carbon and Cyanobacteria' at the bottom of Page 429 is of interest.

JPC


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## jaypeecee (19 Jul 2022)

Hi Folks,

I started this thread on 1 Jan 2022 specifically to act as a central resource where we can bring together our collective knowledge about Cyanobacteria. Waiting in the wings at the moment, I have various bits 'n' pieces that I hope to add soon. If anyone has a specific Cyanobacteria (aka BGA) problem for which immediate help is required, please start a new, separate thread. 

I hope what I'm suggesting is agreeable to everyone.

JPC


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