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Discussion Starter · #1 ·
Hi,

I have got some questions regarding BGA (or Ciano Bacteria).

1) It's typically associated with zero Nitrate. My understanding is that once there's no N in the aquarium - plants and algae starve while BGA that can do nitrogen fixation thrives. True? Simplistic?

2) I read that BGA is the main source for available N in our world because N2 that's in the atmosphere is innert. Why isn't it taking over all the plants in our world? Why was it overtaking my aquarium then?

3) I read that BGA is associated also with DOC - Dissolved Organic Carbon. What's that? How do I increase/reduce this thing?

4) I heard that BGA happens also with NO3 = 70 ppm. Is it the same BGA?

5) Ponds have tons of sun light, dirt, zillions of nitrate sucking plants, high temperatures - why aren't all ponds taken over by BGA?

6) I have the feeling that once it has taken my tank - it's there and if I turn off the UV, no matter what the nitrate level is - It shall take over again. True?

7) Some indicated that it's not only nitrate levels - other macros as well - so how about potassium? Could lack of potassium trigger this nasty thing?

8) It's associated with high temps. because high temps. means higher bacterial growth - yes?

9) What about flow rate? Why low flow rate is causing BGA?

10) Any other triggers for BGA?

Thanks,

Aviel.
 

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BGA needs very little N to begin with, Oscilliatoria does not form conspicous heterocyst, which are used for fixing N2 from the air.

If you have plants, fish, there's enough N for the BGA without any need from the N2 from the air.

While some spcies do fix N2, eg Anabeana in Azolla, the species/genus that infest out tanks does not.

Misinform assumptions about this can cause problems, but generally adding KNO3 and keeping up on plant health solves 99% of all algae related problems and low NO3 vs N2 fixation is not going to make a differences in terms of treatment.

BGA has a high requirement for Fe to fix N2, there is a high energy cost associated with fixing N2 gas vs NO3 or NH4.

It is found in many low nutrient regions of the planet, so you could argue it has taken over those regions, eg central open oceanic gyres, desert soil cryptogramic crust etc.

3) Do a water change, but I do not find BGA in non CO2 tanks to be any issue, so I would argue it does not aplly well to observations(DOC=> tendancy for BGA presence).

Dirty filters, clogged filters seem to correlate though.

4) I had a high light tank with plants etc and 75ppm for 3 weeks, no algae was produced.
But don't try this, nor would I suggest this level, I do stuff like this for fun, you might not find algae blooms fun.

5) Because the plants are better competitiors for light and remove all the NH4 being produced. Every water body has BGA and many species of algae.
At higher nutrients, the plants will establish and become dominant. This takes time, but once the plants do take hold, they are the main producers. Algae are good at fast life cycles and changes, plants need more long term stabilty.

Each has a life cycle, set of requirements/niche, plants and algae are in different niches.

6) Nope. UV only kills what passes through it, it does not deal with any surfaces in your tank. I have BGA in my tank, I cannot see it without a microscope, but it's there waiting.
I have not had a BGA issue for many years.

7) No other macros seem to correlate well except in terms of limiting plant growth.

8) Higher temps can also mean faster plant growth.

Lygbya(A BGA) and Hydrilla have no trouble growing together at 40C.

9) Allows the BGA to speread without mechnical destruction. Plants are tough, BGA filaments are not(at least our species).

10) poor maintenance

To clear it up, water change, KNO3 dosing, and blackout(3days) and then add KNO3 from then on to assure it does not return.

It's one of the easiest and cheapest algae to get rid of.

Antibiotics are often suggested but the blackout is as effective abd solves the long term issue, poor plant growth. Antibiotics have no place in BGA treatments as there are much more suitable treatments available and that are more cost effective and as fast if not faster.

Regards,
Tom Barr
 

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Discussion Starter · #4 ·
response

Tom,

I asked

3) I read that BGA is associated also with DOC - Dissolved Organic Carbon. What's that? How do I increase/reduce this thing?
U answered

Do a water change, but I do not find BGA in non CO2 tanks to be any issue, so I would argue it does not aplly well to observations(DOC=> tendancy for BGA presence).
I do not understand the answer - the english sentence that is. What is DOC? It should be something that is dissolved in the water - but what is it? To reduce yes water changes - I understand. But what increases this thing? What's the conenction to CO2 or non CO2 tanks?

Another question that I asked

What about flow rate? Why low flow rate is causing BGA?
I didn't understand

Allows the BGA to speread without mechnical destruction. Plants are tough, BGA filaments are not(at least our species).
Do you mean if I have good flow then it won't be able to build because the "wind" shall always destruct whatever it's trying to build? But you know Tom that there's always dead areas where BGA could build. No?

Regarding blackout - people lost plants during blackouts. Esp. sensitive plants - I took one plant and stored it dry for 3 days. Then I took another one and put it in a water container for 3 days. The dry one survived. But the wet one did not.

Aviel.

Aviel.
 

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for what its worth... my speculation is that BGA is symptomatic of excess bacterial activity. Vacuming mulm, rinsing filter media, and cleaning the glass when combined with a waterchange seems to help. If you really want to wipe it out, follow-up the cleaning with a course of antibiotics and anouther waterchange. I still don't understand Tom's recomendation of blackout for BGA because in my tool box that's a greenwater tool. Perhaps there's more than one way to skin a cat?

Reduced bacterial populations will increase available N and stimulate plant growth. If you have healthy plants and get them growing well, after reducing your bacterial load, they will repress the nitrifying bacterial population by using ammonium as it is produced.
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Jeff

mor b, I think azolla is a symbiotic host plant for BGA
 

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My experience with BGA indicates that it is linked with a deterioration of water quality which may result from accumulation of dead fauna, dead flora, and/or accumulation of muck under dense low level plants.

A focus on improving water quality can easily clear BGA up:

- aeration at night
- small water changes on a 2 or 3 times a week basis
- pruning all affected plants
- rubbing off and vacuuming off rocks and wood
- reviewing dosing of fertilizers to re-establish correct levels as the tank recovers

I have found Seachem's Flourish Excel kills off BGA effectively. Excel, for whatever reason harms BGA (without harming other fauna and flora).

A black out is not necessary and might even compound problems. The good thing about BGA is that it is not hard to get rid off and does not require a complete tear down.

Andrew Cribb
 

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Jeff, a 3 day blackout is 100% effective, yes 100% against killing BGA.

Aviel,
#1 was answered=> 50% weekly water changes.
#2 DOC=> dissolve organic carbon, basically carbon based stuff that build ups and presist in the water and is slow to be broken down by bacterial actions.
3# Non CO2 tanks do not get water changes at all, months on end, but they do not possess BGA either but have a build up of DOC levels.
#4 BGA needs to have a low flow area to establish, other wise it will get blown away and not be able to grow.
When your filter gets clogged, this can occur and the decrease in flow and increase in rotting material in the filter can cause more O2 to be used up and lower circulation can cause plants not to grow as well.

DOC may correlate to some degree with BGA in some tanks, but this does not imply causation.

#5 A 3 day blackout and you lost(or anyone) plants? Those plants were dead and gone before you did the blackout.
Wholesalers could not ship plants if this was an issue.
Common sense will tell you that.

Yes, even sensitive plants.
Not sure what type of container etc you put it in, but I can send any plant in 3 days and have it arrive just fine if it's not too hot or too cold.

If your plants cannot survive a 3 day blackout, you should toss them.

In the tank is another story also, if the plants cannot handle being in a poor environment that you created to begin with, it's not due to a lack of light if it's 1.5-2w/gal or higher. It's due to a lack of NO3 etc. So not adding light for 3 days should not cause an issue.

If you want healthy plants, add the nutrients and CO2.
That's why you have the algae in the first place.......

Telling people to do a blackout to control algae is extremely sound advice and something I've done for some time with many folks and a 100% success rate thus far all over the world.

Simple, cheap/free, effective, addresses long term cause.

Regards,
Tom Barr
 

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Discussion Starter · #8 ·
Tom,

One more BGA question - this time regarding red field ratio. I remember I read an article about N:p that should be 16:1... beyond that and you may have green algae, below that and you may have BGA. The dutch guys even provided a calculator - you need to replace this amount of water and add this amount of KNO3 in order to be safe...

I would like to know whether this thing is true. While I can logically understand your call for ample po4, kno3, light, co2 - I fail to understand how the ratio matters. Maybe it's becaue if po4 is high the rate at which the no3 is diminishing could bottoms it without the hobbyst being aware? Is that it?

Aviel.

BTW - regarding my previous questions - I know DOC stands for dissolved organic carbon. But what causes this thing in our tanks? dead leaves? Excess food? Excess CO2? Dead fish?
 

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BGA, when it is taking over the tank, is avoided by snails, but I have seen that a blackout makes it edible after about four or five days, and the snails start eating it. I think that in the dark, the BGA can't make its toxic and/or bad tasting defensive compounds, and after a while, it looses the defensive compounds it had made earlier, and it becomes good for snails to eat. However, you may have to keep the lights off for a long time if you wait for the snails to finish eating a large amount of BGA. It is better to clean out all the BGA you can before the blackout so that the snails can finish up the remnants fairly quickly.

I have also seen that a good dose of nitrate can cause spreading BGA to clump up into tight clumps, and the snails then also seem to like it better.
 

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Regarding herbivory, Paul's notion may very well be true.

Aviel:
I've held ratios do not matter unless drastic imbalances occur, or that the levels become limiting which is often the case in natural systems.

If you have a non limiting condition, I see not reason why a 10:1 vs 20:1 ratio with N:p would make any difference in terms of plant growth.

The effects in natural systems are very subtle and difficult to tease apart, often times, all an alga needs is slight edge to keep it's life cycle going and in the evolutionary playing field.

This is very true in the Oceanic systems with algae. Few plants live in open oceans and in general, waves, depth, herbivores are much more of an issue. Redfield's ratio is for marine phytoplankton, not FW plants.

Plant ratio averages are 10:1.

Ratios can help maximize your KNO3, KH2PO4 usage I suppose, but when the stuff cost 23$ for 50lbs, I'm not worried about adding a little more for insurance. Better to have more than I need than too little.

DOC builds up if you do not do water changes s a fraction of decomposition of plant, food, dead stuff etc.

It reaches a critical level and bacteria really start working it over and breaking it down.

Tannins levels reach only so high in many areas for this reason rather than building and building.

The bacteria(decomposers, not BGA) may help influence BGA if you use higher light/CO2, but I doubt it. I have non CO2 tanks that never get water changes and I have not BGA in there.

Does the CO2 help BGA?

Not sure, but generally yes, CO2 helps algae also.

Regards,
Tom Barr
 
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