Help me understand low phosphates regarding Cyano Bacteria

[Snoopdog]

So I am past the dinoflagellate stage and I thought I had my phosphate problem fixed. The last I tested it was visible on my test kit. After two or so weeks of Cyano that has not gotten worse or better I decided to test again. My nitrates have dropped some and well the phospates are either zero or .01, very low. It got me thinking though, the cyano seems to form on my sand and on the dead rock, not my live rock. I started thinking that possibly the sand and the dead rock are deficient, does this have any merit? Why does the cyano like these places better? I am going to start getting that phosphate dosing going again and maybe it will resolve the cyano issue a little better. I never had this problem with my last tank 12 years ago in fact my phosphates were always readable. If I keep dosing will I finally be able to quit dosing at some point?

 

[Nano sapiens]

True healthy live rock develops an assemblage of various different micro organisms (aka 'Periphyton') that when in balance prevent any one organism from overpopulating and causing a 'bloom'. The sand substrate is a different environment with detritus/organics that can provide just the right conditions for cyanobacteria growth.

As far as phosphate goes, each aquarium has it's own character in regards to usage due to a whole host of factors. The current reefing recommendation is to have at least 'some detectable PO4 present' since many reefers in the past have succeeded in starving their reefs with excessive use of phosphate removal methods and many have experienced dinoflagellate blooms.

A caveat to this story is that some systems run 'undetectable PO4' naturally (like my old established reef aquarium) and the corals grow and color up just fine. In these cases, phosphate is also being supplied as organic phosphate (which we can't test for with our typical home test kits) when the aquarium is fed regularly. Organic phosphates are eventually converted into inorganic phosphates via enzymatic process, so that adds to the complexity of phosphate utilization in our systems.

Good read for phosphates:

https://reefs.com/magazine/chemistry-and-the-aquarium-phosphorus-algae-s-best-friend/

 

[Snoopdog]

True healthy live rock develops an assemblage of various different micro organisms (aka 'Periphyton') that when in balance prevent any one organism from overpopulating and causing a 'bloom'. The sand substrate is a different environment with detritus/organics that can provide just the right conditions for cyanobacteria growth.

As far as phosphate goes, each aquarium has it's own character in regards to usage due to a whole host of factors. The current reefing recommendation is to have at least 'some detectable PO4 present' since many reefers in the past have succeeded in starving their reefs with excessive use of phosphate removal methods and many have experienced dinoflagellate blooms.

A caveat to this story is that some systems run 'undetectable PO4' naturally (like my old established reef aquarium) and the corals grow and color up just fine. In these cases, phosphate is also being supplied as organic phosphate (which we can't test for with our typical home test kits) when the aquarium is fed regularly. Organic phosphates are eventually converted into inorganic phosphates via enzymatic process, so that adds to the complexity of phosphate utilization in our systems.

Good read for phosphates:

https://reefs.com/magazine/chemistry-and-the-aquarium-phosphorus-algae-s-best-friend/

Thanks for the read, digesting it now.

 

[Dan_P]

So I am past the dinoflagellate stage and I thought I had my phosphate problem fixed. The last I tested it was visible on my test kit. After two or so weeks of Cyano that has not gotten worse or better I decided to test again. My nitrates have dropped some and well the phospates are either zero or .01, very low. It got me thinking though, the cyano seems to form on my sand and on the dead rock, not my live rock. I started thinking that possibly the sand and the dead rock are deficient, does this have any merit? Why does the cyano like these places better? I am going to start getting that phosphate dosing going again and maybe it will resolve the cyano issue a little better. I never had this problem with my last tank 12 years ago in fact my phosphates were always readable. If I keep dosing will I finally be able to quit dosing at some point?

All other things being equal, microorganisms will grow densely wherever the food concentration is high. Dinoflagellates, diatoms and cyanobacteria all follow this ”rule”. Food is concentrated by the accumulation of particulate matter. Rough surfaces collect more than smooth surfaces, but even smooth surfaces covered with a bacterial biofilm can be sticky and accumulate particles. Dissolved organic material cannot be concentrated in one spot. Reduce the local food concentration to solve your problem.

@Lasse manages his cyanobacteria growth with phosphate and nitrate additions. The thinking is that raising the concentration of these nutrients encourages microorganism growth and competition for cyanobacteria. The mechanism might actually be the reduction of the locally high concentration of food that made life easy for the cyanobacteria. It takes time though to nudge the bacteria population into one that is unfriendly to cyanobacteria film formation. There will always be cyanobacteria, just not so many in one spot. Ditto for diatoms and dinoflagellates.

The bottled bacteria vendors claim that their bacteria will help reduce detritus/scum/slime that is causing your microorganism problems. It is difficult to determine whether this is baloney or not. Work by @taricha shows that aquarium microorganisms in an established system seem to do the same thing or better than the bottled bacteria. Maybe, bottled bacteria are worthwhile for new systems. The situation might be analogous to development of human infant gut microbiomes. They need a good inoculation from the mother and a wide range of inoculations from foods, pets and dirty fingers in the mouth to create a healthy gut microbiome. Aquaria might need to be similarly inoculated.

In answer to your last question, upon establishment of a healthy aquarium microbiome, nuisance organism growth becomes less of an issue, and dosing and other activities to fight these pests become unnecessary. By the way, sometimes a good “rip cleaning” is necessary to knock down an infestation. @brandon429 has described this approach for smaller systems when nudging techniques like nutrient adjustments fail to stop pest microorganisms.

Good luck!

 

[brandon429]

removed

 

[Snoopdog]

I will never do what other people do by tearing down a tank, cook rocks or whatever they call it. That sounds like starting back to ground zero if you ask me. I do wonder though, since phosphate can be eaten by unwanted algae as soon as it enters the water column showing results of zero, is there a time of day you may get a better reading?

By the way, any well written document I read about reef tanks or water chemistry in general are written by Randy.

 

[brandon429]

you'd assume that without reading any details or seeing the degree of tanks corrected?

ok.

 

[Snoopdog]

you'd assume that without reading any details or seeing the degree of tanks corrected?

ok.

Until I research it, yes. Could there be value in it? Sure there could be. But until I have time to sit down and research it I have to consider it as something people are doing that may or may not work. I did not just buy hundreds of dollars to "cook it". I am not sure why they gave it the name cooking rock but still it sounds like a lot of the life in the rock dies off. If that is truly the case that does not sound healthy for a reef tank. I am trying to avoid a sterile tank.

 

[CoralClasher]

I’ll testify for Brandon’s advice. A full cleaning and new water never killed any of my fish or corals. My tank looks better with every rip clean I do.

 

[CoralClasher]

No recooking needed just rinse and reassembled.

 

[Snoopdog]

I am going to try patience first. Nothing good in a reef tanks seems to happen quickly.

 

[CoralClasher]

I am going to try patience first. Nothing good in a reef tanks seems to happen quickly.

Patience is definitely good. I have a different tank growing macros for fish food and I’ve noticed Cyano when No3 is low. I’ll dose NeoNitro and it usually goes away. But I’ve never had Cyano in my DT so I’m unsure if you need more No3 with fish involved.

 

[Lasse]

@Lasse manages his cyanobacteria growth with phosphate and nitrate additions. The thinking is that raising the concentration of these nutrients encourages microorganism growth and competition for cyanobacteria.

I must have been bad in explaining my thoughts. I do not see it primary as a competition for nutrients in the water.

My theory in short

According to mat building cyanobacteria - they are always present but not always form mats. I think that the critical point is when they decide to build mats or with other words take some of the energy from the photosynthesis and excrete a slime of mostly carbohydrates. My idea is that when they can catch PO4 from the water column - they do that and they have some competition some algae and fungus about available space. They stay put. If the PO4 will be sparse or nonexistent - they need to get PO4 from other sources. On way of doing this is to form a mat that create anaerobic environment between the mat and substrate. In this anaerobic environment bacteria will grow - both Nitrogen fixating bacteria, denitrifikation bacteria and when the NO3 is zero or very low - bacteria that produce hydrogen sulphide will establish themselves. The hydrogen sulphide will break the bounds between different metals and phosphate in the substrate and phosphate will be released to the hungry cyanobacteria. If the area they establish themself content a high amount of organic matter - PO4 will be released from the organic matter too. When the trigger had started the mat forming - it becomes a self playing piano between the mat and the substrate - first when all P has gone - the mat start to decline.

According to nitrate - I not only concentrate me on that because it is a inorganic nitrogen source - there is plenty of other sources of inorganic N and even some organic N (amino acids) that unicellular organism can use both in a autotrophic and an heterotopic way (primary and secondary producers). I´m interested of NO3 because it has another important role in anaerobic bacterial community. As long NO3 exist in the water - it block most of the hydrogen sulphide producers, hence the release of PO4 from metal-PO4 compounds in the substrate.

I do believe that low PO4 can be a trigger for mat forming but also low NO3 can act that way too. Probably there is other triggers too. I also believe that there can be part of the tank there it can microenvironment with low PO4 or NO3 - especially in tanks with low flow or dead spots.

Because I see the mat forming as the Gordian knot - I use three actions when the mats has establish themselves. Disturb the mats as much as possible, have enough high NO3 levels in order to have zero hydrogen sulphide production below the mats and if PO4 is low - have a PO4 concentration between 0.05 to 0.1 mg/L. Good circulation (I love standing waves) in order to not establish favorable microenvironment can help too

I agree that this is only a theory and do not need to be the truth. However - the theory have helped me to stand free from Cyanobacteria mat forming for most of the time and with a treatment schema when things goes downhill. The schema include disturbing of the mats, keep up PO4 to 0.05 - 0.1, rise the NO3 up to at least 5 ppm and sometimes go down in light intensity and slowly rise it back to normal during a couple of weeks. The lowering of the light aim to lower the secret (slime) production (they need photosynthesis for that).

I prefer to work with the biology instead of nuking it.

Sincerely Lasse

 

[Snoopdog]

I use three actions when the mats has establish themselves. Disturb the mats as much as possible, have enough high NO3 levels in order to have zero hydrogen sulphide production below the mats and if PO4 is low - have a PO4 concentration between 0.05 to 0.1 mg/L. Good circulation (I love standing waves) in order to not establish favorable microenvironment can help too

This is where I was kind of going with my treatment of it. I am also trying to get a good competing macro algae established.

I prefer to work with the biology instead of nuking it.

This is also where I stand. IMHO I would rather try to figure out why so that next time I can fix it without going to drastic measures. There is too much life in the majority of this rock to risk killing it, plus I have to live with my GF that has grown attached to every living organism in the tank.

 

[Nano sapiens]

My take is that in a mature system started with a good compliment of reef associated microbes (real live rock.sand, etc.), good flow and good husbandry practices (sand bed/detrital maintenance), cyano mat's should be very rare. In 35+ years of reef keeping, the only time I had to deal with nasty cyano mats was on my old 55g (5 years of virtually no water changes and no sandbed vacuuming). Cyano mats will form easily when coral tissue is killed off, so that's a rather good indication that concentrated organics are a primary driver.

 

[Snoopdog]

My take is that in a mature system started with a good compliment of reef associated microbes (real live rock.sand, etc.),

I agree. But that did not happen in this instance. The guy that I bought the tank from used dead rock. It had gone through a cycle but it all appeared dead to me. I have added 30lbs of KP rock to it now and it is looking much better but the tank has had too much change in few months, it will take time to get to an established stage. We are starting to see the light at the end of the tunnel though. Just this week there was a mass spawning of copepod it seems, the glass is covered. Many new worms and micro fauna everywhere, seeing the start of coralline algae. My refugium is starting to show really good diversity. The cyano has definitely lessened but I really think if I wait this out and work on the phosphates, maybe increase feeding of natural foods then the phosphate / nitrate ratio will get better.

 

[flampton]

They stay put. If the PO4 will be sparse or nonexistent - they need to get PO4 from other sources. On way of doing this is to form a mat that create anaerobic environment between the mat and substrate. In this anaerobic environment bacteria will grow - both Nitrogen fixating bacteria, denitrifikation bacteria and when the NO3 is zero or very low - bacteria that produce hydrogen sulphide will establish themselves. The hydrogen sulphide will break the bounds between different metals and phosphate in the substrate and phosphate will be released to the hungry cyanobacteria. If the area they establish themself content a high amount of organic matter - PO4 will be released from the organic matter too. When the trigger had started the mat forming - it becomes a self playing piano between the mat and the substrate - first when all P has gone - the mat start to decline.

As long NO3 exist in the water - it block most of the hydrogen sulphide producers, hence the release of PO4 from metal-PO4 compounds in the substrate.

Sulfate and Nitrate reducing prokaryotes are both within the anaerobic niche. Not sure I've seen any literature that states that the SRP population are reduced by the denitrifiers. Is this part of your hypothesis? Or is there literature that you saw that discussed this competition?

Oh and have you seen if sulfate ever becomes elevated in tanks with higher nitrates that don't perform water changes? That would help the hypothesis I would think a good deal.

 

[Lasse]

Sulfate and Nitrate reducing prokaryotes are both within the anaerobic niche. Not sure I've seen any literature that states that the SRP population are reduced by the denitrifiers.

Look for literature handling with waste water treatment. It has been known for decades that low concentration of nitrate (2 ppm) will suppress H2S production. Fast googling with "nitrate suppressing h2s production" gives some result (around 900 000) - this as an example There is also a very well done Swedish study around NO3, hydrogen sulphide production, anaerobic sediments, PO4 release and vertical migration of Cyanobacteria during night in order to catch released PO4 from the anaerobic zones (in fresh and brackwater) But only in Swedish.

This aquarium (mine) show the following curve over S. I stop WC early 2017. Did A 70 % WC in early january 2018 - no regular WC since that. My Nitrate levels have been between 2 - 10 ppm during this time. And I have active denitrification zones in the aquarium

Normal seawater S around 900 mg/L

Sincerely Lasse

 

[flampton]

Look for literature handling with waste water treatment. It has been known for decades that low concentration of nitrate (2 ppm) will suppress H2S production. Fast googling with "nitrate suppressing h2s production" gives some result (around 900 000) - this as an example There is also a very well done Swedish study around NO3, hydrogen sulphide production, anaerobic sediments, PO4 release and vertical migration of Cyanobacteria during night in order to catch released PO4 from the anaerobic zones (in fresh and brackwater) But only in Swedish.

This aquarium (mine) show the following curve over S. I stop WC early 2017. Did A 70 % WC in early january 2018 - no regular WC since that. My Nitrate levels have been between 2 - 10 ppm during this time. And I have active denitrification zones in the aquarium

Normal seawater S around 900 mg/L

Sincerely Lasse

This is interesting because if you're suppressing sulfate reduction where does your sulfate go? There must be some reduction going on, but only enough to keep things stable. I like it

Going further in the literature it turns out the dissimilatory nitrate reduction to ammonia organisms utilize the NO3 which creates NO2 which they then use to make NH4 but during the process a small amount of nitrite is released which inhibits the SRPs. This suggests if it is working in the aquarium that there is a decent population of DNRA organisms. I have been wondering that, and if its working a bit in your aquarium then there is definitely DNRAs there. I wonder how much nitrate can be reduced to ammonia daily in the aquarium? That ammonia must go into the heterotrophic biomass or be shared with the AOPs, which would result in a futile cycle for our purposes, haha!

Thanks for sharing this information Lasse!

 

[Lasse]

Surprised that this is not very known because when I heard about it was already in the 80:ties - just before the discussion about nitrate as a growth limiter in sea water was introduced. A large chemical firm had developed a method to be rid of H2S in sewage systems (one of the larger treat to the health for sewage workers) and try to have this method accepted (and sold) to many municipalities. The method was simple - just add NO3 into the sewage. Unlucky for them (at least in Sweden) short afterwards the alarm of NO3 induced eutrophication in seawater came

The first explanation that I heard was the the electron acceptor explanation - oxygen -> nitrate -> sulphur compounds-> carbon dioxide but it shows up that it was mostly other organism than the oxygen - nitrate group that was responsible for the H2S production. There was no super bacteria that could swing between oxygen, nitrate and sulphur compounds as electron acceptor. (however - lately - the discovery of non-sulphur purple photosynthetic bacteria have shown that it exist ) - maybe its time to relearn again

I have to admit that I have not dig in further in the literature recently because this knowledge have been as the law of gravity for me - self-evident I have missed the nitrite explanation - however I have not put this together with only DNRAs and if the nitrite theory is true - it must be valid for both the classic denitrification and maybe even the sulphur driven autotrophic denitrification - both processes know for producing nitrite as intermediate stage. However I have some doubt because I have seen occasions with both nitrite and H2S in the water. But I leave it to you for deeper digging And nitrite is necessary in the anammox process - the process that convert NH3/NH4 directly into N2

However - nitrate in the water suppress H2S production - and it has been my dogma for many years when I have advocated for readable NO3 concentrations in our aquaria > 2 ppm. And that´s the reason why I use NO3 in the fight against cyanobacteria. I know it works but that is because lack of usable nitrogen for other organisms I do not buy - NH3/NH4 use to be common together with cyanobacteria when they use their toolbox of different ways for nitrogen fixation. The explanation for NO3 effectiveness in this situation must be an other and this theory (H2S production suppressor) have been the best fitted for me to now. But I´m no microbiologist - only a very interested hobbyist that have many strings on his lyre ( a translated swedish expression for a multi-tasker)

Sincerely Lasse