# New High Tech Setup - Sudden Algae Outbreak Part 2



## Dr Mike Oxgreen

New member alert!

I set up a new nano tank about a month or so ago, and I'm getting *exactly* the type of algae that the OP has illustrated in his photos: brown, fine, cotton-wool like growth on the wood and some plants. It can be removed fairly easily, but regrows incredibly quickly and seems concentrated in the middle of the tank. Definitely not BBA or anything like that.




 


 

Let me give some details:

*Tank* - 40x25x25cm, 25 litres (but probably only about 18-20 litres of water).

*Filter* - Eheim 150 'classic' 2211 external canister, with water returned through a lily pipe.

*Lighting* - Beamswork 1200 lumen 6500K LED, plus Interpet 2x36cm 'bright white' LED (believed to be 800 lumen, and probably about 6500K). Photo period 10 hours. Difficult to compare wattages between LED and T5, but if we assume that T5 tubes are about 70 lumens per Watt, then I guess my lights are roughly equivalent to about 28 Watts of T5, so perhaps just over 4W per US gallon. Quite a lot, but I'm aiming for high light and I believe nano tanks need more light?

*CO2* - Pressurised, from a Soda Stream cylinder. About 1 bubble per second at the moment, but will probably reduce it slightly when the fish are added. Drop checker is a yellowy-green at the moment, at the other end of the tank from the lily outlet. Solenoid comes on 2 hours before the lights, and goes off at the same time as the lights. There's quite a mist of CO2, and quite a lot of oxygen bubbles as well.

*Water* - A mixture of rainwater and tapwater, to give a GH about 7 degrees and KH about 4-5 degrees. Ammonia fluctuates between zero and about 0.5-1.0 because I'm dosing with a couple of drops of 35% ammonia solution daily to keep my filter fed - obviously this will cease when the fish are added. Nitrite unmeasurable. Nitrate about 20. pH about 6.0-6.5. Temperature 25. I'm currently doing big water changes of about 12 litres every few days to try and combat the algae, but it's not working!

*Substrate* - I've used a fine-grained 'soil' substrate as my only substrate. The product I used specifies that it can/should be used as the only substrate.

*Plants* - HC, Glosso, Crypt wendtii 'brown', Pogostemon erectus, Eliocharis acicularis and parvula, Anubias nana 'mini', couple of sprigs of hornwort from my pond. The HC and Glosso are doing well, bubbling nicely and needing regular trimming, but the crypt isn't doing much (although it also hasn't lost a single leaf). The hair grasses are only just starting to get going, and the poor Anubias is getting a bit enveloped by the algae. The pogo initially melted badly but has stabilised and is now sending down masses of roots from the nodes in the stems.

*Fish* - Currently none, but I have 8 Boraras brigittae, 8 blue cherry shrimp and 3 Otocinclus arriving on Friday. I'm aware that the otos will need feeding with algae wafers, courgette, spinach etc. Actually, I say 'none', but there are some snails, and I spotted a damselfly nymph (probably from the pond hornwort - maybe not my best idea).

*Fertilisation* - TNC Complete, after every big water change.

So, any ideas what the cause of my brown cotton-wool is? I've read elsewhere on UKAPS that ammonia is considered to be a major culprit; am I overdoing the ammonia drops, or should I continue until the fish are added? Should I increase my fert dosage? I've also read that certain types of brown algae may be typical in a new tank (due to silicates?) so will it simply go away eventually? Will the shrimps and/or otos eat it?

Any advice and/or reassurance gratefully received!


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## john dory

I'd reduce the photo period to 6 hours and reduce lighting intensity.
I'd stop adding amnonia and just keep cleaning.


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## GHNelson

Hi Welcome to the ukaps Dr Mike!



Dr Mike Oxgreen said:


> but I'm aiming for high light and I believe nano tanks need more light


Higher light is not necessary for a Nano tank set-up!.....Initially your algae problems are being enhanced by too much light!
Reduce your lighting to 5 hours per day! Use only the Beamswork lighting for now till you get the algae problem rectified.
Purchase some fast growing stem plants to help cycle the aquarium!
Purchase some floating plants....there is a For Sale Section...although you need to make 25 posts to get access!
Ditch the ammonia drops........your filter should be seeded by now after 4 to 6 weeks! 
Remove as much algae as possible manually...a tooth brush or a washing up brush are helpful implements.
Do the largest water changes possible 80% - 90% this will help reduce organic waste.
Have a look at the below set-up with lower lighting from its conception.
http://ukaps.org/forum/threads/my-best-low-tech-scape-so-far.38709/
Cheers
hoggie


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## Dr Mike Oxgreen

Thanks for replying!

As you say, my filter is definitely cycled because the ammonia disappears within six hours or so and I don't see any nitrite at all - but I was under the impression that I needed to keep some biological load on it (hence the ammonia) in order to prevent the bacteria simply dying back. Is that incorrect?

I did have just the Beamswork light for a few weeks, but it looked like the Glosso was 'stretching' a bit so I added the Interpet light over the front of the tank. Both the HC and the Glosso are now growing very pleasingly and the Glosso in particular is staying much flatter, so part of me is reluctant to reduce the intensity - perhaps I'll start by reducing the period and see how it goes.

At the moment I'm using one drop of ammonia twice a day, so I'll reduce that to once a day, unless you're sure that my filter will stay active without it in which case I might eliminate it altogether. It's certainly powerful stuff!

The fish are coming by mail order from Kesgrave Tropicals, who are based in Ipswich but sell through eBay and get good reviews. It's a very small disappointment that they won't be delivering until Friday because I'm keen to get them, especially if it means I can quit the ammonia, but hey - I'll just have to be patient!


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## GHNelson

Hi
If you are worried that your filter will be compromised by removing the ammonia drops...just add a pinch of fish food!
This will be a much safer way of keeping the filter bacteria healthy!
When acclimatising your new arrivals I would be very vigilant as you are adding highly oxygenated/aerated water inhabitants into a Co2 injected tank! 
Cheers
hoggie


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## foxfish

Hi Dr Mike, keep reading the forum post and you will soon discover the importance of C02 & light balance.
High light or perhaps more accurately put .. too much light to match the available C02... is the main cause of algae!
Get the flow & C02 in harmony & then match the light to avoid algae, you do not need high light to get a spectacular display of healthy plants! 
Adding Ammonia!!!!!
You will also discover that using many of the readily available  test kits is generally shunned upon in the planted tank.... I will let you find the post on that one!
A PH pen on the other hand is extremely handy to have around, test you PH before the gas comes on, when the lights come on & when the gas goes off. That information will be very important to you.( & us if you want help)
Please don't rush to get fish in the tank, as soon as you have live stock you run the risk of gassing them with excesses C02.
Without fish you can afford to experiment with Co2 levels, PH drop & lighting.


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## dw1305

Hi all, 
Tank sounds a good set-up, and the filamentous diatoms should start to disappear soon. 

I'd definitely reduce the lighting period, and or intensity, I have all the tanks on a 12 hour light period, but where I have bright lights I use a lot of floating plants.  





Dr Mike Oxgreen said:


> but I was under the impression that I needed to keep some biological load on it (hence the ammonia) in order to prevent the bacteria simply dying back. Is that incorrect?


I think that is probably the problem, pretty much all you read about "the cycle" and "cycling" in aquarium forums is at least partially incorrect. 

Have a look at this thread and links <"Best way to cycle...">.

cheers Darrel


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## Dr Mike Oxgreen

Right, I did another big water change today, but I'll refrain from adding ammonia today. I've added a dose of TNC Complete, and I also tried adding a few drops of barley straw extract. Who knows whether that will help?!

Slightly surprised that the NO3 is reading about 40 now, which is perhaps a touch high.

I've reprogrammed the lighting and CO2 timers to reduce the photo period down to 6 hours as well, still with CO2 coming on 2 hours before. And I've tweaked the CO2 up a fraction, although that might have to come down when my fish arrive. You're right: I'll have to watch the CO2 when the fish go in.


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## Miss Pennyapple

Hi there, I can't help with the algae problem (having one of my own!), but if you want to keep the filter cycled and ready for fish you will need to keep feeding it an ammonia source or the bacteria will die off and you may get ammonia/nitrite issues when you add the fish.

I'm about to order from Kesgrave too! Looking forward to hearing how you get on with your new stock.


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## foxfish

Dr Mike Oxgreen said:


> Slightly surprised that the NO3 is reading about 40 now, which is perhaps a touch high.


http://www.ukaps.org/forum/threads/accuracy-of-test-kits.20009/


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## Jaap

I had the same problem a few weeks ago but now it is dying off and will be completely gone in a couple of weeks.

What I did was the following:
1. Increase light intensity to promote good/healthy plant growth. However, you might already have this so ignore.
2. Aeration during night time.
3. Addition of a few shrimp and a few Ottos. I first added 3 cherry shrimp. After one week I added a few more and now, two weeks later, I have 15 shrimp and 2 Ottos. 

All of the above stopped the filamentous diatoms and now they are dying off. Of course some might say that these steps had nothing to do with it and the algae just did its life-cycle and now its dying off.

Thanks


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## Dr Mike Oxgreen

I'm certainly crossing my fingers that the shrimps and/or otos will eat it - that would be very nice! Beginning to wonder whether I've ordered enough shrimps - 8 of them might be overwhelmed by the task.

My fish are arriving on Friday; meanwhile I'll do big water changes every other day, keep dosing with fertiliser, keep the CO2 up, and I'm only going to dose half a drop of ammonia per day. And the lighting/CO2 period is now reduced to 6 hours. Might buy a cheap toothbrush as well to see if I can remove any of it.

I'm pinning my hopes on in being a temporary "new tank" thing, or that the shrimp/otos will eat it, or that the cessation of ammonia dosing will end it.

Out of interest, has anyone ever tried using barley straw extract in an aquarium? It certainly worked in my pond, although it's by no means an overnight remedy.


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## dw1305

Hi all, 





Dr Mike Oxgreen said:


> and I'm only going to dose half a drop of ammonia per day.





Miss Pennyapple said:


> but if you want to keep the filter cycled and ready for fish you will need to keep feeding it an ammonia source or the bacteria will die off and you may get ammonia/nitrite issues when you add the fish.


You can just stop adding the ammonia, you don't need it.

Fundamentally the factor limiting nitrification is the supply of oxygen. If you supply enough oxygen to the nitrifying organisms they can deal with a large amount of fixed nitrogen (bioload), this is why the metric for pollution is <"biochemical oxygen demand"> (BOD).

Additionally if you have plants they are:

Net contributors of dissolved oxygen.
Primary consumers of ammonia and nitrate.
and provide a much larger area for nitrification within the substrate.
The whole traditional "cycle" idea is based on a series of misunderstandings and half-truths, if you like it is a black and white concept in a _"shades of grey" _world_._ In the last ten years RNA/DNA analysis has discovered a large number of ammonia oxidising organisms that we didn't previously know about, many of them <"Ammonia Oxidising Archaea (AOA)">. Every-one should have access to: <"Aquarium Nitrification Revisited: Thaumarchaeota Are the Dominant Ammonia Oxidizers in Freshwater Aquarium Biofilters">, from the abstract: 





> _ For freshwater aquaria, the proportion of amoA genes from AOA relative to AOB was inversely correlated with ammonium concentration._


 There is a lot of similar research from the waste water treatment.

Even if you look purely at ammonia oxidising bacteria (AOB), they are much more flexible than the traditional view.  This is from the conclusion of
<"Strategies of aerobic ammonia-oxidizing bacteria for coping with nutrient and oxygen fluctuations">.





> From this review it is clear that AOB possess several physiological traits that can be advantageous for their survival under conditions of variable substrate and oxygen supply. Moreover, AOB possess a number of enzymological and molecular mechanisms that allow them to maintain the state of their cells under starvation such that ammonia oxidation can start within minutes and at high rates after substrate or oxygen depletion. Furthermore, within the AOB groups, differences exist in adaptation to and competitiveness under conditions of high or low ammonia or oxygen concentrations


and if you look at the link earlier in the thread to <"Best way to cycle a second filter.."> it has a much fuller discussion of the whole cycling concept.

cheers Darrel


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## Dr Mike Oxgreen

Well, every day's a school day! I assumed it was necessary to maintain biological load, but it seems the bacteria are much more resilient than I gave them credit for. That looks like a proper peer-reviewed paper, which makes it very high-quality evidence. I will quit the ammonia dosing forthwith.

Today the amount of new brown fluff seems slightly less, so perhaps the reduction in light, the reduction in ammonia (henceforth to be reduced to zero), the continued high CO2 rate and the continued large water changes are having an effect. Maybe the few drops of barley straw extract are doing something??

I have found that siphoning with a 12mm tube allows you to suck a lot of the brown fluff straight out, because it's so loosely attached. Siphoning about half an inch above the HC and Glosso pulls a lot of the fluff out. This won't be possible after Friday, though, when my fish and shrimps arrive - I don't want to siphon any shrimps out! I've also tried using a toothbrush, which kinda works, but for my still-establishing HC it's a bit too vigorous. I reckon I might try a small, soft paint brush instead. I'll clean it out well with white spirit first, though, obviously - I'm not daft! 

Over the last three or four days I have seen small amounts of BGA (Cyanobacteria) on the HC. At the moment it's very limited and isn't threatening to spread very far, so I'm not going to panic. Strangely it only seems to be growing on the small amount of HC that's slightly shaded - perhaps the vigour of the rest of the HC (which is pearling strongly) is keeping the BGA at bay. Not sure what's causing it - from what I've read it can be caused by low nitrate (but NO3 is still measuring about 40), or poor circulation (but I can see CO2 mist swirling over the HC). Does it feed on Phosphate?

On Thursday, in preparation for the fish, I will have to reduce the CO2 which is currently at a very generous 1-bubble-per-second and giving a yellowy-green colour. Will need to be much more conservative.


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## foxfish

So that is one up for us on the Ammonia ..... just the test kits now


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## Dr Mike Oxgreen

Not sure I understand what you mean.

"One up for us" - do you consider this to be some kind of competition?

On the subject of ammonia, you said nothing useful in your earlier reply; you just said "adding ammonia" with lots of exclamation marks. By contrast, Darrel gave high-quality evidence that it isn't necessary to keep dosing ammonia to maintain a filter once it has cycled.

On the subject of test kits, it's no surprise that hobby kits are not as accurate as lab methods. But they're all we have. You can't tell the ammonia, nitrite or nitrate level merely by looking at a tank.


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## john dory

If the algae comes out easily with the syphon...carry on.
Livestock will move away.


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## foxfish

Dr Mike Oxgreen said:


> Not sure I understand what you mean.
> 
> "One up for us" - do you consider this to be some kind of competition?
> 
> On the subject of ammonia, you said nothing useful in your earlier reply; you just said "adding ammonia" with lots of exclamation cycled.


I would not like you to consider me as sarcastic or condescending, I tried (& it seems failed) to make a light hearted response to your post, complete with silmly icon. 
No, not a competitsion, although there are some competitive aspects relating to planted tanks, I am not competitive in anyway!
Re my first post, sorry you feel that way too as I thought it contained some good basic info especially  regarding the PH pen.

Anyway good luck with you tank.


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## dw1305

Hi all, 





Dr Mike Oxgreen said:


> "One up for us" - do you consider this to be some kind of competition?


 I think the problem with most <"ammonia & cycling" and "test kits"> threads (principally on other forums) is that  people tend to have very entrenched positions, and they can rapidly degenerate into slanging matches.

I also think that experienced fish keepers, who keep bare tanks etc., often under-estimate just how skilled and observant they are, meaning that they do the important things without really thinking about them. I still need all the help I can get, and my suspicion is that the stabilisers will never come off my bike. 

cheers Darrel


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## Tim Harrison

I think foxfish was just echoing the general consensus amongst most members of this community that fishless cycling with ammonia is unnecessary, and test kits are often too heavily relied upon. A well planted tank is an entirely different entity to a typical "fish" tank.
I also think that sometimes it's easy to misinterpret good intentions on internet forums in general, its so difficult to communicate effectively without being misunderstood at some stage


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## Dr Mike Oxgreen

I view test kits as just one part of the overall picture. And I maintain that it is not possible to know whether your new tank is ready for fish unless you know that your ammonia and nitrite are zero and that you have the necessary bacteria that will maintain the zero levels, and you simply can't tell that by looking at the tank. For extra confidence it is good to dose with ammonia and watch that ammonia disappear within a few hours. Then you know you're ready for the biological load of fish. I'm not going to introduce fish to my tank unless I'm as certain as I can be that the tank can support them.

Sure, once your tank is up and running with a population of fish, then it becomes much less necessary to test - perhaps even unnecessary. I would agree with that. But I'm not at that stage with this tank, yet.


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## Dr Mike Oxgreen

I am puzzled why this site has such an anti test kit mentality. Just because hobby test kits aren't perfect doesn't mean that they can't provide you with a rough indication of what you're measuring.

For example, if your nitrite test gives you a reading of 2 mg/l, that means that your nitrites are almost certainly not zero, and almost certainly not 5 mg/l either. Most likely the truth is somewhere between 1 and 3 mg/l or thereabouts. That in itself is useful information when you're waiting for a tank to cycle.

So long as you bear in mind the limitations of hobby kits, the information they give you can contribute to your understanding of what's going on in a developing tank. They can also tell you about a trend, even if the absolute value is subject to some inaccuracy.


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## Nelson

I use them when cycling a tank to get a rough indication of how it's going,but don't bother after.


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## dw1305

Hi all, 





Dr Mike Oxgreen said:


> I am puzzled why this site has such an anti test kit mentality. Just because hobby test kits aren't perfect doesn't mean that they can't provide you with a rough indication of what you're measuring.


 I don't think we are anti-testing, and I have tested the tank water in the past via a whole range of analytical techniques.

I'm very interested in the measurement of water quality and If there was a dip meter, or simple reagent test, that summarised the important tank parameters across the whole range of water conditions found in freshwater tanks, I'd advice people to use it. I use a conductivity meter, conductivity isn't the reading you would really want, but it was the only meter that I could find that fulfilled the criteria of giving quick, accurate and  repeatable results over a range of water conditions. You could also say that using a pH electrode, or drop checker (with 4dKH solution and a narrow range pH indicator (bromothymol blue)) to estimate dissolved CO2 levels, is a form of test kit.

*Back-ground to the Duckweed Index*
It was actually while I was struggling to find simple techniques that would give repeatable and accurate values for tank water parameters that it occurred to me that I was coming at it from the wrong direction, and that you could use the health and growth of your plants to give you a visual indication of nutrient status. It wasn't a great conceptual leap, because we already used similar techniques in the lab. via a "_Lemna_ bioassay" (Mkandire et al. 2014 "The _Lemna_ Bioassay: Contemporary Issues as the Most Standardized Plant Bioassay for Aquatic Ecotoxicology" _Critical Reviews in Environmental Science and Technology_ *44*:2) , and I knew from our work with landfill leachate and COD/BOD tests that you could use the combination of trickle filters (for gas exchange) and aquatic plants with access to aerial gas levels to drastically reduce pollution.

This technique is widely used via <"Vertical Flow Constructed Wetlands">. It is the combination of plants and microbes that make these systems so effective. As well as their contribution to nutrient removal the plants create a physico-chemical environment  which vastly increases the diversity and size of the microbial community (we know this from DNA/RNA analysis). Established plant/microbe systems are more effective at nitrification than "microbe only" systems, partially because they have higher levels of dissolved oxygen (although this may reduce the anaerobic denitrification, and out-gassing of NO3). 





Dr Mike Oxgreen said:


> And I maintain that it is not possible to know whether your new tank is ready for fish unless you know that your ammonia and nitrite are zero...and that you have the necessary bacteria that will maintain the zero levels, and you simply can't tell that by looking at the tank. For extra confidence it is good to dose with ammonia and watch that ammonia disappear within a few hours. Then you know you're ready for the biological load of fish.


This is the real issue, it is possible to get reasonably accurate measurement ammonia/ammonium (NH3/NH4+) with colorimetric tests, or an ion selective electrode, but even then there are some difficulties. Because of these problems in relatively non-polluted water scientists still use BOD and biotic indices to estimate pollution, mainly because they are a  more sensitive tool than analytical tests.

We don't actually need to test if we know we have a stable and resilient system with the capacity to retain high quality water when challenged with a large bioload. Heavily planted systems, with a large gas exchange surface area, give us both capacity and resilience.

If we add ammonia it will be removed more quickly in a plant/microbe system than it would be in a microbe only system, but we know in both situations that the nitrifying organisms (usually AOA in aquariums) are much more diverse and flexible than we originally envisioned. This is an <"article by Dr Stephan Tanner"> which looks at microbial filtration, and particularly the "Hamburg Matten Filter",  which combines the properties of both substrate and biological filter.  

*Laboratories*
I'm actually in a position where I could get moderately accurate results for a lot of parameters, mainly because I have access to a  teaching lab. with hundreds of thousands of pounds worth of analytical equipment in it, all the necessary reagents, and the staff who know how to use the kit. Water companies continually monitor their tap water (because they are legally obliged to) but they have dedicated labs. costing millions of pounds to equip and run. Some parameters (metal ions) are easy to measure (via atomic absorption spectrophotometry), but others (NO3- etc) remain more difficult, even with analytical quality equipment. As a general rule dissolved gases (like Cl2, CO2, O2 and NH3) are also problematic, and  pH has problems of interpretation.





Dr Mike Oxgreen said:


> I'm not going to introduce fish to my tank unless I'm as certain as I can be that the tank can support them.


 I think we would all agree with that, it is certainly where I'm coming from.

cheers Darrel


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## Dr Mike Oxgreen

Quick update:

The brown cotton wool is no longer threatening to take over the tank. In fact it may have largely stopped growing. I am gradually brushing it out of the plants using a small paint brush and sucking it out during water changes. The otocinclus have done a fantastic job of cleaning the leaves of the cryptocoryne and Anubias, although less so on the hair grass, HC and Glosso. I guess their mouths are more suited to cleaning larger, flatter surfaces.

I have now increased the photo period from 6 to 7 hours, and will monitor how that goes.

Now my problem is disappearing and/or dying blue cherry shrimps. No idea what's going on there!


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## Dr Mike Oxgreen

I've been thinking back over the timing of when my brown cotton wool outbreak happened, and there might be something interesting. Or maybe not.

(By the way, I'm betting I'm going to be flamed for what I'm about to reveal!)

When I first set up the tank and put the substrate in and the piece of wood, I started cycling the tank using a source of ammonia that I have used successfully in the past. It's free and natural, although if you read online forums there is a lot of totally irrational hysteria about it. Yep: just a tablespoon or so of urine every few days. It works. There is no rational reason not to use it for fishless cycling.

But it works differently from pure ammonia, which tends to give an instant and transient 'hit' of ammonia. By contrast, urine tends to give a much more sustained dose of ammonia that lasts for days - perhaps because I believe it contains no ammonia _per se_ but you've got to wait for the urea to be broken down into ammonia. This is fine, but once you get to the point where the tank is producing nitrite and nitrate and you suspect the cycle is nearing completion it's useful to verify that by checking that the ammonia will disappear quickly, and this doesn't happen with urine because of the continual breakdown of urea into ammonia - even with a fully cycled tank it takes several days for the ammonia to drop to zero if you've dosed with urine.

For this reason, I switched to using a pure 35% ammonia solution and dosing just a drop or two. From this I was able to check that the ammonia disappeared within a few hours so I could be confident I had an efficient bacterial colony and the tank was ready for fish.

And it was a few days after I started using the pure ammonia that the algae problem started. For the several weeks during which I'd been dosing urine, I had been amazed at the total lack of any kind of algae, but as soon as I used pure ammonia the algae pounced. I understand why ammonia causes algae, but why didn't the urine have that effect? Both gave me ammonia of about 1-2 mg/l.

Perhaps it was just coincidence that the algal bloom happened to start at that moment. Or maybe the very 'spikyness' of the ammonia level produced by the pure ammonia was the problem - perhaps the stable, sustained dose of ammonia produced by urea breakdown doesn't encourage algae in the same way.

Any thoughts?

Shall we get the following posts out of the way now, so that we can have a rational, scientific discussion about it? 
"Eeeew, it's dirty!"
"Uggh - how disgusting!"  etc, etc, etc.


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## dw1305

Hi all, 





Dr Mike Oxgreen said:


> just a tablespoon or so of urine every few days.....Shall we get the following posts out of the way now, so that we can have a rational, scientific discussion about it?


I don't see any problem with it. I'm not an added ammonia fan, but if I was going to add ammonia, urea might be quite a good starting place. 

Urea is a lot less toxic than ammonia (which is why terrestrial organisms excrete it). Assuming the tank was planted during the initial urea phase, then the plants may have been mopping up the urea/ammonia, and ammonia levels may have been fairly low. Plants have the urease enzyme, but I think microbial action is more important in its break-down to ammonia.

I could see a mechanism where the change in ammonia source led to an algal outbreak. I think initially it would probably a take a while for the community of bacteria and fungi with the potential to metabolise urease to develop, and that would then be a different assemblage from the ammonia oxidising bacteria/archaea involved in nitrification (although some ammonia (and nitrite) oxidising bacteria must have been present, during urea addition, to create the NO2/NO3). 

Once you stop adding any ammonia source then there would be another change in microbial assemblage as the ammonia oxidising archaea became more important (this will occur both within the filter material and in the substrate).

cheers Darrel


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## Dr Mike Oxgreen

Just thought I'd update this thread!

It appears that my brown cotton wool problem has gone away, which is great.

I reduced my photo period down to 6 hours, and continued doing water changes every 2 or 3 days. I was using a small paint brush to gently tease the brown algae out of the hair grass, HC and Glossostigma during water changes, and sucking up some of the dislodged algae.

The brown cotton wool now seems to have packed its bags - it has disappeared even from deep down in the Glossostigma where I couldn't remove it.

I have had some very small, localised outbreaks of BGA (Cyanobacteria). These have not threatened to spread far so I think they're just temporary pockets as the tank settles and matures. I've found squirting a couple of millilitres of 3% hydrogen peroxide directly onto the 'algae' using a syringe held under the water works wonders and makes it disappear within 24 hours.

I read that the TNC Complete that I've been using can be dosed 3 times a week to approximate EI, so that's what I've been doing for the last week or so (except I'm using a 50% dose every day, which is easier to remember and gives a more even dosage). This certainly hasn't caused more algae, and I think the plants have speeded up a bit.

Here's a recent picture, complete with rubber decoy chili rasboras - I'm trying to get the chilies to relax and behave a bit more naturally. For that reason I'm also running with very dim lights at the moment, and hoping I can gradually ramp them back up. Also for the same reason I've allowed the hornwort to run riot.

I actually think there's virtually no algae of any type at the moment - happy days!


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## john dory

Hahahahahaha loving the fake fish


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