New High Tech Setup - Sudden Algae Outbreak Part 2

[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.

 

[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.

 

[Nelson]

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

 

[dw1305]

Hi all,

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).

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.

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

 

[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!

 

[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.

 

[dw1305]

Hi all,

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

 

[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!

 

[john dory]

Hahahahahaha loving the fake fish