2007 Aquariumlife forum experiments
I have a 30cm cube that is currently over-run - and I mean shockingly over run - with blue-green algae.
I was planning to sacrifice the crypts and moss and dump in chlorine but I'd like to contribute with a Glut test on this tank instead if possible.
I was looking at merck (www.merck.com.au) as they have 100ml of 50% Glut for $32... or perhaps Dave I can buy some from your drum?
I have a couple of 18" tanks I can use for paired treatment/control toxicity testing on various species too.
My Snag biotope has a fair dose of cladophora in the gravel at the moment and I'd be more than happy to begin a low-dose Glut test on it also (not too high as I dont want to upset the rainbowfish)
Maybe its time to order those Werneri Dave and get a big shipment from you with a little Glut?
Last edited by Grubs; 05-10-07, 04:05 PM.
11-10-07, 12:43 PM
I've also just sourced some. $48 for 250ml of 25% from Merck. They also have a 1l of 50% available as an order in item (3 weeks) for approx $100 which would be 8 times cheaper again but I didnt want to wait nor commit that much $ to an initial experiment.
A GUIDE TO SAFE USE OF
GLUTARALDEHYDE
This needs to be emphasised:
Glutaraldehyde is nasty, nasty stuff. Careful handling protocols are required. The most toxic form is vapour in the air. It is very poisonous and corrosive.
My plan is to store my 25% concentrate at the lab I used to work in at Monash Uni - and mix up a 1 litre bottles of 1% as required and dose with that.
Day 0
This has been an uncontrolled backyard experiment in blue-green algae now for a couple of weeks. The floating mat of blue green is covering a Java moss "mop" that is growing on a wine cork.
I've tried 1% tea tree oil (DIY Melafix) at the normal conc 5ml in 40l for a week (no change) and at 40ml in 40l for a week with no impact. I though the antibacterial properties of teatree oil might knock the blue-green algae (cyanobacteria) around. - conclusive failure IMHO.
I've also tried dosing NO3 at 80ppm to see if nitrogen excess did anything - what you see is after a week - no effect - if anything its worse.
Volume is about 25l of water. I dosed 5ml of 1% Glutaraldehyde (2.0ppm)
Life in the tank - 1 angry Macrobrachium australiensis, snails (added every couple of days to feed the Macro), Cryptocoryne petchii, Java Moss.
This is as uncontrolled and unreplicated before/after scenario. The tank has looked like this for about 5 weeks now with no major change.
Temp: 20C (no heater)
CO2: None
pH: >7.8 (off the scale) was 7.1 before the BGA took over.
Last edited by Grubs; 12-02-14, 08:24 AM. Reason: added pH and Temp
11-10-07, 01:35 PM
In Australia 2% Glutaraldehyde is a high grade disinfectant (ie kills all possible bacteria, fungi, viruses, and some spores unless resistance has occurred).
So the anti-microbial effects of glutaraldehyde isn't in doubt but the observations from your experiment, Grubs, should be helpful in laying the ground for questions regarding bioequivalency of Excel and Glutaraldehyde. Other factors you might want to record are temperature and pH which will effect the rate and extent of response.
The concentration in the bottle is irrelevent. Lower concentration in the bottle = less hazardous to your health. The dose to the tank is larger to compensate as it is the tank water concentration that matters. I'll gladly match the dose level of others if you think it will help.
13-10-07, 05:17 PM
Day 2
I increased the dose on day 1 from 2.0ppm to 2.5ppm Glutaraldehyde to match the APC thread linked to above. [side note: If I was doing this again I'd stick to 2.0ppm and only dose every other day to give time for dead cells to break down] Photo above is today (Day 2).
Good News: Subjectively I see a slight decline in the BGA it has begun to slough off the crypt leaves. Some of the mat on the surface has gone and I can see the moss again.
Bad News: Mr. Macrobrachium is dead. *however* - by the smell of him I think he's been dead for a few days and may have even died during my elevated NO3 period prior to dosing with glut. He'd dug his way under a log and as I could see the claw poking out I assumed he was alive until today when I put in some food and he didnt respond. As this "experiment" has no controls we cant say the glutaraldehyde killed him - especially given that prior to dosing with glutaraldehyde I had injected 10 times the prescribed dose of "Melafake" tea-tree oil soln and raised the NO3 to over 80pmm (way over the test kit limits).... not forgetting that blue-green algae is toxic also!
I've put some caridina in another tank and dosed them up to the same level and so far there is no deaths and no change in their behaviour. I'm also now dosing up my big 600l tank to knock the hair algae on the head and the shrimp in there are fine also.
This emphasises the need for well designed experiments!
Last edited by Grubs; 12-02-14, 08:24 AM.
15-10-07, 09:42 AM
Day 4
Continuing the 2.5 mg/l dose each day.
Glass surfaces have cleared up phenominally. The hanging moss (its tied to a wine cork) is now visible again..... and I can see crypt leaves!
I've done some more research into the toxicity and persistence of glutaraldehyde and have kept references. The expected "life" of each dose in the tank is less than 24 hours. Dow Corning state 50% loss in just 10.6 hours and some independent research seems to go wth this too (2MB PDF - fig.11) So its important to note that each daily dose is unlikely to be compounding in the tank to higher and higher concentrations.
I also looked up toxicity concentrations. There have been many tests on cultured algae, daphnia, amphipods and some on fish. My mental summary of the reading was that often no effect was seen until concentrations exceed 5ppm and for most tests more like 10-50ppm. Test on algae (free-living green water type algae) were showing lethal effects below 1ppm. This makes me feel pretty happy about the 2.5ppm dose I'm using. Note however that one study does show that most eggs of steelhead trout failed to hatch at 2ppm.... so you wouldnt want to be dosing your breeding tanks when the parents are spawning.... (I doubt anyone would dose their spawning tanks with algecide anyway - esp as greenwater is a good source of food for newly hatched fry!)
...And lastly - at least one Glutaraldehyde manufacturer guarantee's their product is pure enough to be viable when stored for up to a year at room temperature but industrial grade would degrade a lot faster due to impurities. Every other manufacturer says to keep it at 4C. I suspect that if you are using it all up in 6 months its probably fine at room temperature but I havnt found numbers to back that up yet. Maintaining the purity by doing any dilution with distilled water obviously is important to maintaining the effectiveness. With the 1% solution I'm chewing though a litre bottle in under 4 days so I'm not too worried about it breaking down! At 1% my doses for a 2.5pmm solution are 6.25ml in the 25l cube, 100ml in the 4x2x2 and 150ml in the 6x2x2 each day (yes they are all getting dosed now
- no guts, no glory!). I'm thinking I'll move to a 2% dosing solution so that
I'm handling the concentrate less frequently. #74
15-10-07, 12:06 PM
No manual removal.
No water changes.
Just a little topup to re-submerge the BGA on the waterline on Day 3 (to kill it!).
Given the absense of any control treatment I wanted the only change to be the glutaraldehyde dosing.
The doses have been dosed into the water in the centre of the tank. I might drop the next dose onto some of the floating BGA mat for a quick kill.
The BGA is just slowly decomposing. I'm pretty sure at this point a siphon hose would clean up a lot of it as it is sloughing off the leaves.... but I'll let it run a few more days yet without touching it.
In my 6x2x2 'Dreamtime' - the BBA and Staghorn has gone a very pretty pink at all locations in the tank. Thread algae in the 6x2x2, and the cladophora in 'the Snag' look the same as before I started dosing. I have photos of all of these but I figured I'd wait until I had a weeks worth then post the sequences in one hit.
Day 6
Continuing the 2.5 mg/l dose each day.
Front glass and left side are now 100% clean. All of the patches of BGA that are left are where the algal mat was extremely thick to start with (e.g. on glass facing the window and on top of the floating moss).
Visible decaying mulm in the foreground now.
Interestingly the pH has returned to 7.0. It was more than 8 when the BGA was in full swing.
Here is the top of the floating moss - This was completely smothered at the start
Link to Day 0 post of BGA infested tank
Day 8 - FINAL
As this is an unreplicated and uncontrolled "experiment" our inference that changes in the tank are due solely to commencement of daily 2.5ppm Glutaraldehyde dosing gets weaker as time goes on. I think after 8 days its pretty clear what trajectory this tank is on now so we've reached the end.
The glass on the tank is pretty much spotless.
Snails are dropping eggs all over the place.
There are a few copepods and other planktonic critters in the water too.
Glutaraldehyde is used as a preservative because it penetrates cells and mineralises the protiens. So while it may be killing the algae in the tank it also retards any decompositon. There are places in the tank where the BGA mat was more than 10mm thick so these will take a very long time to break down. Time for some intervention - a water change and some manual removal. I'll probably then keep the daily doses going for another two days just ensure any freshly exposed algal cells get nuked. I still see occasional bubbles from the thickest part of the mat suggesting that algae in the middle might be alive (protected from the glutaraldehyde by the sludge above and below perhaps).
I will rescape this tank when I get inspired.
I'll post the pics of the other tanks a bit later
THE END
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