# Using Excel to kill algae



## dwalstad (Apr 14, 2006)

Emily6 said:


> I'll keep up with the Excel- I was only dosing one daily amount once a week. Maybe I'll go for daily now to knock back the algae.


Go gently with the Excel. I wouldn't use it any longer than I had to to kill your algae (It may damage the fragile growing tips of plants). A scientific study* showed that a green water alga was about 2-3 times more susceptible to glutaraldehyde than an invertebrate species. Glutaraldehyde reacts with the proteins of all organisms, but many algae have a more vulnerable cell wall than other organisms.

Also, Excel works very quickly, within minutes. Therefore, I would mix the dose you're using first with a larger volume of clean water and then pour this large volume throughout the tank.

Excel did help kill algae (slime and diatom stuff) in my 5 gal. I did a 5 day treatment. Before treatment, I could see oxygen bubbles appear on the algae during daytime. After treatment, none.

Water turned yellow from all the leachings from dead algae, bacteria, and plant matter. I did a couple water changes. The tank seems to have benefited from the Excel treatment.

*Sano LL, Krueger AM and PF Landrum. 2005. Chronic toxicity of glutaraldehyde: differential sensitivity of three freshwater organisms. Aquatic Toxicology 71: 283-296.


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## Emily6 (Feb 14, 2006)

That's very interesting- I was dosing once a week (only the daily amount) and getting brief results- the CO2 would go up and nothing seemed to get worse. Maybe several days straight would be the way to go, then let the tank get by on its own strength. I don't know my algae species very well (only common names)- did you notice any impact on fur algae? It's really the only kind I have a problem with. Also, with the proposed routine, do you foresee any issues with snails? (in case I have survivors from the move). Thanks for the advice!


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## dwalstad (Apr 14, 2006)

Emily6 said:


> That's very interesting- I was dosing once a week (only the daily amount) and getting brief results- the CO2 would go up and nothing seemed to get worse. Maybe several days straight would be the way to go, then let the tank get by on its own strength. I don't know my algae species very well (only common names)- did you notice any impact on fur algae? It's really the only kind I have a problem with. Also, with the proposed routine, do you foresee any issues with snails? (in case I have survivors from the move). Thanks for the advice!


I don't have fur algae. It may be have a tougher cell wall than the slimy stuff I had.

Snails and fish are fine following the treatment I used. I did lose some floating Frog Bit plants. It definitely killed them.

If you want to change treatment from what you are comfortable with, you might want to seek comments from others who've used Excel against algae. I am not an expert on this!


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## mommyeireanne (Oct 24, 2007)

I used Excel to kill Black Brush Algae. It worked really well the first time (10 days) not so well the second time (14 days). I think the BBA became resistant. ainkille I was having other issues in the tank and had my plant growth been it's usual jungle rate, then maybe I wouldn't have needed it in the first place. (I removed too many plants.) 
In the future I'll do all the other tricks for NPTs I read in the book or here: make sure you have some Aerial growth (trim side branches, not all the tops that come out of the water), do water changes, try a break in the photo period mid-day, add extra floating plants, consider feeding fish only once a day for a while, vacuum mulm, even run charcoal in a filter for a few weeks or so, if the issue is nutrient rich water. Once the plants get ahead you can do less work. 
For my tank, I think plant growth and pH are the keys. I have gotten the BBA in established tanks when I use only tap. Our water is extremely hard/alkaline and BBA loves it. I am using rain water now: 35g to bring my pH down a little in the 75g tank. I hope to not have many water changes this winter, and will probably buy distilled again if I need it. 
Guys in my plant club have BBA, too, and they use CO2 and Gluteraldahyde (the active ingredient in Excel) every day. But they generally only have a little; usually in one spot. I watched it take over every plant in my 10g tank once.


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## Dustymac (Apr 26, 2008)

I only tried Excel once and it was to kill some BBA. The next morning one of my favorite fish was dead. Was it the Excel? I have no way of knowing for sure but the fish was perfectly healthy the day before with a good appetite. Regardless, I won't be trying it again.


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## dwalstad (Apr 14, 2006)

The algae is back.

I think I"ll stick to floating plants/emergent growth and adding pots of healthy, fast-growing plants. Eventually, these measures will work.


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## Emily6 (Feb 14, 2006)

My CO2 spiked really high for two days after using the Excel, which scared me off the daily routine. Now, a week later, the algae is rampant! The only complication is that I removed a lot of the decaying floaters and trimmed back the algae-infested plants. Now is it getting too much light and too much nutrients without the floaters? Gah! I have more plants on the way but I'm scared to put them in lest they be covered in fur algae. :-(


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## Dustymac (Apr 26, 2008)

Emily,
I know it's little consolation but try to keep in mind the algae taking over your tank is busy eating itself out of existense. Eventually, if you don't feed it, it will exhaust an essential nutrient and start to die. One day it will look gray and then white and then invisible. 

I wouldn't remove any plants unless they are dying. The fur on it's own shouldn't kill plants. Each algae filament attaches to the plant leaf one cell to one cell with this attachment often only a few microns across. This means 90% of the plant is unaffected and can still do it's thing. 

The algae doesn't get any nutrition from this attachment; everything it needs has to come from the water. The algae does slow the plant down a little, competing for light, CO2, Ca & Mg, but the plant has the advantage in that it can get nutrition from the soil. Depending on the type of algae, it might not leave any scarring on the leaves when it's gone. 

Hope this is helpful,
Jim


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## Emily6 (Feb 14, 2006)

Thanks for your reassurance, Dustymac.  While I agree that ultimately the plants will make it, the algae is also filtering a bunch of the particulate matter drifting around onto the plants. This I think might affect them a bit more. However, I'm not going to remove plants. I think right now I'm going to do a 20% water change and sit back and wait for my new plants to arrive.


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## Dustymac (Apr 26, 2008)

One thing you can do on the larger leaves is reach in and rub them between thumb and fingers. This will break the filaments and dislodge any sediment. 

Also, your sediment might be diatoms. Good growing conditions for algae can extend to diatoms with the addition of silicates to the water. These diatoms float/propel about the tank until finding something to stick to. Unfortunately our municipal water comes from artesian wells which provide lots of silicates so changing water is one way to feed the outbreak. 

Hang in there,
Jim


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## baos (Jul 3, 2009)

dwalstad said:


> The algae is back.
> 
> I think I"ll stick to floating plants/emergent growth and adding pots of healthy, fast-growing plants. Eventually, these measures will work.


It's worked for me. I had a crazy outbreak covering a 90 gallon. And just about every other algae. All I have left is dust algae in a part of the tank that doesn't get as much circulation.


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## ZID ZULANDER (Aug 19, 2008)

I have used the overdose method more than once on different tanks. Works everytime. I also dose every day. Until I start to see the algae start to turn white.


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## Emily6 (Feb 14, 2006)

I got scared off after two doses- my CO2 indicator responded quickly from a dark blue (low) to a bright yellow (too much). I didn't want to kill the fish... was there something else at work here? It seems to have been a pretty major swing.


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## Philosophos (Mar 1, 2009)

Glutaraldehyde (excel) is extremely unlike to cause this change of color in drop checker you're talking about. Concentrations above 2ppm start to endanger the more sensitive organisms in our tanks such as shrimp, and excel is only about 3/25ths carbon. Standard doses aren't going to take you above 2ppm, and the short ~11 hour half life assures that it won't build up over time.

Keep in mind that it's no substitute for stable principles. It can help to fix mistakes, but depending on it to remove algae isn't a long-term solution. Dosing it into the column also isn't so helpful as spot treating; turning off the filter(s) for a couple of minutes and blowing it over the affected areas with a pipette is far more useful than dosing the entire column. I try to restrict my use of it to hardscape when spot treating; if the algae on plants can't be kept away through light trimming, then something else is wrong.

-Philosophos


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## dwalstad (Apr 14, 2006)

Emily6 said:


> I got scared off after two doses- my CO2 indicator responded quickly from a dark blue (low) to a bright yellow (too much). I didn't want to kill the fish... was there something else at work here? It seems to have been a pretty major swing.


Glutaraldehyde irreversibly cross-links the amine groups of proteins, so it is going to affect *all* organisms. Organisms with tough cell walls are more resistant; organisms with vulnerable proteins on their outer membranes will be killed. Many algae and gram-positive bacteria are vulnerable.

When these bacteria and algae die, their decomposition releases CO2. That's where the CO2 is coming from- decomposing dead bodies.

Glutaraldehye itself doesn't release all that much CO2. I calculated the *maximum* amount of CO2 that a 1.5% glutaraldehyde solution could release into the tank by recommended dosing. It was 4.1 mg/l CO2 for the initial dose (1:8,000 dilution) and 0.83 mg/l CO2 for the repeated, maintenance doses (1:1,600 dilutions).

GA (glutaraldehyde) contains 60% carbon. Some is, indeed, degraded to CO2. Leung (2001)* showed that (under his river/sediment lab conditions) that 51% of GA was degraded to CO2 and bicarbonates within 2 days. My calculations were based on a 100% conversion of all GA's carbon to CO2, which in the Real World, won't happen. 
________________
As to GA toxicity to organisms:

If you dilute a 1.5% (15,000 ppm) GA solution 1:8,000 for initial dose, you get 1.8 ppm GA in your tank.

Sano's 2005** study compared sensitivity of an algae, larval fish, and an invertebrate species to GA. Algal growth was inhibited by 1.7 ppm GA, while the invertebrate required 4.9 ppm. GA had a big effect on fish hatching (0.6 ppm inhibited), but older fry were not affected at all by 1.0 ppm GA.

*Leung H-W. 2001. Aerobic and anaerobic metabolism of glutaraldehyde in a river water-sediment system. Arch Environ Contam Toxicol 41: 267-273.

**Sano LL, Krueger AM and PF Landrum. 2005. Chronic toxicity of glutaraldehyde: differential sensitivity of three freshwater organisms. Aquatic Toxicology 71: 283-296.


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## nfrank (Jan 29, 2005)

Diana,
Your calculations are interesting. Since folks seem to have success with GA as a source of CO2, what do you think might actually be occuring in tanks without a large biomass of algae. Could it be the bacteria be contributing to the CO2 and how much carbon might that hold? e.g., have you ever calculated the biomass of bacteria in a tank, based on some nominal surface area assumptions?

Since bacteria may be affected, maybe a side benefit is preventing NH3/NH4 from conversion to NO3, making it easier for plants to uptake the N. 
With a little more chutpah or hubris, i postulate a "GA cycle" :
bacteria death ---> CO2 --> increased plant growth --> increased O2 --> more bacteria --> more biomass for CO2, etc.
--Neil


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## aquabillpers (Apr 13, 2006)

Excel/GA by itself is not a source of CO2. It is a source of carbon, as is CO2 itself.

To those who reported an increase in CO2 after using Excel/GA, how did you measure that increase? I think one needs a CO2 meter to do that. I don't think a decrease in pH by itself means that the CO2 has risen; other factors can cause that.

Bill


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## dwalstad (Apr 14, 2006)

nfrank said:


> Since folks seem to have success with GA as a source of CO2, what do you think might actually be occuring in tanks without a large biomass of algae. Could it the bacteria be contributing to the CO2?
> 
> I think that's entirely possible. After I treated my tank, the water turned yellowish. That means (to me) that DOC was released by death of tank inhabitants-- probably bacteria in the water, filter, substrate, etc. That DOC will subsequently be oxidized by new, growing populations of bacteria (or light) to CO2.
> 
> ...


Could be. The possibilties are endless.... :roll:


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## Aquaticz (May 22, 2009)

Hello,
Have not been active the last few months but I di have a lot of Excel experience,, mostly because up until yestarday I had non C02 tanks. BBA was one of the reasons I went with the C02 because BBA thrives, from what I have read on unstable C02 conditions. I have used Excel every day for at least a year..
If it is not completly gone in 2-3months I will do a hydrogen peroxide treatment. HTH


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## Barnsten (Jul 3, 2009)

I am currently using flourish excel to get rid of black beard algae in my 55 gallon tank. I went with a lower dosage at first as I have a bunch of cherry shrimp and mystery snails in the tank (as well as fish occupants) so I didn't want to harm anything with the initial dose. After seeing no signs of illness or stress I upped to dosage to the one on the bottle. I have been using it for about 5 days now, the BBA doesn't seem to be affected yet, but I have noticed some pearling on some of my plants this week, so I know the plants are enjoying the excel. 

Should I still keep removing overgrown plants or leave it as it is for now until the BBA starts to die off? 

The tank and plants are very healthy otherwise, I had the log floating on the surface up until last week (when I noticed it was covered in BBA, so I submerged it and started dosing with excel). I have the log in the tank for my 3 bushy nose pleco's to munch on. I have a lot of floating plants so the lower plants and the log do not get much light except in spots where the floating plants are not floating (of course, LOL). I also have a problem with some sort of filamentous algae (grows like curly hair), but it's not as bad as the BBA.


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## Emily6 (Feb 14, 2006)

So I found another post online regarding spot-treatment of Excel- they took an eye dropper (I used an oral hygiene syringe), turned off the filter and just spot-treated the worst areas. Then they turned the filter on half an hour later. 
I believe this helps to use less if you want by not diluting it into the tank. I tried it on my hardy (and VERY furry) amazons and it worked great! I used probably a double dose and got stellar results. I also added a daily does for two days after that and now my tank is more glamorous than it's ever been! The plants are growing like crazy and (two weeks later) there is very little algae to speak of. 

I'm calling this a success. I am not using it daily- just weekly, 1 dose. I invested in some cherry shrimp and an Chinese algae eater (who's very fat and happy). Here's hoping!


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