# [Wet Thumb Forum]-Killing BGA



## dwalstad (Apr 14, 2006)

Hi Folks,

Despite what I wrote in book, I confess to using "shortcuts" for killing some forms of algae. 

For example, I've used antibiotics twice recently for quickly killing Blue Green Algae (BGA). Erythromycin (sold as Maracyn II) works so well for me. I use the tablets at slightly less than recommended dose, and the Blue-green algae just disappears in a few days. Plant growth-- no longer smothered in the stuff-- picks up immediately.

As to green water algae, I've struggled mightily with that in some of my previous tanks. If I had that vexing problem again, I would stop "fussing" and just kill it with a UV sterilizer!


----------



## javalee (May 8, 2006)

Diana, just a quick correction, Maracyn II is minocycline. Maracyn I is erythromycin. 

Thanks for the post! I happen to have a chronic battle with BGA in my tank. I'm getting tired of rubbing it off the otherwise healthy leaves and the glass! I was wondering if minocycline (Maracyn II) would be effective, but since one drug covers gram negative bacteria and the other is for gram positive, I can see that erythromycin (Maracyn I) must be the one.


----------



## Inquisitive (Nov 7, 2003)

would either of these remedies be effective for green water?


----------



## javalee (May 8, 2006)

Inquisitive, these remedies are antibiotics---made to kill or inhibit bacteria. Green water is caused by algae so, no. But that's why Diana suggests the UV sterilizer, above, for green water.


----------



## dwalstad (Apr 14, 2006)

> Originally posted by Inquisitive:
> would either of these remedies be effective for green water?


Antibiotics won't kill green water. Robust colonies of floating plants, UV sterilizers, diatom filters, and daphnia cultures have all worked with varying degrees of success. I'd go with the UV sterilizer for a quick, sure cure.

Antibiotics like erythromycin and kanamycin (for killing gram-positive bacteria) will kill BGA. BGA is actually a cyanobacteria, not algae.

Javalee-- thanks for the correction about which Maracyn.


----------



## Inquisitive (Nov 7, 2003)

yeaaaaaa, i knew that.......dont tell my old college advisor
thanks guys


----------



## flagg (Nov 29, 2004)

Your secret is safe with us, Inquisitive.


----------



## Shariukas (Nov 29, 2005)

Hi all.

There's another option for fast destruction of BGA. In my place, one needs a doctor's prescription to buy erythromycin at pharmacies.

Hydrogen peroxyde (H2O2) can be used to fight BGA. 20 - 25ml of 3% solution for 100l should be applied daily, for up to 2 weeks depending on the situation (sorry guys, i don't know the quantinities in US units, hope that won't make much trouble). Fish are capable of surviving dosing up to 40ml for 100l without any harm, but if you have susceptable plants (mostly those with feather-like leaves), 20ml for 100l is recomended dosage. If possible, apply the dose directly to the BGA infected area.

The end product of peroxide is water and oxygene, the dose completely decomposes during 24hrs. There's no need to do major water changes after treatment. Charcoal is of course useful to absorb toxins released by dying algae.

Any comments about this?


----------



## Tonka (Mar 20, 2004)

Wow! This seems like a great idea. Anybody else have experience using hydrogen peroxide? Any toxicity to scaleless fish?


----------



## Erin (Feb 18, 2005)

> Wow! This seems like a great idea. Anybody else have experience using hydrogen peroxide? Any toxicity to scaleless fish?


Here is an excellent article on the uses and dangers of using H2O2 by Giancarlo Podio http://www.gpodio.com/h2o2.asp, whom I consider to be quite the expert on most things aquatic. He gives wonderful concise information. You can also find information about the uses of H202 at http://www.thekrib.com/Plants/Algae/hydrogen-peroxide.html. Tom Barr is another plant expert with great information.

Hope this helps,
Erin


----------



## GhostMan (Jan 15, 2006)

Hi all,

I had this problem in one of my tank with BGA and this was very annoying. It was always coming back after I cleand the tank. I changed water did not do anything to it. The waterparameters looked nice, and the water I got from the tap is extremly clean it comes from a water purifying plant. So bad water quality and BGA I am not convinced that is the reason for it.

Then later I was at this Norwegian forum that we where discussing this BGA phenomena and some people was talking about the possibility of allelopathy and that Egeria Densa should do the trick against BGA. So I put some Egeria Densa in mye tank and the BGA slowly died from the tank and I have never had the problem again in any tank that got Egeria Densa.

I don't know if this is a coincidence of not but it was very striking that the BGA died of after I got Egeria Densa in my tank.


Regards
GM


----------



## Shariukas (Nov 29, 2005)

Hi.

Erin C. Thanks for great links, that helped much.

GhostMan, if my memory serves me well, the effect of Egeria Densa on BGA is also discussed in D. Walstad's book. Your experience prooves it. Thanks for a post.

Good luck.


----------



## jaybird002 (May 12, 2006)

For me, the deciding factor in the battle against blue-green algae was a vine-type ivy, a regular houseplant. I put a couple of stems in the water and let it grow emersed outside the tank. As soon as the stems sprouted long roots, the BGA receeded. I also added charcol to the filter, reduced the light, and added a lucky bamboo, but I think the ivy was the major player. Although the stems barely touch the water, the network of roots is huge, some even growing into the gravel.

The ivy apparently deprives the BGA of some vital nutrients but does not affect the floating hornwort, which grows so fast that I have to throw some out every month.


----------



## javalee (May 8, 2006)

I wonder why my BGA is growing _on_ my hornwort and all over the hygro next to the Egeria densa. My nitrate is usually around 3ppm. I wonder if it's worth pushing it up. I even have strong circulation; I read that is supposed to help.

I introduced the BGA by adding the hornwort with BGA already on it, and ever since then its grown in clumps here and there, spreading by contact. Now that it's on the Bacopa I'm really frustrated because I can't really manually remove it from that. I was hoping to avoid the antibiotics. Maybe I'll try the peroxide. I already put the hornwort in the sink with some water and peroxide. I'm just nervous about adding it to the tank.

I wonder if it's spreading now because my tank has filled in a lot and the light isn't as strong on the plants underneath. I'm wondering if thinning and pruning would be helpful---adding more light for the plants to take off, or if it would be worse---removing thriving plants and thus providing more nutrients for the BGA? This stuff is persistant!


----------



## dwalstad (Apr 14, 2006)

BGA is tough. I didn't find pruning, thinning, water changes made that much difference. And hand removal only seemed to spread it, as little bits of BGA broke off and settled on other plants.

After treating with antibiotics in two of my tanks, the plants picked up and the BGA has not come back...since several months now. I know antibiotics are a crutch, but it seems to be a painless remedy.

I'm careful now not to prune plants too heavily. Heavy pruning sometimes seems to invite problems.


----------



## javalee (May 8, 2006)

Thanks Daina. I can see what you're talking about. I rubbed some off leaves last night and noticed blue-green slime floating around the tank. Only 30 minutes later, the clumps had re-established themselves in areas on the tank where it had not attacked previously. That was a bad move on my part.

I'm also thankful for your comment about heavy pruning. This is my first thickly jungled tank (testament to the effectiveness of the Walstad natural aquarium) and I let it get out of control, the BGA took over some thick areas, and now I was about to whack it back. I think I'll have to start doing more regular conservative pruning rather than cutting back severely when the fish no longer have room to swim. I also need to get some MaracynI. I give up!


----------



## Mr Fishies (Apr 9, 2006)

> Originally posted by Tonka:
> Wow! This seems like a great idea. Anybody else have experience using hydrogen peroxide? Any toxicity to scaleless fish?


I just recently gained some personal insight into using H2O2 to stop algae in my tank. Here is a link to my summary.


----------



## javalee (May 8, 2006)

I beat the BGA while waiting for the LFS to order MaracynI! I wanted to share my mostly-natural success.

My tank was becoming jungle very quickly and light was being blocked so, all in one day, I
1.) pruned and removed some floaters
2.)removed all removable BGA-infested plants (hornwort, anacharis, water lettuce, and the tops of the cabomba) from the tank and put them in the sink for a cleaning in chlorinated tap water. Swirled them around a bit and "stroked" the BGA off. Then returned them to the tank.
3.)*Added 3 adult guppies* since I couldn't get my nitrate levels above around 2ppm with my 3 fish, shrimp and snails. I think this was the most important part. This added ammonia and CO2 to boost the plants over the BGA. I've always read that low nitrate levels give BGA an advantage.

So now the BGA is practically gone. Just a few managable spots here and there---very small and mostly pretty swirls on the glass. I've watched it die off of a rooted cabomba that was previously clotted with it!

I'll have that MaracynI on hand now, but I'm glad I got off without using it this time. So check your nitrate levels!


----------



## Piscator (Apr 16, 2006)

Greetings all,

... well, I had a tank badly infested with BGA for a year or so. Snails and algae eating fish didn't seem to touch it, and CO2 seemed to make it worse. I reasoned that if hydrogen peroxide would get rid of it, maybe strong aeration would do the trick.So I put aeration stones in each corner of the tank and the BGA was gone in about 6 weeks. Apparently aeration, aswell as increasing oxygenation, reduces the availability of phosphates and iron (http://www.malibuwater.com/Aeration.html), which perhaps encourage the BGA.

Since clearing the BGA the stem plants have taken off in the tank, so the plan is to now gradually reduce the aeration in the hope that the BGA doesn't come back.


----------



## dwalstad (Apr 14, 2006)

This is great information! Thanks for the post.


----------



## imported_kram (Apr 30, 2005)

Do the antibiotics kill the benificial bacteria that we need???


----------



## aquabillpers (Apr 13, 2006)

> Do the antibiotics kill the benificial bacteria that we need???


Not in my experience.

Bill


----------



## Piscator (Apr 16, 2006)

Well, folks, over a year ago, I metioned in this thread that I had some success reducing BGA with strong aeration as a perhaps safer subsitute for hydrogen peroxide. Anyway since then we have moved into an area with a surface runoff water supply, whereas our old supply was ground water with quite a bit of phosphate and iron in it. In retrospect is seems that those elements were the cause of what was a recurring problem. The same tanks, without cleaning out, quickly lost the BGA when filled with the new, soft water.

Looking back it is of interest that the BGA was only a problem in the rearing tanks which have sub-gravel filtration and plants with soil in pots. The El Natural tanks were free of BGA. The El Natural tanks' substrate was soil and clay which perhaps was binding the phosphate and iron. Also, there were fewer water changes which, of course, would have refreshed the supply of phosphate and iron.


----------



## strange_screams (Apr 10, 2005)

ive had a problem with some sort of algea that i think ya'll are discribing, for about 6 months with my first planted tank, im still working on it, but its almost gone, i added about 10 baby nerite snails and three black mollies, one of which was pregnant. Took off the mini filter and added a desk lamp worth 20 watts. It had developed a thick "carpet" all over the plants but when you wiped it away they were seemingly healthy underneath....its been a week now and only little clumps are left, and my plants are pearling without any addition of co2


----------



## DataGuru (Mar 11, 2005)

Here's a more natural approach
http://www.xs4all.nl/~buddendo/aquarium/redfield_eng.htm

by altering the ratio of nitrAte to phosphate

Here's another study on it
http://digital.library.okstate.edu/OAS/oas_pdf/v68/p39_44.pdf


----------

