Blue Green Algae: Time for battle?

[beachkrazd]

I have had Blue Green Algae (BGA) in my planted 29 gallon freshwater tank for several months, so you may be wondering why I'm finally addressing the problem. Well, the short answer is that I was a newbie and didn't realize what I was dealing with. (I've had my fish/tank for less than 1 year.) I naturally thought the thick green slime appearing on my substrate and plants was a harmless 'green algae'. I hoped my 2 Mystery Snails would eventually help take care of the 'algae' problem. I also thought the strange 'earthy' odor from the tank which lingered on my arms after cleaning was a 'natural' smell due to my live plants and SeaChem fertilizers. (By the way, my husband -hates- that odor. Now that I know what causes the odor I really dislike it too!)

I eventually discovered through online forums that BGA is actually bacteria that utilize nitrate for energy, so no amount of adjusting lights, fertilizers and/or CO2 is going to help. I increased water circulation by adding a 2nd HOB filter on the other end of the tank (Aquaclear + Aqueon). All of my fish seem to love the new current and seem to be getting a good amount of exercise; I've noticed they are much more active now.

After removing ALL of the visible BGA last weekend during the weekly water change, plus the increased circulation, I hoped that I could manage to beat the BGA. But now, 7 days later, BGA is steadily reappearing on the Flourite substrate and plant leaves.

So now I have to face the facts - I think I may need to use antibiotics to beat this BGA infestation. I would like some help/advice about this because I'm concerned about my snails and shrimp being adversely affected by the antibiotic treatment. I have an empty Eclipse 6 gallon tank that could be used for temporary housing of the Mystery Snails, and a 10 gallon tank could house the Amano shrimp. I would also love to hear some of your personal experiences with battling BGA.Any recommendations for antibiotic choice and duration of treatment?Is there anything else I can do to prevent BGA from recurring?I would sincerely appreciate any information about this because I feel like I'm going into uncharted territory. I don't have much experience with using antibiotics in my aquarium and I really don't want my fish or shrimp/snails to be adversely affected. But at the same time I really want to be rid of this BGA so I guess I have to be willing to take that risk at this point.

In case anyone needs/wants it, here is some more information about my 29 gallon setup...

Tank inhabitants:
6 Lemon Tetras
6 Glowlight Tetras
3 Dwarf Neon Rainbowfish
2 Mystery Snails
1 Zebra Nerite Snail
4 Amano Shrimp
--Fish are fed once a day for 1 minute, snails fed daily in a separate container
--These fish have never been sick since I first started the tank in July 2009, so I'm -really- hoping that this antibiotic treatment doesn't hurt my biological filtration (I know that I'll have to be vigilant during antibiotic treatment.)

Plants:
Anubias congensis, hastifolia, and nana
Crypt. wendtii and lutea
Vallisneria
Flame Moss
--DIY CO2 with 2 x 2L bottles
--65W CF Coralife lighting + one 20W Life-Glo fluorescent bulb

Tank parameters: (liquid API test kit)
(These levels were taken during last weeks water change; these readings are in line with past readings too. I'll be rechecking levels tomorrow for the next water change)
Nitrates ~ 7 (less than 10 is the usual range; I check it weekly or bi-weekly) (I think I've read online that low nitrate could contribute to BGA, but since BGA utilizes nitrate it could be causing nitrate readings to be lower than they really are. But with my -reguarly-, weekly water changes and sparse feeding regimen I find it hard to believe that my nitrates could really be any higher than ~10 or 20 at the very most. None of my plants are dying so I know that is currently not a contributing factor to my nitrate levels. So of course, now I'm confused about the role of nitrate in BGA.)
Ammonia/nitrITE = 0 (of course!)
pH ~7.6
GH ~10-11
KH ~8

Cleaning schedule:
--Consistent, weekly 3-6 gallon water changes (15-30%) plus gravel vacuuming under objects and around plants
--I use a 60/40 mix of tap/RO water

[beachkrazd]

I posted this question about BGA a while back, but I'm here to provide an update! I did some more research on my own and decided to use the 3-day blackout method instead of antibiotics to get rid of the BGA (see links below).

Wednesday night:
I did a 30% water change (not the recommended 50%) before beginning the black out. I realized I had not cleaned out one of the filters in a while. Low and behold, there was a L-O-T of detritus stuck in 1 of 2 filters. I sucked everything out of the one HOB filter with a turkey baster, wiped down the inside of it with a paper towel, rinsed out the media, vacuumed the gravel, checked nitrates (about 10 ppm so I did not dose nitrates as was recommended in the links), removed as much BGA as I could, fed the fish, snails, and shrimp, turned off the DIY CO2, added an airstone, and covered the tank with 2 thick blankets (I later realized I could have also used black trash bags). I left it like that for 3 days.

I did not dose nitrates as is sometimes recommended because I think my BGA was caused by excess organics from the dirty filter. From my research BGA is either caused by 1. low nitrates (mine were always 7-10ppm so I was doubtful that was the cause), and/or 2. high organic compounds in the tank (e.g. very dirty gravel and/or filter, decomposing matter, etc.). By cleaning the filter I am hopeful that I have removed the cause for the BGA outbreak.

Saturday night:
Tonight was the unveiling of the tank! My fish were pale and 'out of it' but there were NO visible signs of BGA!! I also noticed that the funky smell from the BGA was GONE!

I didn't want to shock the fish with light so I let them adjust to light in the room before I turned on one of the tank lights. I fed the fish, snails, and shrimp, tested nitrates (still 10 ppm), and did another 30% water change. I trimmed some dead Vallisneria leaves and wiped away charcoal-colored sheets of dead BGA from the stems of my Crypt. lutea. (Edit: A few Crypt. lutea leaves started to yellow and die the next day after the black out ended, however the Crypt. wendtii and Anubias species are doing fine. Crypts can be finicky about changes in their environment.)

Also, a few days before the black out I decreased my lighting by removing the 65W CF Coralife fixture and added a 2nd 20W bulb (Aquaglo) + one 20W Life-Glo fluorescent bulb for a total of 40W. I have mostly Anubias and Crypt. species so I realized the 65W CF was unnecessary. I think I have about 1.6-1.8 watts per gallon now, which should be just enough for a low light tank with DIY CO2. I may not even need the CO2 now.

I would like to think that I have won the battle against BGA. I am going to make sure I stick to an alternating filter cleaning regimen to help reduce the risk of BGA coming back due to excess organics. I will update this post if the BGA comes back. I hope this information will help anyone else who may have to deal with BGA!

http://www.aquariacentral.com/forums...hp/t-1561.html
http://www.aquaticplantcentral.com/f...een-algae.html

[StanChung]

Congratulations on beating BGA, and I love the way you detailed everything you did meticulously and researched it quite thoroughly.