Bert H

Based on Scolley's results over at tpt with his gda/Maracyn treatment, I thought I'd do a little experiment of my own with Maracyn (erythromycin).

It's on one of my 50's which has a continuing minor problem with gda - day 4 or so after routine weekly maintenance, the front glass has a definite green sheen to it, and by day 7 its a little thicker. So I thought I'd use some Maracyn and see what happened.

Tank info: 50gal, 110W lighting via ahs lights/reflectors, pressurized CO2 around 30ppm via drop checker, dosed with modified EI (macros at water change weekly, micros M,W,F).

Maracyn used as follows: 4 packets day one (recommended dosage is 1 packet per 10 gallons), 3 packets for remaining 4 days. No other change to tank except for addition of Maracyn.

Results: on day 7 after my normal routine maintenance, there would be a fair amount of gda on the glass. I see none at the moment. I had left a small amount on the back and side walls, which now look a sickly green/gray.

Whether this will be long term or not, I'll know in a week or two.

But thought it was definitely interesting.

Any pharmacologists out there know if erythromycin is algaecidal?

Bert H

Follow up: one week later. Looks good so far. There is what I would call a 'base-line' amount of stuff on the glass, about the same as I am used to seeing with my other tank. It's certainly NOT the amount I had been seeing on a weekly basis from before. I'll let you know what happens in week 2.

hoppycalif

This is interesting! My thought is that many chemicals become toxic to different living organisms at sufficient dosages. So, the Maracyn may not be aimed at algae, but may become toxic to algae at higher doses. Just like Excel, in some ways. I have a bias against using antibiotics unless absolutely necessary, but if this is a cure for GDA my definition of necessity can become flexible.

Would the Maracyn be toxic to the fish and invertibrates at the levels that kill off GDA?

Bert H

As described above in my useage, I saw no ill effects to any of my fish or inverts. Fish consisting of guppies, sae, otto, and catfish. Inverts are snails, rcs, and amanos.

orlando

This is good info Bert, thanks.

hoppycalif

Bert, my try at this isn't working at all. In two days, two doses of Maracyn, I can see nothing at all different in the GDA. Since I suspect it could only be effective against the free swimming zoospores, I plan to wipe down my tank tomorrow and dose 2X dosage of Maracyn right after.

I want this to work so bad I can taste it!

mikenas102

Doesn't the use of Maracyn also kill some of the beneficial nitrifying bacteria in the tank and filter? If so, the resulting ammonia spike from killing the nitrifying bacteria could potentially bring on other algae problems. Green water for example is ammonia triggered. Am I guessing right here? Yes? No?

hoppycalif

I think this could happen, but I'm hoping the growing plants will be adequate for eliminating the ammonia quickly enough. I have been reluctant to use more than the recommended amount per gallon partly for that reason.

I'm too chicken to ever try this on a bigger tank, until it is settled that the method works, without causing other problems.

oregon aqua

ok im a little..... well...doesnt matter....but i have been following this thread closely because i have unbelievable gda and i want this to work really really really bad.
one point im confused on is...... if gda is a algae that is a spore and you cleaned it off the glass, and it floats in the water..... why doesn't my uv sterilizer kill it? from what i understand(in my limited knowledge)
the antibiotic should kill the exact same thing as uv's except uv's should be better at it.(understand this is from the hype i have read)

i do want this to work. i hate gda and i think it is the only algae that grows when the plants are happy. good fertz.+. good light..+.. good CO2?=gda there has got to be an equation that works. dont let me down hoppy (ohhhhhhhhh the pressure does it hurt?)

hoppycalif

GDA differs from the other algae that plague us in that it has zoospores, http://en.wikipedia.org/wiki/Zoospore, which are swimming creatures. When we wipe a young colony off the glass we are pushing a lot of the zoospores out into the water where they swim around looking for a place to colonize. They soon settle back on the glass and start reproducing again. For some time I have wondered why a UV unit wouldn't kill them, knowing that would require wiping them off the glass every hour or so to keep them in the water. I still wonder about that.

GDA can be eliminated with lots of hard work, and the UV method would just be another hard work way to do it, if it works. Being lazy I want a "magic pill" that kills them while I watch NBA games on the TV.