Brown Algae and Blue Green Algae vicious cycle

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gwlee7

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Rocky Mount, NC USA
I have a 29 gallon that I can't break a repeating cycle of brown algae followed by blue green algae.

My ph is 7.8 +/-
ammonia O
nitrIte 0
nitrAte < 20 ppm

I have 2 watts per gallon of light. My plants are two bronze wendtii, an amazon sword, a couple of other crypts, a little bit of dwarf hair grass, and some hornwort.
I have put some root tabs in the substrate (which is pool filter sand)

Here's how it works: I started getting brown algae so I increased the amoount of light from 10 to 12 hours and the brown algae went away and I started developing BG algae. I started putting a "siesta" of two hours to break up the BG algae cycle but it did not work. Ultimately, I blacked out the tank for 96 hours (four days) and the BG algae went away so I set the lights back at 10 hours total with a two hour break.

The brown algae almost immediately came back and began covering everything. I increase the amount of time that the lights were on and now there is both brown algae and the freaking BG algae is starting to come back too.

I don't have any problems at all in my 30 gallon long that has similar watts per gallon, substrate etc. (the plants in there are thriving and have to be pruned) but I also realize that it is a shorter tank and therefore has a little stronger light intensity.

I have not been able to get an accurate measure of phosphate but have put phosphate absorber in my filter just in case.

This is driving me INSANE.
 
The problem is that BGA is not an algae at all, it's a bacteria. Light does impact it's growth which is why it probably gets worse once your keep your lights on for a longer time.

You have 2 options for getting rid of the BGA:

A. Do a 3 day blackout. No light at all. It will impact your plants a bit but they should recover. You used this method and it didn't work. :/

B. Treat your tank with Maracyn which is an antibiotic and is also known as erythromycin.

1) Clean out all visible bacteria you can.
2) Treat for 5 days with 1 tablet per 10 gallons. Crush it first to help it dissolve.
3) Clean up all the dead algae that will float into the water everyday. This is very important because it will make your ammonia and nitrite levels rise as it decomposes.
4) Do a thorough gravel vac and water change at the end of the treatment. 25-50% Water change.

Also, once you've got your tank back in balance, keep your lights on for ~10 hours with a break in between of 3 or more hours. This keeps the algae at bay without harming your plants.

HTH :)

~Nisha
 
I realize that BGA is a bacteria and also, that "brown" algae is really diatoms and not truely algae either. What is so frustrating to me that I seem to be able to get rid of one but then the other crops back up. I can get rid of the BGA by blacking out the tank but then the brown diatoms start up agian. I can increase the duration of the light and then the BGA starts up again. I guess maybe I will have to increase the light and treat the tank with the maracyn but, I really don't want to put chemicals in there :no:
 
I understand your frustration. I was very reluctant to put any chemicals in my tank too but finally used Maracyn. I've never seen my tank so crystal clear. All my fish are incredibly healthy even after the treatment. No deaths, no illnesses.

I think Maracyn is a good idea to use once you've tried everything else. The BGA shouldn't come back again unless you reintroduce it in your tank through new plants or infected nets etc. This route should help you get rid of the rough cycle you're in.

In the end it's your decision. Good luck. :)

~Nisha
 
As stated above, use Maracyn. In some cases you only need to dose once or twice before the algae disappears. I would also suggest using Purigen in your filter instead of carbon.
 
okie dokie. Will have to give it a try. What's the best way to "sterilize" nets? Just run very hot water over them and let them dry? A very mild bleach solution?
 
NO BLEACH!! Sorry to yell but it's really really hard to get all of the bleach out of nets. Buy some Jungle Net Dip (or any brand of Net Dip) and use that for disinfecting your nets.

btw I asked in this forum about disinfecting plants before moving them to avoid spreading the cyanobacteria and was told it wasn't necessary as the conditions are what cause it to grow and not the actual bacteria. IOW if the conditions aren't right in my other tank it won't grow no matter what. I didn't transfer the plants after all but I did transfer a few fish. HOWEVER I didn't do anything other than reduce lighting time on my tank and my cyanobacteria has mysteriously disappeared for the most part *knocking furiously on wood*. All I did was talk about what I was going to do-I never actually did anything.
 
With the exception of Hornwort, you have pretty slow growing plants, add more stem plants leike Hygrophila polysperma, Hygro. difformis, which will be better able to compete against algae for nutrients.

In a well palnted tank, you will usually (in my experiance) have near zero nitrates. Do you add co2 at all?
 
I think I can see what your problem is. Most of your plants, the crypts, grow slowly. Meaning that there'll always be an excess of nutrients in the water.

Water sprite is good too, and floating plants are good for absorbing all those extra nutrients. Stay away from crypts and swords. Rotala indica grows very fast in my tank, as does hygro. ploysperma....

Just do a google search on what kind of fast growing plants will do well under your tank's stats (temp, PH, light...) and plant a jungle! Buy a variety of plants, as not all plants will do well in your tank.

How recently has your tank been set up?

I'm sure you already know not to add any more ferts... Those root tabs. What's your readings from the tap? After adding an airstone to dissipate any CO2... Don't give up, we've all been there, frustrated about our tank's algae problem. I know I have.. :angry:
 
okay gale I HEAR YOU!!! NO BLEACH :lol:


am on the way to get some faster growing plants now. I have 2 watts per gallon of lights and no C0 2 as of yet. Haven't needed it in the 30 long and was hoping not to in this tank either.

Thanks for all of the encouragement. I will beat this yet and then be able to help someone else.
 
Update:

Just got back from LPS and have purchased a gob of rotala indica and wisteria. I will continue to update.

Thanks
 
Good, both those plants are fast growers they will help, if you have a good quantity. Basiaclly you want enough fast grwoing plants to start wityh so that they can grow without being overtaken by algae and that means them using the nutriesnts that otherwise algae would use to grow.
 

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