# too much light causing bba?



## james1542 (Sep 8, 2011)

In my experience it's a nutrient imbalance, and while I'm not sure if it's N or P, I'm guessing it's P. It seems that some tap water contains extra P or N that is giving the BBA an advantage. If you can get RO water and add the minerals, and the proper balance of ferts, the BBA will quit growing. Also your photoperiod is a bit algae friendly. I'd cut that down to 8 or 6 until your problems go away. Start dosing the Excel at double the recommended dose and you the BBA will burn itself out. Some stem plants burn out from this method too.


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## Hoppy (Dec 24, 2005)

BBA isn't caused by a nutrient imbalance. It is a result of having plants that are not growing at the rate the light pushing them to grow at, and that is usually because of a shortage of CO2. You probably have about 60 micromols of PAR, assuming that the light fixture is polished stainless steel, as it is described to be. That is too much light to do without CO2, although Flourish Excel or API CO2 Booster may be adequate as a substitute. Once you supply the carbon the plants need, they should grow much faster, and you will then need to dose NPK and trace elements, preferably per http://www.plantedtank.net/forums/showthread.php?t=21944 If you can't do that, you can put a layer of fiberglass window screen, from Home Depot, over the top of the tank, or over the light, which will reduce the PAR by 40%, leaving you with about 35 micromols of PAR, which will be low enough that you may not need either the carbon or the fertilizing.

Now that you have BBA growing, you have to remove or kill all of it to get rid of it, or it will continue to grow no matter what you do.


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## tex627 (Jan 11, 2009)

I agree with Hoppy. Dose excel if you don't have co2. Another thing to look into is how old are your lights? If may be time to change out your bulbs soon.


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## flesxruoyxllik (Oct 15, 2011)

lights should still be fresh i got them this summer how often should i replace them


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## james1542 (Sep 8, 2011)

Hoppy said:


> BBA isn't caused by a nutrient imbalance. It is a result of having plants that are not growing at the rate the light pushing them to grow at, and that is usually because of a shortage of CO2. You probably have about 60 micromols of PAR, assuming that the light fixture is polished stainless steel, as it is described to be. That is too much light to do without CO2, although Flourish Excel or API CO2 Booster may be adequate as a substitute. Once you supply the carbon the plants need, they should grow much faster, and you will then need to dose NPK and trace elements, preferably per http://www.plantedtank.net/forums/showthread.php?t=21944 If you can't do that, you can put a layer of fiberglass window screen, from Home Depot, over the top of the tank, or over the light, which will reduce the PAR by 40%, leaving you with about 35 micromols of PAR, which will be low enough that you may not need either the carbon or the fertilizing.
> 
> Now that you have BBA growing, you have to remove or kill all of it to get rid of it, or it will continue to grow no matter what you do.


Maybe it's not an imbalance, although scientific studies have shown that freshwater systems are P limited not N limited. But the OP just told us they have high nitrogen in the tank. I'm not familiar with this light but it appears to be a bargain priced NO flourescent, with a mere 68 watts on a 75gallon tank-so low light. I don't think this is a case of too much light, I think it's a case of too much ferts. I have seen BBA outbreaks where changing the water, makes it worse, indicating that the tap water providing it with nutrients. I've also seen cases where changing to RO water, with no ferts, makes it stop spreading completely-even under very high lighting. The bottom line is-It's all about balance and everyones situation is going to be unique. Since you don't want to change your setup, I would OD on Flourish excel, reduce the photoperiod to 7 hours, get those nitrates out of the water, if you have high nitrate source water you might need to change to RO, if you have too many fish in the tank causing this, you may need to cut back severely on their feedings/and or thin the herd.



tex627 said:


> I agree with Hoppy. Dose excel if you don't have co2. Another thing to look into is how old are your lights? If may be time to change out your bulbs soon.





flesxruoyxllik said:


> lights should still be fresh i got them this summer how often should i replace them


The impression I get is that aging bulbs doesn't make the algae grow. It's true as they age, the spectrum can change, and the output can drop, which can indirectly lead to algae as things get out of balance, but NO flourescent bulbs should be fine for at least 6 months, but if your on a budget and you are diligent you could get by for 1.5 years.


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