# Nitrates and Algae question?



## t-bore (Apr 21, 2010)

In my 50G planted I am usually battling algae (I think BBA). I have pressurized co2 which turns on an hour before the lights turn on and turns off 10 minutes before the lights go off. My drop checker is usually a light green with slight yellow by the time the lights go out. I run an air stone 2 hours after the lights turn off for 8 hours. 96 watts of light 7 hours a day. 

I EI dose
KNO3 1/2 tsp mon wed fri
K2SO4 1/8 tsp mon wed fri
KH2PO4 1/8 tsp mon wed fri
CSM+B 1/8 tsp tue thur sat
A 50% water cahnge on Sun

I tested today and 
GH8
KH5
PH7
no ammonia 
no Nitrites
but approx 25 on the Nitrate scale.

Is this Nitrate level causing the algae and how do I lower it? Should I cut down the amount of KNO3? Or just possibly the drop checker is not reading correct and there isn't enough co2?


----------



## aquafeet (Jan 18, 2011)

Maybe try running the lights for no longer than 4 hours at a time with downtime no less than 2 hours - so if you want a total of 7 hours of light for your plants per day, try doing it in 2 shifts of 3.5 hours with a minimum of 2 hours without lights on. I've had good luck with that. Apparently, the thinking is that it takes 4 hours for most algaes to start using light, while it takes only a few minutes for most other plants to start.

You may have to do a black-out (cover the tank completely) for several days to get rid of the algae you have, but I'd give the shorter lighting sessions a shot first. Or an alternative might be to keep the tank room dark until the algae is gone so that when the tank lights are off, the algae won't have ambient light to use either.

With regard to your nitrate question, I don't think 25ppm would be a concern with repsect to algae growth unless there are other contributing factors (like too much light, too much ferts, etc.), then any nitrates will encourage algae growth. Eliminate other factors and the nitrates will encourage plant growth rather than algae growth.


----------



## ug.mac (Jul 13, 2010)

BBA is CO2 issue. I had them in my 29 gallon before. Reducing light or/and photoperiod won't help to kill BBA since BBA even thrive under very low light. Excel spot treatment will kill them temporarily but increase your CO2 and keep it stable will solve BBA. Forget about color in CO2 indicator, I use them for decoration only, same as bubble counter, because none of these will tell you how much CO2 *you need*.

ug.


----------

