# Plant leaves turn black



## rich815 (May 21, 2008)

I suspect lack of CO2 to those leaves. And since it looks like you have enough CO2 based on the drop checkers it's likely then due to insufficient circulation and flow of the CO2 to certain parts of the tank. I used to have that on my fern leaves, got myself a Koralia 2 and made sure my flow was everywhere in the tank and it's now practically non-existant.


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## rich815 (May 21, 2008)

Also noticed you do not dose for macros (NPK) so that might be a factor as well.


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## pdhooge (Sep 25, 2008)

Hi Rich, thanks for your reply, I will see what I can do to get more flow. I tried it before but I didn't get the impression it helped , I also bought a koralia some time ago.
About the NPK, I used to dose that because my PO4 always read 0(even with 3 different testsets ), but it looks like the smallest dosing of excel Phosporus made things even worse... do you think overdoing excel could solve it, I've read some threads about it?


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## abcemorse (Jul 24, 2008)

I've had (and continue to a small degree but am winning) that problem. Spot treating with your daily dose (OD) of excel works well, just turn off circulation for 15 mins or so. You will probably have to cut some of the affected leaves away. Also, don't rely too much on the KH/pH model for CO2 levels, phosphates and other stuff in the water can skew your results. Drop checkers are more accurate, not perfect, but better. I was using pH to measure CO2, thought it was about right, got a drop checker and found it was only maybe 5-10 ppm!


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## die2win (Aug 10, 2008)

I've had this problem also, mostly on my swords. Seems to have gone into a holding pattern (not getting worse) since I added the 2215 canister filter. Only change has been the balanced current in the tank. roud: This is the most frustrating thing to see on the plants IMO. :angryfire


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## pdhooge (Sep 25, 2008)

thanks for the comments die2win and abcemorse, last week i have replaced my in-tank co2-reactor by an external Dupla-S, connected to an additional small pump. 

Together with the powerhead I have reinstalled it will add some more flow to the tank.
I will see what happens, I am also starting to wonder more and more if this really is an algaetype at all, it doesn't fit any of the common found algaetypes described anywhere.


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