BBA in CO2 Diffused Tank?

[mohican]

Doesn't CO2 help battle against BBA? I have noticed some black threads starting. Obviously, not something desired. I believe its my phosphates, any thoughts.
Lighting: (2) 36in HO fixtures run on siesta photoperiod. Approx 4hrs each cycle. Have been running 1 of 2 bulbs in 24" T5 HO fixture too.
Nitrate: 5.0 ppm
Nitrite: 0 ppm
Phosphate: 0.5 ppm
KH: 5dKH
GH: sorry don't have this test, need to re-stock.
CO2 infused with pH controller at 7.0 approx 3-5 bps.
Need anything else, let me know.
Thanks.

 

[blizowman1]

Yea what size tank is this? Does that mean you have 5 bulbs running on this tank?

 

[mohican]

125. Sorry for lighting. Was running 6 bulbs, 4-36 in and 2-24 in. Hope that helps.

 

[blizowman1]

That's a lot of light even for a 125 unless your running your co2 real high id say that's why your getting bba. How many hrs do you run these lights?

 

[mohican]

Approx 8 hrs, on siesta period. 4 in AM and 4 PM. I'm turning off the 2-24 in fixtures to see how things play out. Thing is, I've just now started to get it and just recently started co2 injection. Tank was running for over a year with 6 lights going and never had it, that's what confusing to me.

 

[aqua_chem]

What's your native pH without co2? Add anything that woulda drop pH lately?

 

[mohican]

Not sure what native pH is, it set on controller so it varies from maybe 6.9 to 7.1. No additives besides ferts. Using plant package from aquariumplants.com. (CSM+B).

 

[aqua_chem]

By native pH, I mean your pH before CO2 injection. If you've something changed that lowers your pH, such as driftwood or a change in your local water, then the pH set point will correspond to a lower level of CO2 than it did before.

Either way, I would try to lower your set point to increase CO2 levels. Also, what dosing regimen are you using?

 

[mohican]

My pH started at 7.8 and I've slowly lowered it to 7. The tank cleared for little bit then seems like it growing back. My dosing is about 3/4 tbsp of micro/macro alternated each day. I'm bad and sometimes never dose on a particular day due to general house/kids, oops.

 

[fort384]

Based on the stats you posted, that means your CO2 is only around 15ppm. That is a GREAT level for BBA

I would get it up to 30 or 35.

 

[mohican]

That was another question I had was how do you measure(ppm) co2? The chart method is the only way I know how but it isn't as accurate as drop checker. How did you get 15ppm?

 

[fort384]

CO2 ppm = 12.838*dKH*10^(6.37-pH)

So,

CO2 = 12.838*5*10^(6.37-7.0)

CO2 = 15

 

[mohican]

Thanks, I'm writing that in my journal.
Well, I guess I'll cut back on my lighting and just run the 2-36 in fixtures. I'll adjust my CO2 as well. Can pH be too low or CO2 be too high then?

 

[fort384]

pH can be too low and CO2 too high. But I think if you doubled it you will be fine. Doubling the co2 injection will only drop your pH to around 6.7 if your KH remains steady.

 

[mohican]

That's just what I figured. I forgot I have an aquarium app that has co2 on it and it seemed to be pretty close to your math. It uses KH and pH. Just set my controller to 6.7-6.8. I guess just wait and see how this plays out. Any other thoughts, please let me know!! Thanks for the quick responses.

 

[aqua_chem]

Sounds like a good plan. You should also look at removing whatever algae you currently have by whatever method you like (Excel, peroxide, scissors, etc).

 

[mohican]

Yea, its not bad, but wanted to get a jump start fixing things before they get worse. It's really just started on the driftwood. Thanks for your help. Should I have any concern over phosphate level? Plants don't use this do they?

 

[fort384]

Your PO4 level is a bit high for a high light planted tank but you aren't far off. Plants need phosphorus. They uptake it from PO4. You need some. I always try to keep my tanks around 0.1-0.2 ppm PO4.

 

[mohican]

I think since I have the dry mix, separating this element and dose it accordingly. At least I think I can.

 

[mohican]

Since I bumped up the CO2, should I just run the 2-36 in fixtures or can I also run the 2-24 in fixtures (just 1 bulb in each 24" fixture)? I hate to completely put the 2-24" fixtures away.