Fluctuating CO2 levels and algae

[tyrophagus]

Hi
My tank is doing relatively well but I'm getting some algae, multiple types in low quantities

I'd appreciate some advice. I have looked at James planted tank algae page. To avoid algae I need lights that are at a reasonable PAR, good flow, optimal levels of nutrients and high co2. I think I meet all these requirements. I am concerned that the CO2 is fluctuating between a low and high point and is not constant enough.

I think I have BBA, Cladophora, green spot algae and Spirogyra. I'm losing quite a few crypt leaves as well which are melting.

They are all present in very low quantities but I'm concerned that this may be a serious problem soon.

Tank Stats

I think i have good flow - powerhead + 700 l/hr (1800 l/hr rated eheim) via a spray bar across the back of the tank. Plants move gently in the flow.

The tanks 180l and I'm dosing EI for a 250 liter tank.

My lights are are on for 9hrs And I have measured the PAR levels which are approx. 80 at the surface and 30 at the substrate.

CO2 is timed to come on 4 hrs before lights on and goes off about 4hrs before lights out. The rate is high - between 10 and 15 drops per second. Difficult to count accurately. My drop checker is dark green before the co2 starts and by lights on it is lime green and then slowly goes yellow. My fish are fine but I have lost some shrimp from time to time. By lights out the drop checker is still a light yellow to lime green.

So what do I do? Increase my flow, add phosphate for the green spot algae. Is the fluctuation between dark green and bright yellow for my CO2 a problem?

Cheers

Sorry best pic is from camera phone

 

[andyh]

Hey there!

Nice looking scape dude!

I think first and foremost your problem is flow and then light.

You should be aiming for at least x10 turnover of your tank.
On my 180l i am running (2 ehiems (1x1700lph & 1x 750lph) plus a Hydor Powerhead 900lph)

If you are pumping in that much CO2 you should be fine, hence why i am suggesting it could be a flow problem.

Lights - I cant work with PAR values (as i am not that clever!) how many watts have you got above the tank?
Without knowing i would suggest reducing your light, either by lifting you light higher/reducing tubes etc, until you get things under control.

Also are you completing regular water changes?

Andyh

 

[Garuf]

Also, try changing your co2 to a higher level coming on 2 hours before lights and going of an hour before. You might find 4 hours before lights off was a little too ambitious as that's surely nearly half the photoperiod?

 

[Anonymous]

IMO 15 b / s it's huge amounts of CO2. I think you are fine with less ~ 4 - 6 b / s started 1 hours before the lights.
Try to see if lowering CO2 you still got GSA, if so your plants needs more ferts.

 

[Mark Evans]

increase co2 or distribution of co2. and half the output of what ever lighting you've got....simples.

lower that drop checker near to the substrate to.

 

[CeeJay]

Hi all

increase co2 or distribution of co2. and half the output of what ever lighting you've got....simples.

Couldn't agree more.
That one liner should be a sticky

 

[nry]

Knocking the lighting period down would be a good start too - 9 hours is pretty long, 7-8 is fine, even 6 is manageable.

How long has the tank been setup for? I had similar issues myself with a newly setup tank - once my filter matured the algae disappeared very quickly.

 

[CeeJay]

Hi tyrophagus

Try to see if lowering CO2 you still got GSA, if so your plants needs more ferts.

I'm afraid this is the last thing you would want to be doing.

I think I have BBA, Cladophora, green spot algae and Spirogyra. I'm losing quite a few crypt leaves as well which are melting.

From the above quote, you clearly do not have enough CO2 or circulation is poor. Most of the above algae is CO2 related, plus the melting can also be attributed to poor CO2.
So I would not even think of lowering the CO2 at this stage, but concentrate on your distribution of it.

By the way, I'm liking the scape

 

[Anonymous]

Chris as far as I see his aquascape is pretty flat, I don't think there are many issues regarding the flow. Still I think 10 to 15 bps is too much if of course the dissolving rate is optimal, if not there's an issue.

I've found out after my vacation that GSA/BBA is thriving (well only on glass and decor) even in excess nutrients (I thought only in a low nutrient tank) with plenty of light and poor co2 distribution. So now I have 0.5w/l t5s from 1w/l and I've optimized the co2 distribution - changed the JBL reactor with a glass diffuser and added a recirculation pump to help the CO2 distribution. After 4 days after cleaning the glass and soil no algae issues. I'm working with 2-3bps CO2 on a 110l tank, I find it enough because I let it ON 24h. Prior this I had no issues with plants but I've found that now all the Rotalas are thriving, most of them were going horizontal, now with co2 flow optimized they are all growing upwards. I've also found out that the recirculation pump with a vertical spray bar is more efficient than my wave pump. I've made the holes on 3 sides and it creates small whirlpools in my tank, I can see them on the surface. (the green thingy on the right http://i51.tinypic.com/2mpla3a.jpg is the pump's spray bar). I've also did some small holes on the filter's outlet bottom to push the co2 downwards.

Cheers,
Mike