too much light

[chris58b]

Hi,
I have a 25 UK gal tank ( L30" x H18" x W12" ) that is heavily planted .I am ei dosing and injecting co2 at 4 bps with good surface agitation. My co2 is on 2 hr's before lights on and dc's are lime green at lights on. Filter is a tetratec 700 with 2 circulation pumps ( hydro pico eco mag 650's). I would consider my co2 levels and flow to be good.
I have 3 x 25 watt t 8 bulbs ( 1 arcadia original tropical and 2 arcadia freshwater) . would you consider this too much light?
The reason for asking is I am getting a bit of short hair algae and a bit of bba. I thought bba was due to poor flow and insufficient co2 but I have it growing in high flow areas as well a slower flow areas and co2 at 4 bps!. Also I thought that hair algae was due to an imbalance of light and co2( perhaps too much light). what do you think I should do to resolve the algae issues?

 

[chris58b]

I forgot to say that my lights and co2 are on for 7 hrs .

 

[chris58b]

Oh, and a 60% water change per week. Kh 4. GH 6. PH 6.2-7.1 Nitrite <0.3 mg/l. Moderate fish numbers.

 

[foxfish]

You dont say how you are dissolving the C02 or how it is distributed but yes - to much light or to little C02 for the lights being used.
A picture paints a thousand words though......

 

[chris58b]

Hi foxfish,
I knew I would forget something. The co2 is disolved via an inline reactor( the co2 supermarket one) and fed back into the tank via the return pipe. The co2 enriched water is then blown around the tank by the 2 circulation pumps.
The plants all pearl and all grow well without any obvious deficiencies.
I will try to post a pic of the tank once I have sussed out how to do it.

 

[ceg4048]

Just because plants are pearling it does not mean they are in top health. You need to increase the injection rate if you have the headroom for the fish in the tank. The fact that there is BBA and hair algae automatically means that there is a CO2 deficiency.

Cheers,

 

[chris58b]

here is a pic of the tank

I should add that the tank has been running for 18 months but this scape ( my first planted one) is about 8 weeks old. The bba started when i was increasing the co2 levels to find my optimum level. Will it recede whith good co2. Also, The Hair algae does seem to continue to appear

 

[chris58b]

can anyone see my pic, i cant. which is the best way to insert an image?

 

[chris58b]

Just because plants are pearling it does not mean they are in top health. You need to increase the injection rate if you have the headroom for the fish in the tank. The fact that there is BBA and hair algae automatically means that there is a CO2 deficiency.

Cheers,

are you saying that 75 watt of T8 is ok for my tank and that i should match the co2 levels to my light?
I'm not sure i can push my co2 much more without affecting the fish.
Is over 4 bps dissolved in a reactor the norm for a 25 gal planted tank?

 

[chris58b]

 

[chris58b]

 

[chris58b]

 

[ceg4048]

Hi,
Sweet looking tank, but sadly, yes, this is symptomatic of a CO2 deficiency. So, the only way to fix it is to either lower the CO2 demand or to increase the CO2. Lowering the light intensity reduces the uptake demand and adding Excel type products or more CO2 raises the availability.

You might also be able to use more flow to distribute as well. Textured backgrounds tend to disrupt flow. AS the plants grow there is more mass to feed.

Cheers,

 

[chris58b]

Hi,
Sweet looking tank, but sadly, yes, this is symptomatic of a CO2 deficiency. So, the only way to fix it is to either lower the CO2 demand or to increase the CO2. Lowering the light intensity reduces the uptake demand and adding Excel type products or more CO2 raises the availability.

You might also be able to use more flow to distribute as well. Textured backgrounds tend to disrupt flow. AS the plants grow there is more mass to feed.

Cheers,

Thanks for your advice, I really do value your opinion. I think I will up the co2 first and monitor the fish. Should it stress the fish I will return co2 back to 4bps and lower light instead.

Should the algae recede under the right conditions or do I need to remove it and watch for new growth?

 

[foxfish]

I would look at flow too, it is amazing how delicate the balance can be sometimes!
It looks like you have a powerheasd pointing at the surface, perhaps angle that down a bit, also, you could start dosing liquid carbon.
In many cases a spray bar will help flow if you have a powerful enough filter.

 

[chris58b]

Hi foxfish,
The top circulation pump primeraly agitates the surface to maintain the oxygen levels whilst i'm injecting a lot of co2. There is a second circulation pump lower down that helps push the co2 around. If I watch the small co2 bubbles they do appear to go all around the tank. Nowhere in the tank seems to be short of co2 bubble movement. Flow wise there are 2 x 650 ltr per hr circulation pumps and the tetratec 700 which put out about 350 ltr per hr realistically.
I have now angled the top powerhead down a bit.

 

[ceg4048]

The top circulation pump primeraly agitates the surface to maintain the oxygen levels whilst i'm injecting a lot of co2.

This is not really a good idea. I think folks don't realize that adding CO2 causes the plants to deliver higher concentrations of Oxygen in the tank than is possible via aeration, so doing this not only dissipates CO2 to lower the oxygen production, but it also out-gases the oxygen that the plants are producing. This is a very bad policy. It's counterproductive and causes greater toxic effects.

Cheers,

 

[Simanas]

This is not really a good idea. I think folks don't realize that adding CO2 causes the plants to deliver higher concentrations of Oxygen in the tank than is possible via aeration, so doing this not only dissipates CO2 to lower the oxygen production, but it also out-gases the oxygen that the plants are producing. This is a very bad policy. It's counterproductive and causes greater toxic effects.

Cheers,

Am I mistaking something, or you have always suggested good surface agitation? "point spray bars upward..."

 

[foxfish]

I think there is a difference between having a spraybar pointing slightly up toward the front glass & a power head directed at the surface.
Surface agertasion & surface movement are different aspects in my view.

 

[dw1305]

Hi all,

are you saying that 75 watt of T8 is ok for my tank and that i should match the co2 levels to my light? I'm not sure i can push my co2 much more without affecting the fish.

I think the plant health looks pretty good, just keep things the same and I wouldn't worry about the small amount of green algae or BBA. I know they aren't to every-ones taste, but Red Ramshorn snails are effective at removing BBA sporelings from hard surfaces.

The "problem" is that if you have condition suitable for mosses, ferns and higher plants you also have conditions suitable for all other photosynthetic organisms - "algae". This is particularly true for the green algae. From "The Tree of Life: Green Plants" <Green plants>

Green plants as defined here includes a broad assemblage of photosynthetic organisms that all contain chlorophylls a and b, store their photosynthetic products as starch inside the double-membrane-bounded chloroplasts in which it is produced, and have cell walls made of cellulose (Raven et al., 1992). In this group are several thousand species of what are classically considered green algae, plus several hundred thousand land plants.

I'll leave CO2 to the others, I'm, to say the least, a CO2 agnostic, and I would worry about long term sub-lethal effects, as well as the ever present problem of a CO2 dump asphyxiating all your fish.

cheers Darrel