tim
Member
This thread is worth a read if you haven't already Sam.
Surface Film | UK Aquatic Plant Society
Surface Film | UK Aquatic Plant Society
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surface film
- Thread starter Samjpikey
- Start date
loads of threads on scum before now with clives input....
"I think you might be mixing up cause and effect. As mentioned before there is a relationship between the metabolic rate and the production of organic waste. If you feed the plants more CO2 then they will eject more waste products. So it's not surprising that more fats, oils and carbohydrates are ejected with increase metabolism due to increased consumption of CO2. The next step though is that with an increase in CO2 consumption there is a demand for more nutrients. The nutrient loading must match the CO2 loading. If the higher CO2 consumption is not matched by higher nutrient consumption, then the waste ejection is higher than normal.
CO2 metabolism is a much more complicated issue than nutrient consumption because of the Rubisco transport mechanism. You can lower the CO2, keep the same lighting and then you can observe an increase in the scum. If the CO2 was lowered only a small amount the scum may last only a few weeks as the plant adapts to the lowered CO2 level. If the new CO2 level is within the tolerance range for that lighting level then the plant can adapt. If the Lower CO2 level is too drastic for the lighting level then the plants continue to leach waste products into the water column. This then becomes a chronic issue and can lead to other CO2 deficiency symptoms.
If lighting level and nutrient levels are held constant, but if CO2 is increased, then this could lead to a demand for higher nutrient uptake. If this is not met then the excess ejection is caused by nutrient deficiency. Again, depending on how much more CO2 is being consumed, this determines the severity of the nutrient deficiency. If the increase in CO2 is mild to middling, then after a few weeks the plant has the ability to adapt by becoming more efficient at nutrient uptake. If the CO2 increase is significant then this may fall outside the range of the adaptability.
So it's very difficult to predict exactly how many ppm of this or that will result in excessive or normal ejection because of the range of adaptability and the degree of movement in all the associated variables. Not only are the environmental variables changing, but the plant themselves are changing. They increase in mass by growing, or decrease in mass by trimming or by loss of weight due to deficiency. So the same conditions may be present in two tanks but the symptoms may only appear in one tank due to lower bio-mass in one tank versus the other. Their energy reserves may be high or low which affects the speed and duration at which the symptoms appear or disappear. In order to get to the root of the problem one has to be able to control all variables in the equation, and that simply doesn't happen. People become impatient because we all want a quick fix. And that's why we draw these premature conclusions.
I use tons of CO2 and I don't have any of these issues. I can add more CO2 and the only thing that happens is more health, clearer water and more pearling. In my case I don't have to make any adjustments to nutrient levels because they are already unlimited.
This problem also has been reported in non-CO2 tanks. So the conclusion that this is caused strictly by CO2 can't be true unilaterally. This is an illusion and we simply haven't figured out the magicians trick.
In this shot I turned the filters off for a few hours to see how much oily film was actually present. There was very little, although you could see a thin film.
So generally, it really depends on where you are in terms of plant health and nutrition, not just "did I add more CO2", even though it might appear so at face value. Health and nutrition are always going to be linked to lighting intensity, flow/distribution, nutrient levels, bio-mass and so forth.
Surface film does not always deprive the tank of Oxygen. The film block gas transport across the air/water interface. Therefore, if the plants are producing Oxygen during the photoperiod, then less oxygen escapes to atmosphere. If the Oxygen level falls below atmospheric levels during the night then yes, the film does lower Oxygen ingress into the tank. The same goes for CO2.
It wouldn't be surprising at all that algal blooms in the tank are either accompanied by, or preceded by surface scum, because these are both health and nutrition related. In fact, typically one gets the film and then the algae. The film is a harbinger of doom because it's telling you that you have health issues.
Cheers,"
"I think you might be mixing up cause and effect. As mentioned before there is a relationship between the metabolic rate and the production of organic waste. If you feed the plants more CO2 then they will eject more waste products. So it's not surprising that more fats, oils and carbohydrates are ejected with increase metabolism due to increased consumption of CO2. The next step though is that with an increase in CO2 consumption there is a demand for more nutrients. The nutrient loading must match the CO2 loading. If the higher CO2 consumption is not matched by higher nutrient consumption, then the waste ejection is higher than normal.
CO2 metabolism is a much more complicated issue than nutrient consumption because of the Rubisco transport mechanism. You can lower the CO2, keep the same lighting and then you can observe an increase in the scum. If the CO2 was lowered only a small amount the scum may last only a few weeks as the plant adapts to the lowered CO2 level. If the new CO2 level is within the tolerance range for that lighting level then the plant can adapt. If the Lower CO2 level is too drastic for the lighting level then the plants continue to leach waste products into the water column. This then becomes a chronic issue and can lead to other CO2 deficiency symptoms.
If lighting level and nutrient levels are held constant, but if CO2 is increased, then this could lead to a demand for higher nutrient uptake. If this is not met then the excess ejection is caused by nutrient deficiency. Again, depending on how much more CO2 is being consumed, this determines the severity of the nutrient deficiency. If the increase in CO2 is mild to middling, then after a few weeks the plant has the ability to adapt by becoming more efficient at nutrient uptake. If the CO2 increase is significant then this may fall outside the range of the adaptability.
So it's very difficult to predict exactly how many ppm of this or that will result in excessive or normal ejection because of the range of adaptability and the degree of movement in all the associated variables. Not only are the environmental variables changing, but the plant themselves are changing. They increase in mass by growing, or decrease in mass by trimming or by loss of weight due to deficiency. So the same conditions may be present in two tanks but the symptoms may only appear in one tank due to lower bio-mass in one tank versus the other. Their energy reserves may be high or low which affects the speed and duration at which the symptoms appear or disappear. In order to get to the root of the problem one has to be able to control all variables in the equation, and that simply doesn't happen. People become impatient because we all want a quick fix. And that's why we draw these premature conclusions.
I use tons of CO2 and I don't have any of these issues. I can add more CO2 and the only thing that happens is more health, clearer water and more pearling. In my case I don't have to make any adjustments to nutrient levels because they are already unlimited.
This problem also has been reported in non-CO2 tanks. So the conclusion that this is caused strictly by CO2 can't be true unilaterally. This is an illusion and we simply haven't figured out the magicians trick.
In this shot I turned the filters off for a few hours to see how much oily film was actually present. There was very little, although you could see a thin film.
So generally, it really depends on where you are in terms of plant health and nutrition, not just "did I add more CO2", even though it might appear so at face value. Health and nutrition are always going to be linked to lighting intensity, flow/distribution, nutrient levels, bio-mass and so forth.
Surface film does not always deprive the tank of Oxygen. The film block gas transport across the air/water interface. Therefore, if the plants are producing Oxygen during the photoperiod, then less oxygen escapes to atmosphere. If the Oxygen level falls below atmospheric levels during the night then yes, the film does lower Oxygen ingress into the tank. The same goes for CO2.
It wouldn't be surprising at all that algal blooms in the tank are either accompanied by, or preceded by surface scum, because these are both health and nutrition related. In fact, typically one gets the film and then the algae. The film is a harbinger of doom because it's telling you that you have health issues.
Cheers,"
Ok guys ,
Got some great news . Last night I dropped the temp of the tank down from 25c to 21c (co2 saturates the water better in cooler temp), I'm always trying to find ways of getting the most out of the co2 supply ( ain't we all?)
Just got home to find almost NO surface skum,
No bubbles/foam at all , it has almost completely cleared up.
So could it be the warmer water played its part?
I'm also getting a better reading of a ph drop In relation to the co2 injection- By .2 - could it have been a sign of co2 deficiency ?
??cheers
Sent from my mobile telecommunications device
Got some great news . Last night I dropped the temp of the tank down from 25c to 21c (co2 saturates the water better in cooler temp), I'm always trying to find ways of getting the most out of the co2 supply ( ain't we all?)
Just got home to find almost NO surface skum,
No bubbles/foam at all , it has almost completely cleared up.
So could it be the warmer water played its part?
I'm also getting a better reading of a ph drop In relation to the co2 injection- By .2 - could it have been a sign of co2 deficiency ?
??cheers
Sent from my mobile telecommunications device
Yo-han
Member
A lower temp will make your plants metabolism slower and thus producing less organic waste
Rob P
Member
- Joined
- 13 Oct 2013
- Messages
- 785
I've had really minor scum recently, it's only appeared in the last week and is very minor. The only things that have changed are a significant increase in plant growth since putting on a bigger filter and inline diffuser 2 weeks ago. Also put a couple of new plants in that are adapting to life under water.
Ironically, I ordered an Eheim 350 skim yesterday but last night I tweaked my spray bar to provide a little more surface agitation (was already a fair bit) and surface looks crystal this morning, doh!
Ironically, I ordered an Eheim 350 skim yesterday but last night I tweaked my spray bar to provide a little more surface agitation (was already a fair bit) and surface looks crystal this morning, doh!
Rob P
Member
- Joined
- 13 Oct 2013
- Messages
- 785
Yes I kind of look at it that way, but i'm also expecting a <cough> twinstar <cough> at some point and i'm sure i've read these help keep the suface clear as well. Perhaps a bit too impulsive!
My eheim came today , was waiting patiently at my next door neighbors house ,
The surface film was bk as well since I've fed the fish this morning so the food I'm using is definitely contributing to the film .
I must say the eheim skim is a BLODDY wonderful peice of kit wow ....very small and Cleared the tanks surface within minutes
Money well spent and just finished work for 16 days happy happy joy joy
Sent from my mobile telecommunications device
The surface film was bk as well since I've fed the fish this morning so the food I'm using is definitely contributing to the film .
I must say the eheim skim is a BLODDY wonderful peice of kit
wow ....very small and Cleared the tanks surface within minutes Money well spent and just finished work for 16 days
happy happy joy joy Sent from my mobile telecommunications device
steveno
Member
Yes I kind of look at it that way, but i'm also expecting a <cough> twinstar <cough> at some point and i'm sure i've read these help keep the suface clear as well. Perhaps a bit too impulsive!
Sorry to break to you rob, twinstar installed still have surface scum, I recently purchase a glass inlet that also has skimmer. To deal with oily film from fish food.
steveno
Member
Happy to hear that you've sort your surface scum...sam
It probably was a number of things ,
Funny how it cleared up after dropping the temp but came bk within 12 hours of adding some food (probably out of date )
Nevertheless the ehiem skim is awesome
The surface is the cleanest it been for a long time
Now I know I can get rid of it I can do some tests to see what brings back the film etc
Sent from my mobile telecommunications device
Funny how it cleared up after dropping the temp but came bk within 12 hours of adding some food (probably out of date )
Nevertheless the ehiem skim is awesome
The surface is the cleanest it been for a long time
Now I know I can get rid of it I can do some tests to see what brings back the film etc
Sent from my mobile telecommunications device
Rob P
Member
- Joined
- 13 Oct 2013
- Messages
- 785
Yo-han
Member
