Summer's effect on plants

[scottward]

Hi. Here in Australia it is starting to warm up, eventually summer will hit and 30 degree days will be the norm.

Before the weather gets hot (still in the mid 20's at the moment), I want to arm myself with some knowledge...

I have been really focussing on CO2 lately and can see that it is the single area that I should have spent my time on earlier on!

As the water temperature in my tank rises, I understand that the plants metabolism will start to increase; their demand for CO2 and nutrients will rise? Correct?

So, over summer I can leave the lighting alone. And I can also leave the nutrients alone as I am dosing EI anyway.

So, over Summer, all I should really have to do is increase the CO2 going into my tank? And the reason for this is simply because CO2 solubility is a lot (?) lower as the water temperature rises and the CO2 will degass more easily?

Going from say, 25 degrees to say 30 degrees celcius, should I need a dramatic increase in the CO2 bubble rate or is it really not as 'bad' as I think?

I should be able to maintain healthy lush growth in 30 degree temps shouldn't I? Discus tanks are maintained at this temperature anyway aren't they?

Scott.

 

[Tom Barr]

CO2 and moire water changes are the items when the temps are higher.
It's typically 35-40C here where I live, a bit like the Western deserts for you, and in places just as hot if not more so (Death Valley comes to mind).

The demands for CO2 are roughly 30-50% higher at say 30C vs 20C for plants.
That's a huge amount if you are use to adding 3 bps and now need 5-6bps.
Few account for this.

The other issue is that O2 is also lower, not but nearly as much, perhaps 0.5 ppm (I'm too lazy to get my temp O2 chart out).

Still, it's a compound effect on fish, more CO2, less O2.
Fish, bacteria etc all need more O2 to keep up with their increased respiration rates as well.

Plants will grow faster and produce more O2 however.
So there is some counter balance. This assume that the plants have enough light and CO2 for this temp also to respond to temp increases independent of light.

Fans are a popular cooling method.
The folks in Singapore often have issues and like shrimps, mosses... so cooling is a priority. Fans seem to do well there.


Regards,
Tom Barr

 

[Gbark]

please excuse my naivety, but surely your tank water temp stays constant all year? Why would it increase with outside tempature, unless it is outside?

Maybe a stupid idea, but if you do need to cool your tank water, and you don't want the expense of a vapour chill unit. I would suggest buying a small/mini fridge from your local DIY store (no more than £15 in the uk). Coil up a large amount of plastic tubing inside, and then pump your tank water through it at a slow rate. Should be sufficant to drop the temp by a couple of degrees.

 

[Tom Barr]

In Oz, as well as CA, USA(and many other locations), the summer temps can climb pretty high(30-35C for aquariums, air temps 40-45C), many do not have chillers or air conditioners(AC) to keep their homes cool, we use fans, or simply save on the $$. Some have well insulated homes and the cost and temp rise is not as bad as others.

Fans work pretty good where it's a dry heat.
But in central Florida, forget it. Add gnawing insects, and it's really trouble.
AC is the only thing that will keep you comfy.

Northern Oz gets godawful, humid + hot.
Bad combination.

Some just get use to it.
This is where many nice aquatics come from too
In CA, the dry heat cools off good at night, but in humid places, it sticks around, makes sleeping difficult.

Regards,
Tom Barr

 

[scottward]

Hi Tom and Gbark, thanks for the replies.

CO2 and moire water changes are the items when the temps are higher.
It's typically 35-40C here where I live, a bit like the Western deserts for you, and in places just as hot if not more so (Death Valley comes to mind).

The demands for CO2 are roughly 30-50% higher at say 30C vs 20C for plants.
That's a huge amount if you are use to adding 3 bps and now need 5-6bps.
Few account for this.

Is this 30-50% increase imposed purely by the plants needing more due to their higher metabolism, or does the reduce solubility of CO2 in warmer water play a large part?

At the moment my tank is around the mid-20's. Once summer hits properly, the water temperature will get up around the mid-30's. Ok, so a 10 degree change in temp can require 30-50% more CO2. At the moment I am pumping in somewhere around 10-15 bps (hard to count this fast).

As per your usual advice Tom, I guess I am just going to have to use my eyes and watch the plants as the water warms up.

If I were to make no changes to the CO2 bubble rate, I would expect that the plants would start to loose their lush green colouration (start to yellow a bit), their growth would suffer, and, would I be right in thinking that I might start to see some BBA as the CO2 level starts to wane???

I guess the best strategy would be for me to simply turn the CO2 up just a little bit each day once the plants start looking a little off-colour? Or would I be better of making a small change and waiting a week for Rubisco to adjust before touching the needle value again?

The other issue is that O2 is also lower, not but nearly as much, perhaps 0.5 ppm (I'm too lazy to get my temp O2 chart out).

Still, it's a compound effect on fish, more CO2, less O2.
Fish, bacteria etc all need more O2 to keep up with their increased respiration rates as well.

Plants will grow faster and produce more O2 however.
So there is some counter balance.

Ah yes, I knew about this one. One year it got so hot that some of my smaller, overpopulated tanks sufferred many deaths due to O2 shortage.

My large planted tank is somewhat understocked, so I should be ok.

I live in Brisbane. There are much worse parts of Oz than here, they must go through a lot of CO2 in say, Weipa. ;-)

This assume that the plants have enough light and CO2 for this temp also to respond to temp increases independent of light.

I don't quite understand this bit Tom, but it sounds important, so I better make sure I get it. Are you saying here that, at a given temperature of water, a certain light level might be adequate, but, if the temperature of the water rises, the light level might become insufficient? I can understand completely how the CO2 level might not be enough anymore as the water temp rises (higher demand due to increased metobolic rate of plants plus lower solubility), but the lighting??

Fans are a popular cooling method.
The folks in Singapore often have issues and like shrimps, mosses... so cooling is a priority. Fans seem to do well there.

We have insulation in our roof and ceiling fans, but no air con, dedicated aquarium fans or a chiller.

Provided I can get the CO2 level high enough, and assuming I've misunderstood the bit about light above, there is no reason why the plants shouldn't do well in the warm water? i.e. if the CO2 level was fine, lighting was fine, nutrient levels fine, should the average aquarium plant do perfectly fine in very warm water (up to a point of course).

Thanks again,
Scott.

 

[Tom Barr]

I'll be in Brisbane next month for a talk on plants.

The idea about temp is more related to metabolism and Q10's.

BIOG 1105-1106 | Introductory Biology, Individualized Instruction

http://en.wikipedia.org/wiki/Q10_(temperature_coefficient)

SpringerLink - Journal Article

Biomass effects and temp bichem processes:
http://www.sccs.swarthmore.edu/users/08/bblonder/phys120/docs/gillooly.pdf

Effects on Plant carbohydrates(respiration):
Effects of low temperature on the respiratory meta...[Symp Soc Exp Biol. 1988] - PubMed Result

Regards,
Tom Barr

 

[Tom Barr]

If you have a non CO2 aquarium, and increase the temp from say 20C to 30C, then the effects on CO2 stability are pretty bad

So temp has a role for CO2 stability as well, this is a rather obvious aspect, but I've never once seen a single post on line about algae and CO2 and the temp relationship.

Everyone seems to think that adding CO2 is all there is to it.
..........that CO2 in aquarium is simple and is not complicated or influenced by many other factors.

It's linked to nutrients strongly, it's linked to temp, light etc. everything........


Regards,
Tom Barr

 

[scottward]

Hi Tom,

Thanks for the further info and the links....I have some reading to do.

After I've had a read, I may need your help to distill the information a bit.

Tell me more about your trip to Brisbane....where are you giving the talk and can anybody come along to it? What will talk specifically be about (aquarium plants?)

Scott.

 

[Tom Barr]

The aquarium club is having it and a demo by me.
More just a simple how to demo, with lots fo sp[ecific questions and hopefully answers

Contact Leo for more info.
3 weeks from now

ANGFA Forums :: Index

Regards,
tom barr

 

[scottward]

Hi Tom,

Thanks for the info about the presentation, I would probably enjoy something like that but don't think I would have the time to attend.

Regarding the effect of temp on CO2, I had a look at the articles that you hyperlinked. I get the general idea, but a lot of the detail was a bit over my head.

I will create a brand new thread to discuss this in more detail, in simpler 'hobbyist' terms. I have a few questions.

Scott.

 

[Tom Barr]

Hi Tom,

Thanks for the info about the presentation, I would probably enjoy something like that but don't think I would have the time to attend.

Regarding the effect of temp on CO2, I had a look at the articles that you hyperlinked. I get the general idea, but a lot of the detail was a bit over my head.

I will create a brand new thread to discuss this in more detail, in simpler 'hobbyist' terms. I have a few questions.

Scott.

The general idea is fine.
Also, that it is not just baloney someone pulled out of their hat..........

There is a meeting in Brisbane on Firday after that main Oz meeting in Sydney.
I'll be doing a demo, a LFS will be supplying the materials etc

Regards,
Tom Barr