# Water temperature, O2/CO2 levels, plant growth in low tech



## Maryland Guppy (Dec 6, 2014)

I recently moved from a religious 72 to 75 degrees one month ago.
Increase in plant growth has occurred.
Some plants grow less, grateful for two species I trimmed too often.
Choosing not to go warmer due to CO2 loss.
I use no surface agitation what so ever, too much degassing of CO2.
All filter discharge is brought back underwater for a reason.

All gases are more difficult to hold in warmer water.

O2 production via pearling and substrate release is common for me.
Not extreme but little bubbles everywhere every day.


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## Oso Polar (Apr 22, 2015)

It depends on the plant species, some do better in warmer water, but overall it is definitely harder to grow plants at higher temperature, especially without CO2 injection.


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## jcmv4792 (Jul 15, 2015)

Maryland Guppy said:


> I use no surface agitation what so ever, too much degassing of CO2.
> All filter discharge is brought back underwater for a reason.
> 
> All gases are more difficult to hold in warmer water.


Some people here have said that with low tech, surface agitation can actually help bring in atmospheric Co2 into the water, as opposed to high tech where too much surface agitation would just degass the "extra" co2. What are your thoughts on this?

For reference:

http://www.plantedtank.net/forums/showthread.php?t=914713&page=2


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## Xiaozhuang (Feb 15, 2012)

Plants will grow faster in warmer waters; with increased demands for O2, CO2, nutrients . Plant metabolism is roughly doubled at 82f vs 70f. Same for bacteria etc as well. 

From growing multiple tanks in warmer temps, (80-86), I'd say temperature matters more for high-tech tanks. Many people will face balance issues, or O2/CO2 issues, stem elongation, algae at higher temps. 

Also partly because most of the species one chooses to grow in low tech tanks are more resilient in general. I'd say some surface agitation is useful, if only for the increased O2 (bacteria processes consume this too). You can browse through my series of low tech nanos - high temps (80-86f) isn't really an issue


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## Maryland Guppy (Dec 6, 2014)

jcmv4792 said:


> Some people here have said that with low tech, surface agitation can actually help bring in atmospheric Co2 into the water, as opposed to high tech where too much surface agitation would just degass the "extra" co2. What are your thoughts on this?


My wife's two guppy tanks are no-tech with lots of surface breaking.
Evaporation is an issue so HOB's break the surface always.
It seems to work well in this case.
Constant jungle with lots of trimming required.
Temps in these 2-20G are @ 76 degrees.


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## jaggerpowers (Jun 28, 2014)

Hi am new to the planted tank, was wondering if i can use the 13 cubic ft pony tank for co2??


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## BBradbury (Nov 8, 2010)

*Aquatic Plants in Warmer Water*

Hello jc...

If you keep a low tech tank with a couple of watts of light for every gallon of tank volume, this is enough to grow most of the plants you get from the pet store. They don't need more CO2 than what's in the air that gets mixed in with O2 from the filter system moving the surface water. These plants are tropical and require long hours of daylight. So, keep your tank lights on roughly 12 hours a day. 80 to 82 degrees is the highest. 78 is about right for the plants.

The low light plants are undemanding and don't need special fertilizers. Just keep a good fish load and feed a balanced diet of flakes, freeze dried and frozen foods.

The most important requirement for your plants is a steady source of minerals. They don't get this unless you change out half or more of the tank water weekly. Water that's constantly run through a filter loses minerals within a few days. The longer water stays in the tank the less it's able to support anything that lives in it.

B


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## Hoppy (Dec 24, 2005)

BBradbury said:


> Hello jc...
> Water that's constantly run through a filter loses minerals within a few days. The longer water stays in the tank the less it's able to support anything that lives in it.
> 
> B


How does a filter remove ions from the water? Plants use both cations and anions, and all of their nutrients have to be in that form for the plants to use them. Many people don't do water changes except at several month increments, and, as long as they use low light intensity, they get good plant growth. I think that disproves the statement above. I agree that big water changes are usually desirable, but that doesn't mean they are essential.


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## jcmv4792 (Jul 15, 2015)

Hoppy said:


> How does a filter remove ions from the water? Plants use both cations and anions, and all of their nutrients have to be in that form for the plants to use them. Many people don't do water changes except at several month increments, and, as long as they use low light intensity, they get good plant growth. I think that disproves the statement above. I agree that big water changes are usually desirable, but that doesn't mean they are essential.





BBradbury said:


> Hello jc...
> 
> If you keep a low tech tank with a couple of watts of light for every gallon of tank volume, this is enough to grow most of the plants you get from the pet store. They don't need more CO2 than what's in the air that gets mixed in with O2 from the filter system moving the surface water. These plants are tropical and require long hours of daylight. So, keep your tank lights on roughly 12 hours a day. 80 to 82 degrees is the highest. 78 is about right for the plants.
> 
> ...


There's one thing I don't quite get with the "water changes only a couple months" concept. I use to assume that plants and bacteria would break down all of the waste from the inhabitants(fish, shrimp, snails..etc), however i've also read that no matter how heavily planted your tank is, there are still things in fish waste that plants do not consume/break down..hence the need for weekly water changes. Any input on this?


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## strangewaters (May 13, 2015)

Water changes are also good to keep the temp down in the tank since its so hot right now.

Sent from my LG-D851 using Tapatalk


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## Hoppy (Dec 24, 2005)

jcmv4792 said:


> There's one thing I don't quite get with the "water changes only a couple months" concept. I use to assume that plants and bacteria would break down all of the waste from the inhabitants(fish, shrimp, snails..etc), however i've also read that no matter how heavily planted your tank is, there are still things in fish waste that plants do not consume/break down..hence the need for weekly water changes. Any input on this?


Weekly 50% water changes "reset" the water parameters, so nothing that is accumulating in the water can get higher than 2X the weekly addition of that substance. When you are dosing a bit too much of all of the nutrients on purpose, that weekly water change is very important. But, with low light tanks, you are probably not dosing anything to excess, so the water change isn't as important. Along with almost all water changes, using tap water, comes a surge in CO2, too. (The water has been under pressure, and cold, so it will hold more dissolved gases of all kinds in solution than when it is warm and at atmospheric pressure. A lot of well water is very high in CO2 naturally, and some water suppliers use CO2 to lower what would otherwise be a very high pH.) That surge in dissolved CO2, followed by outgassing down to low CO2, can trigger a BBA invasion, even in low light tanks. That is one reason for not doing weekly water changes in a low light tank. Many people have no problems with doing big water changes only every few months, so it certainly does work.


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## jcmv4792 (Jul 15, 2015)

Hoppy said:


> Weekly 50% water changes "reset" the water parameters, so nothing that is accumulating in the water can get higher than 2X the weekly addition of that substance. When you are dosing a bit too much of all of the nutrients on purpose, that weekly water change is very important. But, with low light tanks, you are probably not dosing anything to excess, so the water change isn't as important. Along with almost all water changes, using tap water, comes a surge in CO2, too. (The water has been under pressure, and cold, so it will hold more dissolved gases of all kinds in solution than when it is warm and at atmospheric pressure. A lot of well water is very high in CO2 naturally, and some water suppliers use CO2 to lower what would otherwise be a very high pH.) That surge in dissolved CO2, followed by outgassing down to low CO2, can trigger a BBA invasion, even in low light tanks. That is one reason for not doing weekly water changes in a low light tank. Many people have no problems with doing big water changes only every few months, so it certainly does work.


Thanks. Would you say this still applies to low-tech tanks with lots of HOB filtration(lots of surface agitation), and those who do water changes at night?

I'm wondering if a water change at night would not "confuse" the plants internal mechanisms since they release co2 then, and if the addition of lots of hob filtration would "degass" that surge of co2 overnight. If not, how long does it usually take co2 to degass out of water(with surface agitation)?


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