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what makes them grow?


killifan

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I'm new to tropicals and am learning lots here! Mt plants just aren't growing though. Don't know their names, the smallleafed ones are going pale and some are growing a fluffy dark substance on them as are the 2 little grass plants, but the broader leafed one isn't. How do you feed plants in a tank? Should I leave the light on all day when I'm at work, (the tank gets light but not direct sun).

Killifan

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What do the plants have for nutrition, are they planted into a good substrate (peat or laterite) or just into plain gravel. They will be getting some food from the fish wastes but not exactly the right stuff for good growth, if needed a plant food for tropical tanks will give them a good boost.

Agree with Ira about the lights, not enough light then no growth.

The fluffy dark stuff is probably an algae, keep the water clean and feed the plants and this may slow the algae growth

Have a look here the articles show photos of some of the more common types of algae and how to control.

http://www.thekrib.com/Plants/Algae/

Mark

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What do the plants have for nutrition, are they planted into a good substrate (peat or laterite) or just into plain gravel. They will be getting some food from the fish wastes but not exactly the right stuff for good growth, if needed a plant food for tropical tanks will give them a good boost.

Mark

Plants are just in a gravel. What is laterite?

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Hi Killifan,

Welcome to the forum.

Plants need the following to grow and survive:

To Eat:- Nitrates, Potassum, Phosphates, various trace elements

To Breath:- CO2

To Energise:- Light

If any one of these is increased then the other 2 also have to be increased to meet the plants demands. The more of these 3 supplied the faster the plant will grow. Of course a limit is reached and different plant species need different amounts. Any excess that the plants don't use up will encourage algae to grow.

Depending on the type of plant, the majority of the food is obtained from either the substrate or from the water. Most common plants obtain thier nutrients from both. Laterate is an iron based clay that is commonly used as a layer under the gravel since aquariums normally lack iron for plant use. Other mediums can be used or fertiliser sticks can be poked under the gravel. I am even using Kitty Litter (not used! :lol: ). For fertilising the water a brand name aquarium fertiliser from your LFS is best to start with.

Research as much as possible before adding anything to the tank otherwise you could end up with a algae bloom or sick fish. A good site to look at is Pauls:

http://paul.aaquaria.com/home/Home.htm

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As has been mentioned plants require a number of things to grow. The most common reason I've come across for poor plant growth is insufficient light.

As Ira's mentioned the lights should ideally be on 12-14 hours a day. There are also different rules of thumb about how many watts of light per litre. I'm inclined to generalise and say for a 'normal' depth tank you'd want two flourescent tubes (I suspect people will comment on this and say that you should have more - but from my own tanks having 2 tubes gives me adequate plant growth - ie enough that I can hock off cuttings every now and then but not need a machette).

Also light quality from fluorescent tubes deteriorates with time, so the tube should be replaced every 6-12 months. Yuo mention that it's second hand so it's possible the tube hasn't been replaced in years.

Replacing tubes can get expensive if you've got a number of tanks and are getting the 'proper' tubes from aquarium shops. One of our club meetings discussed this and the people who are into growing aquatic plants recommended that you just go to an electrical supply house (eg MasterTrade, Ideal Electrical etc) and get the appropriate length #86 tubes. The 86 has to do with the light spectrum and colour rendering produced by the tube. Apparently this code is the best one for plant growth (Warren probably has a better idea) - though I've only ever managed to find 86.5 and ahve had no problems so far.

Just an indication of price - I recently replace two 5' tubes and two 4' tubes - cost be $40 total.

Once you've got the lighting sorted out then you can start worrying about fertiliser, CO2 etc. I'd personally wait a while after sorting the ligths to see what response you've got from that change.

Whats laterite? - Laterite is an iron rich clay that people will often have beneath a layer of gravel. The reason is that one of the more common deficiencies in aquarium plants is iron.

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Is it a dual light? So you've got 20 watts on about a 100 liter tank. That's quite low light, but is ok for low light plants. But they won't grow very fast.

yes,its a 20 watt light but defintely npot a 100 litre tank! measurements are 79x29x25 which according to my calvulations works out at 54.3 litres.

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It's not really that sunlight makes algae grow and flourescent doesn't, it's more that sunlight is a LOT brighter than the tank lights for the most part, not getting into things like different light spectrums and stuff. I haven't been able to find out what kind of lighting would be needed to match it, other than some idiot insisting that the sun is 10,000 times brighter than a 250 watt metal halide so you'd need 2,500,000 watts of flourescent lighting to match it...Ooops, tangent. Anyway, the sun is just a lot brighter than the tank lights so you end up with the algae outcompeting the plants sometimes. If you had good plants and constant sunlight though the same things to combat algae would work as with lower light.

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if you have laterite or some other substrate under the gravel, what happens to it when you 'vacuum' the gravel?

Vacuuming isn't so important in a heavily planted tank. When you do you just lightly vacuum so you don't distrupt the gravel. The laterite or peat or other substrate is covered by at least 1" of gravel so you won't have to worry about sucking it up.

what is it about natural light that makes algae grow and fluorescent lighting doesn't?

Fluorescent light does make algae grow. The difference between the 2 is the strength of natural light and the difference in the spectrum produced. You will need some very powerfull artificial lights to equal the strength of sunlight.

Algae will only grow if the the 3 components of plant growth (light, various nutrients and CO2) are not in balance. High order plants are more competitive in using these components when they are in balance thus starving the algae. Algae can make do with a larger imbalance. A common solution to an algae problem is not to decrease light, fertiliser or Co2 but to actually increase one or the other until the algae disapears. Of course you need enough plants in the tank to use up these components before the algae can.

Finding the correct balance for your tank and setup is a matter of trial and error (and research).

Rob

Also light quality from fluorescent tubes deteriorates with time, so the tube should be replaced every 6-12 months

Thanks for the reminder a years coming up for mine.

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High order plants are more competitive in using these components when they are in balance thus starving the algae.

What do you mean by "higher order plants"?

Also is there some kind of a ratio for size of pond to amount of plants? I'm thinking specifically of my outdoor pond for which I can find no cold water algae eater.

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