Anubias are not floating plants and should be tied or glued to a rock or some other surface. A plant substrate does nothing for Anubias or Java Fern
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TURNING LIGHTS ON AND OFF
Stress from tank lights coming on when the room is dark can be an issue. Fish don't have eyelids and don't tolerate going from complete dark to bright light (or vice versa) instantly.
In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.
At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.
Try to have the lights on at the same time each day. Use a timer if possible.
If the light unit is programmable, have it on a low setting for the first 30-60 minutes and increase the brightness over time. Do the opposite in the evening and gradually reduce the light for the last 30-60 minutes before lights out.
If you don't have live plants in the tank, you only need the light on for a few hours in the evening. You might turn them on at 4 or 5pm and off at 9pm.
If you do have live plants in the tank, you can have the lights on for 8-16 hours a day but the fish and plants need 8 hours of darkness to rest. Most people with live plants in their aquarium will have the lights on for 8-12 hours a day.
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LIGHTING TIMES
Most aquarium plants like a bit of light and if you only have the light on for a couple of hours a day, they struggle. If the light doesn't have a high enough wattage they also struggle. Try having the tank lights on for 10-12 hours a day.
If you get lots of green algae then reduce the light by an hour a day and monitor the algae over the next 2 weeks.
If you don't get any green algae on the glass then increase the lighting period by an hour and monitor it.
If you get a small amount of algae then the lighting time is about right.
Some plants will close their leaves up when they have had sufficient light. Ambulia, Hygrophilas and a few others close their top set of leaves first, then the next set and so on down the stem. When you see this happening, wait an hour after the leaves have closed up against the stem and then turn lights off.
Plant lights should have equal amount of red and blue light and a bit less green light.
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TRUE AQUATIC VS MARSH/ TERRESTRIAL PLANTS
Lots of plants are sold as aquarium plants and most are marsh plants that do really well when their roots are in water and the rest of the plant is above water. Some marsh plants will do well underwater too.
Hair grass is not a true aquatic plant, neither is Anubias.
Some common marsh plants include Amazon sword plants, Cryptocorynes, Hygrophila sp, Rotala sp, Ludwigia sp, Bacopa sp. These plant do reasonably well underwater.
True aquatic plants include Ambulia, Cabomba, Hornwort, Elodia, Hydrilla and Vallis.
The main difference between marsh plants and true aquatic plants is the stem. True aquatics have a soft flexible stem with air bubbles in it. These bubbles help the plant float and remain buoyant in the water column.
Marsh plants have a rigid stem and these plants can remain standing upright when removed from water. Whereas true aquatic plants will fall over/ collapse when removed from water.
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IRON BASED PLANT FERTILISER
If you add an iron based aquarium plant fertiliser, it will help most aquarium plants do well. An iron based fertiliser is not just iron, it contains other nutrients as well, but the main ingredient is iron. The liquid iron based aquarium plant fertilisers tend to be better than the tablet forms, although you can push the tablets under the roots of plants and that works well.
You use an iron (Fe) test kit to monitor iron levels and keep them at 1mg/l (1ppm).
I used Sera Florena liquid plant fertiliser but there are other brands too.
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CARBON DIOXIDE (CO2)
There is no point adding carbon dioxide (CO2) until you have the lights and nutrients worked out. Even then you don't need CO2 unless the tank is completely full of plants and only has a few small fish in or no fish in it.
There are no natural waterways anywhere around the world that have supplemental CO2 added to them to make aquatic plants grow. People add CO2 to aquariums to help some marsh/ terrestrial plants grow underwater. These plants should not be grown in aquariums and the fact they need to add CO2 (as well as huge amounts of fertiliser and light) just to keep them alive is a clear indication they shouldn't be kept underwater.
In an average aquarium, there is a constant source of carbon dioxide produced all day and night by the fish, and the bacteria in the gravel and filter. More CO2 gets into the aquarium from the air mixing with the water. And plants release small amounts of CO2 when resting. There is no real need to add CO2, either in a gas or liquid form to an aquarium unless it is devoid of fish. There is plenty of CO2 in the water in most aquariums.
Liquid CO2 boosters often contain Glutaraldehyde, which is a disinfectant used to clean and sterilise medical equipment. It is highly toxic to fish and other aquatic organisms and people have wiped out tanks by adding too much of it. These products should not be used for aquariums.
For aquarium plants to use supplemental CO2, they need lots of light and lots of nutrients. Unless they have the light and nutrients, they won't use a lot of CO2, so there's no point adding extra. To check if your plants are getting lots of light, see if any of them produce streams of tiny little bubbles from their leaves. This is called pearling and is the plant photosynthesising and producing tiny bubbles of oxygen. Algae also does this when given bright light and nutrients.
