Help Please

Hi I need your help please folks as the local aquarium centre have been useless. Ive got this red/pink plant in my tank, it was doing well, it shot up and doubled in height within a month, so i cut the tops off to try and make it more bushy.
ever since the lower leaves have gone a much browner colour and looks like they are falling apart. ive attached a picture so you can see.

the new plant growing from wehre ive cut it is doing well, up til recently. it was growing nice and pink as it should but has also started falling apart. ( picture also attached to show you the difference in colour from old leaves and new leaves)

Ive been feeding them with Pro flora fertiliser as the aquatic shop said 5-10ml ever couple days. ive taken out the carbon filters.
my tank is 120L and has 4 cooli loaches, 1 plec, 10 tetras, 6 guppies, 1 kribisis, 1 gourami, 1 glass catfish. ive also been putting the feropol clay balls around the roots. the plants get about 12-14 hours a day light.

im at a loss and the pro flora stuff is costing a fortune. any help will be massivley appreciated.

thanks

Activated carbon only takes out a tiny amount of fertiliser that the effect is negligable. Put the carbon back if tannins bother you and you want clear water back.
What lighting do you have (how many watts)? How much nutrients and CO2 you need depends on how much lighting you have.
12-14hours is way too long. You only need 8hours a day of light.

Have a read of "back to basics"

RadaR said:

Activated carbon only takes out a tiny amount of fertiliser that the effect is negligable. Put the carbon back if tannins bother you and you want clear water back.
What lighting do you have (how many watts)? How much nutrients and CO2 you need depends on how much lighting you have.
12-14hours is way too long. You only need 8hours a day of light.

Have a read of "back to basics"

Click to expand...

cool thanks for that. ive read the link, very informative! ive got 2 20W lights, so acording to the info i should have a total of 120W working on the 1WPG theory. in which case i need 2 60W tubes. have i got this right?
ive also reduced the time the lights are on, it was the aquarium place that told me to put the lights on for longer!

Not 120W of light. You've got gallons and litres mixed up.
To get 1WPG on your tank you'd need around 30W of light. You have 40W alraedy which is great
Technically you have enough light to grow any plant you wish as long as appropriate nutrients and CO2 are given. Do you need to add CO2? Probably not. You should be able to get away with just dosing a liquid carbon product. Seachem Excel. Easylife Easycarbo. AE Design Aqua Carbon. PlantedBox LiquidCarbon. Any of these will do as a daily additive. Follow the directions of the bottle. Do not overdose as it can badly effect fish, shrimp and even some plants.
Next to consider is nutrients. If I'm correct the nutrients you are dosing consists of just trace elements.

To re-quote Aaron from back to basics

There are two main categories. Macro & Micro elements,
Macro consists of Nitrogen, Phosphorous, Potassium (NPK) and Carbon
Micro consists of trace elements such as Magnesium, Boron, and Iron etc. Sometimes these are referred to as CSM+B
Macro nutrients are required in larger quantities than Micro nutrients; here are the targets you should aim for per week.

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Therefore I'd advise you use Tropica Plant Nutrition+ as your fertiliser. It contains both micro nutirents and those all important macro nutrients (NPK). Dose this at 1ml per 20litres.

It's then a case of keeping up the daily dosing and carring out a large water change each week. Make sure the tank is heavily planted with fast growers and ensure the fitlers are working efficiently/not getting clogged up.

can i just ask, what plant is it? Is it a lily?