Originally Posted by fishfirst
Sorry for lack of information. Please find below:
-tank size is 4ft (L) x 1.5ft (W) x 2ft (H).
-lighting: 4x54W light open for 7 hours daily with CO2.
-Temperature: 28 degree C.
-I put JBL aquabasis plus as the base and holland sand on top of it.
-no additional fertilizing since first day.
Thanks for the information. My first thought is that there are insufficient macro- and micro-nutrients to balance the light and CO2.
From your tank dimensions this is a 90g aquarium, same as one of mine. You have 216 watts of light which is a lot, but you also have CO2 so that is OK. If the tubes are full spectrum with a kelvin around 6500K that is good plant light. You don't mention the pH and hardness of your water, which could be a factor, but assuming the CO2 lowers the pH to slightly acidic or slightly basic and the hardness is not too high, I think the nutrients are the issue.
Plants require light and nutrients in order to photosynthesize (converting sugars to energy which is how they grow), and these must be in balance. Nutrients includes CO2, macro-nutrients and micro-nutrients. Dealing with the latter two categories, some of these may be in your tap water (varies, depending upon the source of the water), and some are produced through the biological actions of fish and bacteria in the aquarium. But some will be missing and must be added.
The best fertilizer is one that contains all the macro- and micro-nutrients that plants require, and in the proper porportion. Dosing individual products like iron, potassium, zinc, magnesium, copper is risky because there are many nutrients needed and in varying quantities, and sometimes an excess of one of them can cause plants to alter their chemistry and certain other nutrients cannot be absorbed. The safest way to fertilize is to use a balanced comprehensive liquid fertilizer. I and many others on this forum recommend Seachem's Flourish Comprehensive Plant Supplement. Years ago I had good success with the Kent Freshwater Plant Supplement. And there are a couple of other brands that work according to others, that I have not tried so I wouldn't like to suggest something I have no experience with. Seachem's Flourish Comprehensive is good; just make sure it is the "Comprehensive" as they have a number of different products in the Flourish line.
I dose Flourish twice a week. I have experimented a couple of times, reducing the dose to once a week from twice a week, and both times the leaves on my swords began yellowing and becoming transparent; within 1-2 weeks of returning to twice a week they recovered (the new leaves were green, older yellowing leaves usually die off). I would recommend you get a bottle of Floursh Comprehensive and follow the instructions on the label. You can try it once a week and if after 2-3 weeks there is little or no improvement, use it twice a week and see if it improves [note, the existing leaves if yellowing now will not improve, but new growth will be green and lush]. I dose it right after the weekly partial water change, and then 3 days later, in the amount given on the label. For a 90g tank it is about 1.5 teaspoons each dose; doesn't take much, but it does work.
From the 54w tubes I am assuming the lights are T5 HO tubes, and full spectrum. These produce a lot of intense light for their size, which makes it even more imperative that the macro- and micro-nutrients are added. Let us know the results after a few weeks. I would guarantee this is the solution. I'm attaching a photo taken yesterday of my 90g Amazonian flooded forest aquarium which is thickly planted. It has two 40w tubes of full spectrum light, no CO2, and twice weekly Flourish Comprehensive fertilization. This has been the regime in this tank for 9 months, and it clearly works.