rejuvenate 4 feet tank

[angus]

HI,
my 4ft tank has been setup for about 1.5 years. The growth of the plants seems to have stopped. as shown in the pix:
1. the java fern black dot spores are turning dark bigger black dots - think they are dying.
2. the orange aquatic plant - pix middle left leaves are thinning. don't think they will last.
3. The bacopa growth is slow and does not root well.
4. the tenullus used to florish but now are barely surviving and some are caked with black algae.
5. The middle right red plants are just planted- probably will not last.
Lights: Greenelement 4ft x 32 x 3w LED, on daily about 4 hours
CO2: > 1 bubble per second.
ferts: LushGro Aqua with additional K, N, S in min amounts.
soil: Gex 9l x 2 (1.5 years old)
water: clear and algae generally well contained.

Let me know your thoughts on what can be wrong (lights, fert, CO2, soil,etc)....
I am thinking of adding another 4-9kg of amazon soil to improve the condition. what do you think?

[Urban Aquaria]

Instead of adding in more soil, perhaps consider just inserting root sticks or tabs into the existing soil, it'll help restore the nutrient capacity of the soil to directly benefit the rooted plants, so you don't need to go through all the unnecessary cloudy mess and ammonia spikes.

Your current 4 hour light photoperiod is abit conservative, i know some people do that to reduce the chances of algae growth... but in tanks with plants which are faster growing, short photoperiod tend to limit their growth and natural tissue maintenance, so the old leaves don't get replaced as quickly and the whole plant becomes stunted.

Since you have Co2 injection, maybe try gradually increasing the light photoperiod up to 6-8 hours, and also increase the Co2 injection and fert dosage accordingly too.

As for the algae coating the tenellus, its probably occurring due to the restricted plant growth (which turns it from fast grower to slow grower), so algae naturally gather and grow on the slow growing old leaves which are deteriorating and leaching nutrients. Improved light, Co2 and nutrients can help speed up new growth and ward off algae accumulation. At the same time, improve the circulation around those plants and introduce algae eating shrimps like amano/yamato shrimps, they will help to pick and clean algae off the leaves.

Hope that helps.

[welly]

Wow your tank looks crowded bro