You may check out some local forum like my-mac. Read up on water cycling, bio filter, lighting, fertilazition, co2...etc. Important to get your setup right and know about your plants requirements and maintenance. Welcome to the hobby.

shahrul, 2 school of thoughts :
1) 24hr co2 : should be low count to keep ph stable in the tank. when lights on, plants will have ready co2 to use.
cons : wasted co2 at night when lights are out.

2) co2 when lights are on. it will take a while for co2 to circulate around the tank. so lights will need to be longer than option 1 so that plants can fully utilise the co2 for photosynthesis.

- if your fishes are always at the top gasping for air, that means too much co2!! turn it off and add some water disturbance at the top to add oxygen back into the water.

for me, i tried option 1. it was when i only got a manual regulator. i put on 1bps and leave it on 24hrs. i left the lights on for 6 hrs. plant was slow growing.

then i try to turn on higher to 2bps when daytime and turn off in the evening. it was tiring and sometimes i forget. lights on 6 hrs as well.

now i installed a solenoid valve and turn up to 3bps when lights are on. but only 3 days when my co2 ran out and now awaiting refill... haven got clear results.... will update more when my co2 gets refilled.

sorry only java or same with other plants??

if java just trim it and let the new growth....c how

i meant the affected plant? only java or other plants as well?

dont think water current will effect the look

Hi Mr Shahrul09, I agree with mr bartbarb. 24 x 4 is very strong for a 2 ft tank.

hi. more light = faster growth = more co2 + more nutrients and vice versa. which means u can maintain ur lights but scale up your co2 on par with your lights  to a point your fauna cant stand and use high doses of nutrients or you can try to reduce your current bulb to 2 or 3 bulbs or u can raise your light fixture with 4 bulbs at least 15 to 20 in from your substrate. lower lights will make your riccis grow slower but beware reducing lights will make ur plants in stablizing mode for a while before rebound back to normal growth. regarding current flow yes it will helps your plants to use the co2 efficiently. it is in this way they can consume the co2.. many thanks.