u can always get some flourish excel (liquid carbon) can get expensive , also DIY CO2 witch is just fermenting yeast and sugar to produce it and diffuse it into the water with diff methods (good for most tanks) if really large tank pressurized CO2 would be way to go to get enough saturation in tank . i am about to go get a presurized system but DIY has worked well for me for a long time with good results . but i am big on basics ,lotsa of more knowledgable people on here that can help further
oh and i know nothign on LED ligths , i have t5ho