Im ordering a fixture for a 20g clam tank I added to my system. The fixture is actually for plants and comes with 4 24" 6500K HO T5s bulbs. Is this spectrum adequate for photosynthesis or do I need to get 10ks. Im really just trying to keep things cost effective at the moment and I dont really feel like spending another $70 on bulbs. I do plan on upgrading them in the future.