Np. Use those 23 watt'ers. I've seen someone pull 43g's using 2x23w cfls only. They will do fine.Thanks dude , i will keep max 2 or 3 small plants , max 3 - 4 weeks . i m in dilema couse i got already 3 23 w cfl at home , the bigger one of 65 w will cost me around 25 $