if you have to use that much light make sure it is twice as far from canopy as it would be for regular size plants. also you have a humidity dome over them right? clones NEED very high room humidity, 80 - 90 % until they develop roots. i like to mist inside the dome twice a day to keep RH up. a lot of peeps like to use CFLs or T5s for rooting clones as it is a less intense light but still highly effective for growing young plants. hope this helps. GLWyG