bro,
sorry if i came off as angry. that was not my intention. my point is that by you still talking about the blacklight, shows you have not done your research in the right areas. your black light is an incandesent bulb. first issue is, it his highly innefficient ie;lots of cost not much light. second issue is lumen output. the lumen output from a sixty watt incandesent bulb may seem bright to you, but to a plant its like the sun on a black stormy day. to grow succsessful plants with dense, large buds and high yields you absolutely need at the very least 250 watt cfl bulb in a small, enclosed, reflective space. and this would only be enough for one, by my standards, modest plant. and as far as variables go, any successful grower will tell you the less variability you have the better. i agree with trying slightly different things on a small level that are based in science, this can yield successful results. please do not get offended, my goal is to help you grow better plants brother. peace