Yellowing bottom leaves, is that normal??

Hi everybody, I'm a first time grower and I just want to know if this is normal. My babies are about 3 weeks old and I'm using a 1000 watt light bulb. I have the light fixture about a foot to a foot and a half away from the top if the plants. It seems to be just the bottom leaves that are starting to form yellow sploges and burnt tips. I think maybe it has to do with the light or it has to do with to much watering? Idk so hopefully someone can help me with this problem. The first one is the GSC and the 2nd one is the cherry OG, the little one in the blue cup is gone, I ha to get rid of it because it was also forming yellow spots so I just got rid of it. So right now I only have those 2 in the big black pots.

ease up on the nitrogen.. also lookslike when your watering your plants that your getting those lower leaves wet with nutes and burning them.

This is my 2nd grow and I can say that my bottom leaves always got yellow, I think there is no need to worried ...

Okay thanks a lot, so what should I do to ease up the nitrogen? I'm using guano compost tea, I just add it with my water, and I've been using ocean minerals in the water. Other than that, that's the only thing I'm doing to them.