Saber

Forgot to say you can use a fresh water ph test kit from a pet store that sells tropical fish. It should use a ph range of 6.0 to 7.6 typically. Test your tap water first you would like the ph to be between 6.0 to 6.5 for soil grows if it is too high you can use a few drops of white vinegar or lemon juice (acidic) to lower it. To raise it you can use Sodium bicarbonate but use it sparingly excess sodium is not good for plants. Also if your water has chlorine in it leave it out in a bucket overnight stirring it several times for the chlorine to gas off.

The one plant that's really yellow looks like the leaves are drooping down a bit it is a sign of over watering. The root system is still very small for the size of the pot. More than likely the lower and middle of the pot is still wet when the top starts to dry out. If you lift the pot you can get an idea of how heavy or light it is to help give you an idea when to water. Let them dry out a bit more than usual then stick your finger into the soil up to your first knuckle to see if it is dry. Using both of these ways to gauge when to water. If the soil is too wet the roots can't pull in nutrients properly. Everyone is guilty of over watering at some point or another.

As they started flowering you should also give flowering nutrition from now on, at best you follow your feed chart for your nutes. Let´s hope they will stretch during flower.

@Saber, Yes you can use your bloom nutrients. What were you able to come up with for nutes? What is the N-P-K of the nutes? I see your still struggling with heat issues. I guess when it's over 100 F outside it's not helping you out much even running an air conditioner. I would suggest only running your lights on 18 hours a day and 6 hours off. Try changing the time on during the coolest part of the night and off during the hottest time of day. They will like having a bit of rest and this could allow them to cool down. It would be nice to have a 7 F to 10 F day night temperature drop your at 5 F which is bare minimal.Keep in mind that if you are using a HPS high pressure sodium bulb they put out more infrared light which will cause the leaf temperature to be 8- 10 degrees higher than the room temperature which can stress them out a lot.It is very possible the leaf temperature is close to 90 F. The reason you want lower temperatures and proper humidity levels is it will cause the leaves to open their stoma located under the leaves when the lights are on. The stoma take in Co2 to create photosynthesis activity. If leaf temperatures are too high and the humidity too low the stoma will close which will also slow down how much water and nutrients can be pulled through the roots. This translates into your having "Leaf Vapor Pressure Deficit" issues. At those temperatures you would need a very high humidity level which would be bad for the buds and cause mold issues. These heat issues will simply cause smaller loose looking buds and it can burn off terpenes effecting the smell, taste and potency of the bud. You have some very difficult growing conditions to deal with. Some tropical/desert growers take a break and grow during the cooler seasons to maximize their grows. Good luck I will continue checking in on you.

Looking a little closer I think you may have spider mites.... I have no experience with these and it looks pretty infested tbh