How to reduce heat in tent without an extractor fa...

Although closed grow spaces are viable, I doubt it can be pulled off with a tent; most setups I've seen that are like this use a dedicated grow room. You could try switcing the light on during the night, and keep 4 lights off period between 12 and 4 pm, that way you can skip the hotter part of the day. You could use an AC unit, but with all the power it will use, you would be better off using more light with no CO2, I mean what's the point on using a 600w AC? you would be better off setting up another tent or using 2 600 w bulbs. What you could try, is get an cooltube and exhaust only the bulb, that might work and you won't be exhausting the co2. Another thing, although not part of your question, I feel I should point out that feeding a baby seedling at this point is a sure way to burn it to a crisp, specially since you are using soil. The only thing I would feed a seedling at this stage is calmag, and only if your tap water is below 0,2EC (100 PPM). Biobloom is for plants in the flowering stage - post stretch, PK 13/14 is for late flowering plants with fully formed buds in the fattening stage; no comment on bioheaven since I don't use it; Biogrow you can use after the plant use all the nutrietns on the soil. And since you are using 8 gal pots, I don't think you'll need to feed at all.