Base on 230V and current rating of 13Amps, the maximum load is about 3000W. However don't base on the 400W indicated on your appliances. Add another 20% for the losses due to heat etc.
Eg:
MH Lights = 2 x 400W = 800W + (20%) losses = 960W
T5 lights = 4 x 56W = 224W + (20%) losses = 269W
Chiller = 1/2HP = 375W + (20%) losses = 450W
Total power = 1680W
Total current = 7.5A
Still Ok ....
Chiller always have high start up current of about 10 times the running current. So must give some allowance. Try not to load the plug to more than 10Amps or 2300W if there is a chiller connected.