How long should my water pumps be turned on for in my hydro system?

I am building a small ebb and flow hydroponic system (thats the one where the tub fills completely with water and then empties out). The plants will be put into rockwool, and then into the tub. How many times a day should my pumps be turned on, and for how long should they run for? (my timer can do intervals as small as 1 minute)

depends on a few different things. lights,type of RW. but ive always had good luck with 2 -3 ,15 min intervals. on botanicare trays with only 2 holes not 4 also running with 2 600 watt hydrofarm air cooled reflectors........try 3 settings of 30 min and if its to much water, work your way down.i would rather have over waterd plants then dead dried out plants

NYC- hey bro wuts up...What system are you runnin...DIY Ebb & Flow...Can you post some pix...Did you say your putting the RW strait into the tray, no net pots or hydroton...I've been posting to you in your other threads to help you out, but haven't got a response back...If you don't want my help man just tell me...sorry for bothering you.....late

I agree with D4. Most questions you start new threads with we have already answered for you. Just trying to help but doesnt seem like your reading what we reply too.