I need a 7 circuit programmable timer

Im building a large hydroponics table. the table is 6'x6'x1' with 6 individual troughs that will flood and drain separately. How it works: the controller / timer I need help finding calls to irrigate trough #1, control valve / low voltage solenoid for trough #1 opens, pump starts, trough fills up through hole in bottom of trough, water starts over-flowing into over flow tube back into reservoir, after 15 minutes the pump stops, all water drains back into reservoir through the control valve and pump, when the trough is empty then control valve for trough #1 closes. All of this is going to have to be tried out and timed then programed into the control. Anyways I spent some time at the local hardware stores in town and found all the irrigation controllers / timers have very limited programming capabilities. the only other idea I have is to use a digital light timer in conjunction with an irrigation controller. The light timer would control the pump separately from the control valves. I don't see a problem with that idea long as both the light timer and sprinkler control keep the same time.

If I was doing this, I would use one of several old DOS-only laptops I have laying around. Most of these were purchased at garage sales for ~$10. Where else can you buy a controller that has a disc drive for program and data storage, a keyboard, an 40x80 character LCD display, one or more serial ports, one or more parallel ports, built in real time clock, power supply, etc?

I use QuickBasic 4.5 as a programming environment; DOS for file storage... The parallel port can sense/control about a dozen inputs/outputs.

I have done several data-logging/control applications with old laptops