I thought I posted this here already, now that some people are dabbling with hydro/aero this may be of use to some. I thought I would share how I modded a $15 96pin 2 outlet timer from Lowe's to run a 40min cycle with 25s increments instead of the 24hour 15min increment stock operation. A very simple mod, it actually makes the timer work more consistantly as well. The case is secured with 5 screws, remove them and lift the cover off like in the first pic. The gearbox is where we work, only 2 changes are made. In pic 2 I'm holding the gear in the spot it was originally in, remove that gear completely. Flip the blue gear upside down and replace it, this will make it to where the blue gear is contacting the 2nd gear from the bottom in the row to the left bypassing the one below it. I leave that unused gear in the gearbox to act as a spacer for the gear above it. NOTE: You can see in the first pic the magnetic motor assembly has one black arm and one silver arm, don't reverse it when you reassemble the gearbox or the timer will not work properly. Reassemble the timer and voila! Timer used: Utilitech 2-Outlet Dual Mode Timer #0143158, Philips head screwdriver, steady hands. Some Lowe's may not have this model anymore but I've had reports back that the same gearbox is used in other models, YMMV
Alternatively this guy made an ebay business of doing the same mod, still a ton cheaper then a CAP cycle timer. http://cgi.ebay.com/Repeat-Timer-Fixed-40min-Cycle-Timer-Aero-Hydroponics-/220692718630?pt=LH_DefaultDomain_0&hash=item33624fa426#ht_1531wt_1135
