Q about drip system

I have my girls in a 28 site drip system (have only 24 plants though). They are in a rockwool slab medium. I am just starting week 6 today. My question is about drip times.
I have the pump going 4 times a day (every 3 hours) for 5 minutes. The slabs seem moist but not saturated. The leaves do not seem droopy like they have been overwatered. I would just like to know if someone has a similar type system and medium, and what their times are.
Also, I have read that it is good to flush the medium a few times because salts can get locked up in the rockwool. I change the res every week (25 gallon) and like WH, I take half the res water out in the middle of the week and put fresh water in with fresh ferts. I do a small flush at the end of week 5 using just water, cal-mag, sweet, 5 ml of LK, and snowstorm but do I need to flush again sooner or, with keeping up on a fresh res, am i okay?
I have also looked at the cocoa slabs that came out. Are these better then the rockwool that I am using?
and one more question...My res has a heater and stays at 69 degrees. my temps get to 65 at night. Should I have a cycle going in the middle of the night to keep the root zone warm or are they okay at 65?

Thanks

I have worked ebb and flow with rockwool slabs, but I really don't think that rockwool is the best media for a drip system. I would be pleasantly surprised if someone would really think that its the best system... although it would probably work.

I feel the clay pellets/hydroton is really the best and easiest to regulate. Rockwool takes so long to dry out, and I feel if you are not right on, you may well end up with some kind of root rot. No problem with hydroton. Other advantages come at harvest time. You have those expensive slabs, all wet, to get rid of. I rinse off the hydroton and it can be re-used..... a lot less to take to the garbage can...

Thanks for the reply SpaceNeedle. I know what you mean about the trash haul. Root rot is not that much of a problem when using Hydroguard and hygrozyme. The roots always seem to be nice and white when cut down at harvest. The drip system is made for rockwool slabs or the like in size. I can take a picture of it when my lights come on. The slabs have a return connecting into a support pvc pipe which dumps back into the res. The openings are just the right size for the hydroton to escape and dump down into the return pvc pipe. They make coco slabs as well. I will post a pic in a few.

What about going to Lowes/Home DePOT and picking up the top section of a drain for a bathtub? Not sure how big around your drain is but if size is right it would allow you to use hydrotron and not have it go down the pipe. :thumbsup:

So I finally had the time to take some pics. As you can see the system is made for slabs. Next round the trays that the slabs fit into will be angles so that all the water leaves. Normally there would be a tiny bit of water left on the bottom of the tray but the slabs don't seem to concentrated with water.

They are in week 7 of 8 of flowering. They are a bit streached but the buds are super heavy due to the gravity. I project over 3 pounds from 24 plants under 1600 watts. Thats 1 watt per gram over 2 months or .5 gram per watt per month. The system can take 28 plants and not all the clones were large. I project out of my 8x4x6 foot cab and 1600 watts I can get over 4 1/2 pounds every yield.

Custom odor bucket filled with a small Ona gel. This thing works like a charm the last 3 weeks.
A close-up of a smaller bud (thank you snowstorm)

No reply?:wtf:

Maybe we are all choked up on drool ;)
That's great. Really. It is rare for us to see a successful slab grow here at canncom, so yours is a treat.
You got a plan for all that trim yet? Mmmm caramels... lol!

Wow, thanks! I guess I really don't see many people grow with this type of system either. I guess that is why I can never find out the proper info. It has been a really easy system to operate and I am almost at full capacity.
I think I will keep the rockwool slabs but I have decided to put the trays at more of an angle so that all the water flows out of the trays and back into the res. I bet this will make my slabs dry, faster. So I will most likely have to adjust my watering times again, but at least the slabs won't sit in a little bit of water.
It is turning fall in there and I am trimming off some yellow leaves. They will be harvested on monday and all the heads are milky white with some turning to amber. The hps lights are not good for accurate color, so I will take some pictures right before the lights come on and at harvest.

Thanks again!

As for the Trim you ask? I put that through an 8 screen bubble bag system. I then take the leftovers in the work bag and make some insane butter. I need to try those caramels though. Can I use the leftover trim in the work bag to make those as well?

Yup. Leftovers from a physical extraction are perfect for a second, chemical based (=lipid or alcohol), extraction.

What's the spacing between all of the girls?

About a foot in between the trays. Next time I will have about 4 plants per tray. 28 plants under a full load. I have my yield drying right now in the cab so in about a week I will snap some pictures of the clones being transplanted into the trays. That way you can get a better picture of what the spacing looks like.