Really nice setup !
I don't know a lot about hydro and I don't seem to see any root rot sings....
But I'll help with the cloning part... Check the picture read this is a nice clone and this little article in the FAQs is good Text
I'll just add that you must! get to clone ASAP in the rooting hormone once cut !
If the plants getting to big you could take more clones, this may stress them a little, usually nothing too bad !
For the air flow I think that your exhaust rate is great with your Can Fan 8" but a pedestal fan or a fan under the setup (Co2 is heavier than air) may be a good idea.
Usually you can see the 1st sings of flowering in 1-2 week.
Why did you're pump stopped ?
Hope this little information can help you. I'll keep checking the log, trying to learn more about hydro !