I'm now on the winning side of dialing in my new aeros. It took me a lot of runs and I'm seeing saw teeth at 6 days, roots at 10 or 12 days.
I understand that there are many people who get roots in 4 days, kudos to them but I'm not one of 'em. It took me a bit of fucking around to get to this point and here's what works for me.
Water: I tried distilled and tap, ph balanced and unbalanced. Right now I use plain tap water unbalanced.
Additives: Once I got some RapidStart by GH, things got better. I have clear rez and a root protector solution that came as samples and I haven't needed to use them yet.
Temp: My res temp stays near 70.
Air: I rock an airstone in my turbokloner T-24 and another airstone positioned in front of the intake fan that blows air across the water in my res (a cool design) so I'm getting heavy O2
Technique: I started diluting my clonex into water and soaking my cuts for 20min after making small nics in the clone stalks with a STERILE knife. I sharpen my paring knife and soak it in denatured alcohol before I start hacking. I don't cut my leaves down. I want them to want to suck water.
Timer: I tried quite a few variations and now just leave my cloner running 24/7
Light: Cheap fluorescent tubes about 20in away, left on 24/7. I don't use a humidity dome.
Cleanliness:
I don't know if you've ever brewed beer. If so, you know about compounding effects of ill sterilization upon contained water... If not, I'm sure you can imagine. I deep clean my system between every run.
This entails the following:
Put fresh water in res with bleach, run pump with pucks in place 20 min
Dump water
Scrub res tank, lid, pucks with scour pad
Dismantle and scrub pump parts, rinse filter of debris (the type/amount of debris in your pump filter will lend valuable scrutiny to your cleanliness)
Soak pump parts in warm water
Remove nozzle heads from pipe/spray manifold, rinse under hot water.
Toss in the bleachy warm water with the pump to soak another 5 min
Rinse everything thoroughly, re assemble
Run new water for a few minutes and drain the res
Refill, run another 5 min
Dump, Dry.
If you run airstones, disconnect and soak them in a hydrogen peroxide solution (submerge the cords so the h2O2 fills the lines) You should see the h2o2 start acting immediately and start pulling all sorts of crap out of the innards of the stone. Or you could buy a new stone (2$)
Dump the h2o2 and soak in warm water for a few minutes.
Reconnect it and let it run in the warm water to flush
Give it another soak in h2o2 and rinse again.
If at any point in time you see shit floating in your res or the water smells off, change it out and add more rapidstart or whatever you had in it the first time.
If you decide to use RapidStart, use just a touch more than they call for under 'aggressive use'
'Between 68 and 75 degrees' may be too large of a variance if this fluctuation is occurring daily. Perhaps move your system to a more temp stable spot (away from windows, vents, appliances)
No need moggggys right, if your pump and/or airstone are working properly, your res will have enough agitation to evaporate your h2o2 very quickly. If you're using this as a preventative measure, consider a potassium based solution instead.
However, your problem may not lie in toxicity at all. I'm saying you probably don't need the h2o2 at all.
I'm inclined to believe that improper sterilization of your equipment is to blame if you've gotten results before.
Hope some of this helps.