The espresso pump is fine. It's the black chinese pump that you ordered that sucks. It was impossible to deal with. I was going to have to build a plywood box with acoustic wool blankets or something. Totally not worth it since that would cost way more than the espresso pump did. You probably do still want to wrap it with a bit of foam though. Walmart sells foam used for seat cushions in the sewing section that works pretty well.
Here is the pump I got:
https://www.amazon.com/gp/product/B00NMNA138/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
I don't have a grow log but I'm between grows right now and I'm going to start one as soon as I start up again. I'll link it here.
It's just the one pump. I don't even have a backup because I think this one will be reliable. I will probably buy a backup pressure switch though because the one I have is from china.
I have the plastic accumulator. It's totally fine. Although I would probably be ok with a larger one too. Just make sure if you get a bigger one you attach a T connector with a valve so you can empty the accumulator back into the reservoir every time you change the water. Otherwise you'll have like 4 gallons of old water stuck in the system that might take days to go through the misters.
Right now I'm at 0.25 seconds on and 4 minutes off, but this depends totally on the size and shape of your root chamber and the number of misters + their flow rate. I'm building a larger chamber this time so it will probably require longer on times. It needs to be long enough to completely fill the chamber with mist. It took me forever to figure out that I needed sub-second on times and almost 5 minute off times. I started out with 3 seconds on and 3 mins off. Total root rot! It might work fine with another setup, but not this one. You have to experiment wildly. I'm probably still not getting it dialed in perfectly. My next setup will have two identical chambers on separate solenoids with individual temperature control and spray timing for each root chamber. That way I can A/B test different conditions to see which one does better. Otherwise you're just guessing really.
I have tons of cool sensors but I'm not using most of them right now. I have a leaf turgidity sensor that measures when the plant actually needs water long before it actually gets drought stressed and wilts. You could control the spray times with this but for now I'm just using a timer. It's on my list of things to try though. It should allow me to save water and improve growth rates.
I have a heavy-duty steel-enclosed temp/humidity sensor from sensirion. I use it to control the atmosphere in my tent. The DHT-xx sensors didn't work for me. The small amounts of mist in the air eventually corroded them. It's well worth the extra money because you'll spend at least that much replacing the cheap ones.
I use a bunch of solid state relays to control a humidifier, the exhaust fan for the tent, the root zone cooling system, and eventually I'm going to hook up a bunch of peristaltic pumps so I can automatically dose pH up and down as well as liquid ferts. I have the pH sensor but I had some problems with bio-film messing the readings up so I put it on the back burner.
The root zone is cooled by a peltier junction (thermoelectric cooler) and a heatsink and a bunch of parts for water-cooling computers. It's not as efficient as a big compressor-based aquarium chiller, but it's quieter and definitely cheaper to put together. I think maybe $100 worth of parts. Before I got the chiller even with the AC cranked so the tent was 75F, the roots were still overheating and dying. Once I sorted the root temps out it was smooth sailing. Now they can tolerate low-80's in the canopy without any issues at all.
I used a 400w induction light last time, this time I'm going to add a couple white-led panels to up the wattage so I can do a v-scrog in my 5x5.