Haha thanks! I know its so hard to take a picture of "size" to actually see how crazy things are. Yes I switched to brand new HPS bulb when I flipped to 12/12. I use the iPower bulbs and usually only do one - two grows on them. They are cheap. $18 so not worth not buying a new one. You can get more expensive bulbs with maybe slightly better performance and last longer but I rather change them often.
That is correct the water solution is pumped up to the top of the plant that is sitting on my heavy duty tote with two holes cut in it. The pump is scheduled for 15 min intervals, This allows flushing and watering all at the same time to keep the medium perfect. The excess water during this just simply falls right back into the reservior and keeps everything circulating. I use 12 gals - 16 gals in my tank depending on how long I dont want to change it. (Vacation or if im going to be gone). I check pH daily but after the first day its pretty much good to go all week. Very slight adjustments and most of the time thats just me wanting to hold that 5.8 pH that i love. Im fine with anywhere in 5.5 - 6.0 range.
Water change: Water change is GREAT! So easy and take me less than 30 mins. After a week of 12-16 gallons there is only around 6 gallons left in the reservoir. I use a kerosene battery pump to suck the rest of the water out. Everything is done with 5 gallon buckets with a handle (the normal ones that paint come in). Takes about 2 mins to fill the bucket with 4 gallons of water (I have it marked as that is what I fill and drain with in the bucket, You dont want it full as it will spill.) I have two buckets I have to discard of and then I fill my 5 gallon bucket with 4 gallons 3 times and just pour it in the hole thats cut in my reservoir. Super easy! Then just mix in your nutes!
Here is my pump for water changes. This is also what i use to suck a glass full out to test ppm and ph daily. So easy!
Here is me changing the reservoir today. You can see my 4 gallon line in the bucket that has been measured and marked with a marker.
Here I took a picture for you so you can see the holes cut and the setup,
Two holes cut that size. The back one is the pump that feeds (never gets touched) and the front one is for res change and checks, also has a mixing pump (pump with no hose) that i plug in when i put my nutes in. It does not run until then.) I just use my reflective paneling to cover the holes like so. That square piece gets put over the hole when im done.
That is a 7 gallon pot by the way for size reference.
Shes growing like crazy! Shes getting smelly as well... in a good way...