Well I have seriously been slacking with this journal. Over the past week, I have been battling root rot from inadequate dissolved oxygen levels within my system. Due to the fact that I had a relay and two float valve switches blow, I had been forced to manually water. Consequently, the girls were not watered as regularly as they would have been had the control bucket not broke.
During this down time, I have been researching ways to better control my setup. I re-designed a couple of things, and have come across a comprehensive nutrient management profile. I have been reading about the Lucas Feeding Formula. It seems easy enough, and with spreadsheets to create a control track, I will be able to easier analyze trends within the reservoir. I also measured the inside of my reservoir and marked in 5 gallon increments so that I can accurately track water usage and create a reliable addback program that won't harm my plants.
My control box broke because of the sloshing created in the fill line. If you remember, I had to break a siphon in that line, so I installed a check valve at the highest point. It turned out to be a temporary solution. When air would get caught in the line during relay cycles, it would be forced through the line, creating a stop/start which would create waves in the bucket. The repetitive, fast motion burned out the relay which burned out both switches.
I fixed the control bucket today, and re-ran my fill line with a more flexible line. I had to remove everything from the grow room except the tent, and I taped the line in a steady decline which eliminates "troughs" in the line and thus the sloshing totally. I drilled a hole in a 90* PVC elbow joint which joints the hard line from the fill pump to the more flexible line I ran behind the tent. After that, I siliconed everything on that bad boy up and let her rip.
Okay, so for the boring stuff. I started with 45 gallons of water to which I added 400 ml of GH Flora Micro and 800ml GH Flora Bloom. I let it set, and water went from a ph of 8.91 to 5.53 and a TDS of 1136. After 4 hours, the ph rebounded to 5.83. I then ran a fill and drain cycle to get some water into the buckets, as the girls needed a drink. After the cycle, I needed about 6 gallons of water to top of the reservoir back to 45 gallons. I checked ph and TDS again after the addback, and they were 5.9 and 1013 respectively. I then needed to add some more nutes to get the ph down, and because I'm aiming for about 1300 TDS. Using some math, I determined I would need in the neighborhood of 102ml of Micro and 203ml of Bloom to bring the TDS up to that range, + or - 10% or so. Figuring that a batch of 0-8-16 for 5 gallons would be 120 ml, I decided to go with that. I am currently waiting for ph and TDS to stabilize so I can take my post addback adjustment readings.
In all of this, I have determined I have a lack of dissolved oxygen in my system. I have therefore cut my cycles to 15 minutes every 2 hours. I also replaced my 160gph pump with a beefier 240gph pump to help circulate things a bit more in the rez. I have read that a good rule of thumb for air pumps is 1 watt per gallon. My pumps are 3.5 watts apiece, so I am woefully underpowered. I'm feeling confident that once I finally get everything dialed in, this system will be great.