The blumat system allows soil growers the freedom to run their environments like hydro growers do without the need to frequently adjust ph or add nutrients as the soil buffers ph and nutrients are added by topdressing or one could make nutrient “spikes” to place just under the sensors and/or drippers…if doing soil drenches, simply turn down the carrot allowing the soil to dry out more as it can go anaerobic if the soil cannot “breathe”
Now lets talk about the different choices Trompf offers…
Single plant or “Junior” is just that…single pot with its own soda bottle water reservoir. Being so small, water flow is really slow - too slow for our cannabis plants…even little ones in 2quart pots as the roots will wrap around the sensor to siphon the water faster. These are put to use in my window boxes or set a 1-2 liter bottle on it to replace the cap if I know I can’t water my houseplants for awhile.
Original… the one that started it all! When they 1st came out, they were restricted to 1 per plant or every 6" around the pot. Since these are controlled by an individual tensiometer in the cap, you control the flow rate. These are great for raised beds, plastic pots and shallow fabric pots. Though many run these in 3-7 gallon size, I personally do not like them in more than a 3 gallon as the bottom dries out faster than the top in my environment leading to plants with shallow roots…those in more humid environments gets the best use of these.
Maxi’s… Trompf’s answer to the Original’s shallow watering as the sensor sits much deeper in the pot. For the people that already invested in the Original’s, they recommended to stick one of these in the bottom of the pot with its own dripper…combining the 2 allows for watering throughout the pot though harder to dial in and who wants a hole in the bottom of a pot? I don’t and believe it is overkill unless in a raised bed taller than 2’
Accessories
Drippers - these truly are the answer to less equipment as they act as an extension of the sensor effectively watering a 6" circular area…for this reason, the 1st dripper needs to be within 3" of the carrot otherwise the soil may become waterlogged as the carrot needs to be rehydrated before it shuts off or runs out of water. Also, if you run nutrients in the reservoir they need to be loosened to allow the “thicker” water through and may become clogged in between the sensor turning them on/off leading to dry spots. and killing off roots as well as, microbes…learned my lesson trying out megacrop through the system - dismantled each dripper 6 times in 3 months.
Soaker hose - I still have yet to try this though from what I see, they are excellent for large beds to replace all but 1 dripper though many say that they make the soil too wet as they do not turn off right away like the drippers do.
Pressure Reducer - eliminates the need for a reservoir as this allows hook up to a water line whether it be from a hose or shared line from like an auto ice cube maker. While they sound awesome, I personally do not trust it because a reservoir runs out of water eventually if/when the sensor loses its calibration leading to flooding.
Digital Moisture Level Sensor Meter - Now I really don’t get these though I suppose it would be beneficial if someone had a difficult time setting the carrots up or extra security knowing what moisture # a pot has in a 6" area…some say 4 while others say 9. I rather rely on what the plant shows me as they hit spurts of non drinking and spurts of guzzling like no tomorrow depending on what stage they are in or how good/poor the root system is.
There are many diagrams for set up idea’s
Really all one needs is a reservoir, tank connector, 8mm tubing, 3mm or 1/4" tubing, 1 maxi per 3+ gallon pot as there is more freedom in choosing depth or a Junior for up to 2 gallons, a few drippers for even watering and a couple of shut off valves so one could remove the reservoir for cleaning and/or bleed the lines…if a reservoir cannot be at least 2’ above a pot or a larger reservoir is wanted, throw in a pump to circulate it though imho, the gravity fed style is what made this system so attractive…that and having a smaller 3-5 gallon reservoir eliminates the need for conditioners, bubblers etc as it gets used before the water goes stagnant.
One last note
Do not be tempted at the carrot knock offs as they do not have a ceramic sensor which is crucial to the efficiency of the whole system…everything else can be from any company as long as the size is correct 
I hate Duh Rev’s TLO book…
tape measure used when transplanting. my dad used a bubble-level too. 
can’t have an asymmetrical hedge now, can we? ayayayyyyy…