There are a myriad of different ways to grow using DWC. I don't know how you plan to cool your room via water..hopefully you haven't fallen victom to the hype about water cooled lights. Not going to go there, but lets just say.. waste of money. THE most efficient cooling method is using phase change technology or in layman's terms.. good old fashioned air conditioning. Well, not too old fashioned, mini-splits are the fucking bomb!!
At any rate, before you start talking about nutrient and PH levels, you have to have some plants and system to grow them in first. So lets start with the basics... how many plants can you legally grow and how much light power do you have?
I will say that I run a bucket based DWC set-up with a centralized reservoir. This is not a gravity system but uses a ebb/flow control bucket too empty and fill the individual DWC buckets. The buckets are always full of water (about 20 gallons) and there is an additional 20 gallons of water in the rez outside the room. About every 4 hours all the buckets are drained back to the rez where mixing occurs and then it gets pumped back to the buckets.
The major advantage to this system that I can see are as follows:
1. water levels are always maintained at the proper level within the buckets.
2. the water level can easily be adjusted.. high when young, lower when roots are more developed.
3. By having a rez with a larger capacity than the sum total of all the buckets, the nutrient content, PH,a nd temp are buffered.
4. I can easily adjust the PH and PPM of all the nutrients at once, without lifting up each plant and fucking with each bucket. HUGE TIME SAVER!
5. By having a rez I can also chill all the water at once. I have a DIY chiller that cools the rez to about 60 degrees. The water in the buckets gets to about 73 in 8 hours. When the buckets empty into the rez, it mixes with the cold water...tadah... 67 degree water.
6. A float valve and top off tank on the rez can input fresh water or light nutrient solution during times of heavy uptake and evapotranspiration (late flowering). This is significant, almost a half gallon a day per plant..but I grow em big
7. The biggest plus is probably the automation factor. I got shit dialed and the buffering aspects of the system REALLY reduce management time. I check and record levels every day but there have been times I let the system run for 7 days without doing a damn thing with no ill effects...try that with a bubble bucket! Nutrient changes are extended to 10 days- 2 weeks.
The disadvantages are:
1. The controller bucket is $125 (chicken feed in the grand scheme of things)
2. There is allot of tubing and connections that can leak if you don't take the time to ""do it right"
3. Moving buckets around that are all connected by hose can be frustrating.
4. end of cycle washing is a little more time consuming.
5. You mix more nutes... not sure if this is a disadvantage as nutriient change times are increased due too the buffering capacity of the system.
6. All the buckets get the same nutrient solution...so running multiple strains that are finicky can present problems.
