You can do stand-alone 5gal coolers, but I prefer the larger coolers for more plants per cooler.
Go to Walmart for the 48q/12gal Igloo Marine coolers, or larger. Even Sam's Club for the REAL big ones like Bloomer57.
Preferably white coolers to refract the light.
Plus the Marine line of coolers were made to be on boats in the sun all day.
PERFECT for grow rooms under intense light !
No need to flush out the water and clean weekly as long as your res temp are cold enough (below 65F) and you replace the water/nutes that were eaten with fresh ppm's and ph'd solution every 1gal or more. Especially during bloom, which is when they eat/drink the most.
I would easily replace 1gal a day in a 12gal cooler with 10gal of nute solution.
I use Rez Doggs formula with powder Kool-Bloom, also here on RIU somewhere.
Again, no need to remove plants because no need to flush and clean until after the chop and harvest.
That includes males that show sex after bloom starts. Just cut the stalk and leave the root system in the cooler with the females the entire grow. I show proof of this is my threads too. NEVER AN ISSUE ! Just healthy roots on a plant that is no longer growing, along with the females that are left for bloom.
Look back a few pages at my cooler lid that has a corner cut off, to move for adding back nute solution to the cooler.
Simple and easy to use/do.
I use either 1gal or half gallon juice containers (like Ocean Spray, Gatorade, or Great Value[Walmart Brand]) to add back nute solution.
Be sure the solution you are replacing is the same ph and ppm as the cooler res for whatever stage of growing you are currently in.
I also use the half gallon bottles and fill about 90% with tap water and freeze them.
I keep one frozen bottle in each cooler, and switch them out at lights off and lights on, especially during bloom.
If your ambient air temps are 77F or lower, then the cooler res temps will stay below 65F.
Proper res temps will allow you better growing without worries of res bacteria, which hate cold temps so no root rot to worry about.
Stable and cold res temps also is what is needed to have stable ph readings.
TEMP AFFECTS PH !! WARM TEMPS = PH FLUCTUATIONS !
PH AFFECTS NUTES ABSORBED BY THE PLANT !
PH TOO HIGH = VERY LITTLE MACRO AND MICRO NUTES FROM BEING ABSORBED !!
I even posted info about that too a few years back.
Hydro grown buds like colder temps and lower ph than soil grown.
Best ph is 5.9 to 6.2 overall !! Hydro or soil !
You most def need a ph, ppm and temp meter. A combo meter of all 3 is even better and what I use.
I use a Milwaukee brand combo meter.
A 600w bulb is watt for watt THE best grow bulb. Good for a 4ft x 4ft area, versus 5ft x 5ft for a 1,000w bulb using more electricity for just an additional 1 - 3 plants.
For mature plants that are at least 3 feet tall, I never put more than 8 plants under a 600w Hortilux bulb. I also cut the bottom nodes that are more than 3 feet from the bulb. No popcorn buds taking up precious nutes since they get hardly any light. Waste of energy, nutes, and hurts the final yield !
Look up the Inverse Square Law. I even made a post about on RIU if you can find it. VERY USEFUL for not wasting light and grow space.
I stopped growing, but try to drop in once in a long while and offer any consultation if need be.
Hope this helps !
