# RDWC Control Reservoir



## grodude (Feb 24, 2015)

What size should the control reservoir be in relation to the plant buckets? I've heard people say it should be larger, not sure by how much, but I see a lot of rdwc setups on Youtube with a 5-gallon bucket setup and a 5-gallon reservoir. Hygrohybrid actually uses a much smaller reservoir than the size of his buckets.

I was curious to hear your input and why you feel that is the case. Thanks


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## Hushpuppy (Mar 1, 2015)

I prefer to have a much larger reservoir if possible. The more water you can keep in the system(within reason) the better it will be for you as you will not have to adjust pH as much or change the solutions as often. Having a single DWC container (5gal bucket) means that you will have to change the solutions at least every 5-7days. I have a 3 plant tote system that holds 35gallons of water. When I set the system going, I don't have to adjust the pH for 3-5 days, and I don't have to change the solution but every 2 weeks. I do have to top up the solution as the plants drink up the water, but I only add straight water, adjust the pH and let it go.

There is some variation to the times for adjusting and changing due to different environmental conditions that can cause the plants to drink more or less, or eat more or less. But I am able to set my pH at 6.0 and then as the plants eat and drink, (my) pH goes down (as is the nature of the nutes that I use, AN Jungle Juice 3part) until it gets to 5.3 then I adjust it back up to 6.0 and let it go again. By the 3rd adjustment off pH, the plants have stripped ~80% of the available nutes from the solution. I can tell because the pH will drop quicker as there is less available nutrients to take up. At that point I change the solution by pumping out the rez and plant totes, which also hold water, and then refill with a ffresh batch of solution.

I don't have to pull everything apart and clean it until after every other grow cycle. When I do a system solution change, I just drain all but some tiny amount of water (maybe 1-2qts at most) that gets left behind in the totes. Then I refill with new solution, do final pH adjustment and go for another 2 weeks.


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## sopappy (Jan 1, 2016)

grodude said:


> What size should the control reservoir be in relation to the plant buckets? I've heard people say it should be larger, not sure by how much, but I see a lot of rdwc setups on Youtube with a 5-gallon bucket setup and a 5-gallon reservoir. Hygrohybrid actually uses a much smaller reservoir than the size of his buckets.
> 
> I was curious to hear your input and why you feel that is the case. Thanks



 I'm stuck with a smaller rez but both my systems are small 2 and 3 bucket systems. When I bought it, I wasn't coming here and hadn't realized how 'old school' it was. The grow shop was using it so I copied it. A small rez is more just a port hole to add or drain solution, and adjust levels. I also have to change more often. I can't see any benefits, I think the small rez (add-on) was just a quick-fix to having to lift the plants out of the buckets.


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## zem (Jan 1, 2016)

a larger res is in many ways better, I use 200liter res with about half of that 100 liters of root space, i used to switch RDWC and flood and drain with the same res. i was able to travel 16 days leaving it on a timer, and the drift in nute and ph levels is less than with a smaller res


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