From Soiless to Hydro

So I have been really considering going from soiless media (Pro-Mix) grow to Hydro.
There are endless setups, but I am thinking about a system with six grow sites with reservoir and chiller.
I have an 8x4x7 tent for a hydro set up. (I have a 4x4 and a 2x4 for mother plants, seedlings/cloning etc.
My question is what size buckets should I use for the plants? I plan on 6 plant buckets.
This is the chiller I thought would work for me.
Any thoughts or advice? Any lessons learned would be super helpful along with equipment suggestions.
@Donaldj @TDubWilly @peachfuzz @Vexer


These would be a good size with a larger tote for your recirc reservoir for RWDC


I like the square shape. I have read a few people thinking they are better to seal than round buckets.


My 5 gallon walmart buckets work great @<$5 a piece, but wish I has square. I don’t run R-DWC though.


Ok going hydro, sounds great!

That’s a good chiller!

For me, hydro is a game of consistency and that’s what I try to keep in mind when building a system. I don’t want anything swinging back and forth in my system. Temps and pH I try to keep as stable as possible.

The chiller will have you covered on temps unless your already in a real cold area. Water volume will help with the stabilization of pH and help keep ppms from getting into any kind of toxic levels as the plant drinks.

A system that holds ten gallons will be much more stable on pH and ppms than a system that holds 3 gallons.

If your there for your plant every minute of the day them this isn’t really a big deal but if you go out of town over night you will be thankful you have that extra water, especially later in flower

Also aeration is very important. I like to have my water look like it’s at a “rolling boil”. Invest in a good air pump and choose air stones that tend to make more smaller bubbles than fewer larger bubbles. This will make it easier for the oxygen your pumping in there to dissolve into the water.

That’s all I can think of for now. Have any more questions then just ask!


If you were going to do RDWC, I highly recommend having your primary reservoir outside of your tent. It makes life a lot easier and definitely go with the square buckets that are a minimum of 5 gallons or more. I think the 7.5 gallon buckets are perfect. You really need to just be diligent about checking temps and pH because those are the fastest roads to root rot. Chiller is a solid investment, just make sure you get a solid water pump that can handle the the amount of gallons you are running. A weak pump and a big system is a major pain in the ass and it takes too long to get accurate readings if making pH adjustments. I like a pump that can cycle through all the water in 15 min or so. As long as it doesn’t take longer than 30-45 minutes to cycle the water, I see no real annoyance there.


Excellent information from everyone. (Love this forum!!!)
I will spend the time to really think out the equipment and setup based on your advice.
Thank much all!!! :laughing::sunglasses::v:


I do have another question about temps. With a chiller I can maintain the water temp, but what about ambient temps? For soil the sweet spot is 72-78 for temps.
Is it more flexible for hydro? (Using a chiller)
I have HLG QB 320w lights and they put out some heat. With the larger tent I need to add some light so may generate a fair amount of extra heat. The grow room is usually pretty cool in summer due to central air system.


I still run temps the same but I don’t think 80-81 will be a problem


In hydro the water temp is what is most important. The plant itself can handle pretty high temps as long as the roots and water stay cool.

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Good deal. That’s what I had guessed, but nice to get some confirmation.

I see many systems have bigger intake pipes than the outflow. Is there a reason for that? I imagine bigger intake would keep roots from clogging up, but the overall flow would be limited to the out take diameter and pump strength? I have seen a few using 3/4 inch for both water in and out to res.
What sizes are you using @Vexer @TDubWilly @WickedAle ?

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Im not sure exactly what you are talking about with intake pipes…

Take a look at this, that is a water pump in the ‘rez’

The pipe that connects the buckets has to be bigger than the hose or pipe that delivers water to the buckets.

If it’s not this way, water will not flow back towards your pump as quickly as it should and cause the water level in the plant bucket to rise. You don’t want that.

You want the water level in both buckets to always stay the same

I usually connect buckets with a 1.5" pipe


Basically, you don’t want to feed water into the bucket faster than it can drain out of it.

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perfect thanks TDubWilly!

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My thought was to build this:

The blue lines are from the res to the buckets and the orange lines are coming back. I saw a “negative” pressure set up where the water coming back goes to the chiller then to the res. The shut offs would allow me to size up or down from 2 to 4 or 6. Right now only a thought I am working on.

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I like this guy

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I actually saved this guy’s build!! I did like his approach.

I found this set up which uses the “negative pressure” return. I think they are all similar.

I really appreciate all of your time. This is super helpful. I imagine others can benefit too. :slightly_smiling_face:

Updated my design a bit too.

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After two non recirculating hydro grows, this was the very first one plant recirculating system I built several years ago… this is what you don’t want lol

This caused water levels to be unlevel in each bucket. After I discovered this I quickly changed it to this and it worked well


Cool you totally have helped me see the light!! One redesign coming up!

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