Creating a RDWC Setup - Could use some Pointers

Joint Monster said:

@dstroy Looks good mate!



Could you explain why you say that? (Most of what I've been reading seems to concur it is better for the chiller to be run in it's own loop.)

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It's going to cool the same amount of water regardless of if you do two loops or not, that's just another pump to warm up the water imo.

Ahh okay I see. I'm still trying to put things together, but I was reading someone who had a chiller inline, was having specs coming out of their chiller after they tried cleaning it (nutrient build-up / salts). I'd rather another pump and by-pass any possible trouble with a rather pricey unit. I just wanted to know your reasoning.


I found this in the ActiveAqua Manual, which is rather interesting. It implies it is meant to be run inline. It also says not to use soap, and to go with a hydroponic flushing product. (But I guess that's different that using one drop of soap as a surfactant?)

https://www.hydrofarm.com/downloads/fc/Active Aqua Chiller_12777.pdf

Cleaning and Maintenance:

Flushing of the internal chiller components is recommended at least once every 1‐2 months to ensure optimum performance and efficiency. Overtime, nutrient deposits and other debris may accumulate inside the chiller impeding the operability.

Note: Do NOT use soap or detergents for cleaning the internal components of the chiller system.

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Joint Monster said:

Ahh okay I see. I'm still trying to put things together, but I was reading someone who had a chiller inline, was having specs coming out of their chiller after they tried cleaning it (nutrient build-up / salts). I'd rather another pump and by-pass any possible trouble with a rather pricey unit. I just wanted to know your reasoning.


I found this in the ActiveAqua Manual, which is rather interesting. It implies it is meant to be run inline. It also says not to use soap, and to go with a hydroponic flushing product. (But I guess that's different that using one drop of soap as a surfactant?)

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It doesn’t have to be ran inline, and a drop or two of soap in fifteen gallons of coolant is not enough to do anything except decrease surface tension. The pumps do heat the water, but you’ve got one large one running for the chiller anyway. The smaller pumps for the immersion coils are like 20w which is nothing.

The real downsides of closed loop is the added space required, additional cost and complexity, and that’s it.

The upsides are less maintenance, no nutrient solution gets pumped through the chiller, therefore it will never have any salt buildup that needs to be cleaned, and lines to and from the chiller can never get clogged with biofilm.

dstroy said:

I don't run RDWC but I do have a chiller set up and has been running for about a year.

I use that rubber a/c pipe insulation on the coolant lines too, works really well. Side bonus is that it stops condensation from forming. I was surprised that so many people were running nutrient solution through their chillers instead of doing a closed loop, because they're not exactly cheap. From an equipment maintenance standpoint alone it makes the most sense to use closed loop.

I also like to put a drop or two of dawn in the coolant res for a surfactant. Doing that makes the entire system more efficient. Can't do that with an open loop design. Don't use distilled water by itself.

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What do you use your chiller for? Hour big is it?

I used mine for HVAC, dehuey, cooling lights and chilling my RDWC- but I had a big one... 5 Ton lol

ttystikk said:

What do you use your chiller for? Hour big is it?

I used mine for HVAC, dehuey, cooling lights and chilling my RDWC- but I had a big one... 5 Ton lol

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Just a little 1/10hp. I’ve only got 1100w of Cree leds, but the ones in the veg tent are always dimmed to 50-60% so more like 800w. I only use mine to chill coolant and nutrient solution.

My setup is small potatoes, just 60 something gallons total water being chilled, my main reservoir and chiller res are kept at 68f, and I restrict flow through the coil I have in my cloner to keep temps a bit higher at 72f.

When I was in the navy I worked on some pretty big chillers that were required by the equipment I worked on. Those were also liquid-liquid, can’t be pumping seawater through electronics.

MeGaKiLlErMaN said:

Inline, the only way to go.

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No.

dstroy said:

Just a little 1/10hp. I’ve only got 1100w of Cree leds, but the ones in the veg tent are always dimmed to 50-60% so more like 800w. I only use mine to chill coolant and nutrient solution.

My setup is small potatoes, just 60 something gallons total water being chilled, my main reservoir and chiller res are kept at 68f, and I restrict flow through the coil I have in my cloner to keep temps a bit higher at 72f.

When I was in the navy I worked on some pretty big chillers that were required by the equipment I worked on. Those were also liquid-liquid, can’t be pumping seawater through electronics.

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But if you aren't running RDWC what's being cooled?

Here's a pic under the hood of my 5 Ton dual circuit chiller from ChillKing;

ttystikk said:

But if you aren't running RDWC what's being cooled?

Here's a pic under the hood of my 5 Ton dual circuit chiller from ChillKing;
View attachment 4045808

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Neat, I like industrial control boxes. Always so tidy.

I still have nutrient solution to cool, just around 60 gallons to 68f. so you know.... next to nothing. Hence the 1/10hp lol

I’m just a hobbyist, not like a major grow op. No need for me to have a piece of equipment like that yet, but I’d totally utilize it for dehumidification, to cool the air, and to chill nutrient solution.

ttystikk said:

No.

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Unless you're cooling your while room why not?

Two pumps is what you would choose?

MeGaKiLlErMaN said:

Unless you're cooling your while room why not?

Two pumps is what you would choose?

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Don’t know if you’ve tried yet but you can’t really get inside of the smaller chillers to scrub them out. So then it eventually becomes a reservoir for bacteria, and everything else that lives in your nutrient solution with no real way to clean it other than a “flushing agent”. After several years of it running, it becomes less efficient due to biofilm buildup because that stuff doesn’t come off unless you scrub it (I know from years of experience of cleaning out pipes hehe). Seawater pipes.

If you look at industrial heat exchangers, they will always have a dedicated clean side, where only “clean” coolant gets pumped through. The heat exchangers I worked with were like that. We had to take them apart and clean them quarterly, or they didn’t work as designed.

Anyways, for me, the entire reason to have separate loops was to cut down on maintenance and prolong the life of my chiller. If I was constrained on space I would do it differently, or possibly move that equipment to another room and just pump the chiller water into the grow room.

I am going to get a larger chiller, and use that to cool my tents as well as chill my reservoir so it’s nice to see someone implementing that in practice @ttystikk . I want to seal up my room so I can start using CO2 at some point, though I will not need quite as big of a chiller as you.

There are valid reasons to do it either way, every situation is unique and careful consideration of all options will prevent headaches. It does help to lay out the pros and cons for each setup before implementing it.

dstroy said:

Neat, I like industrial control boxes. Always so tidy.

I still have nutrient solution to cool, just around 60 gallons to 68f. so you know.... next to nothing. Hence the 1/10hp lol

I’m just a hobbyist, not like a major grow op. No need for me to have a piece of equipment like that yet, but I’d totally utilize it for dehumidification, to cool the air, and to chill nutrient solution.

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I used water cooled air handlers. RH is managed by the temperature of the water in the cooling circuit. Another cooling circuit goes to a water to water heat exchanger in the RDWC control bucket.

Each of these individual circuits has their own valve to isolate them from the rest of the system to make reconfiguration a snap.

The hot side is similar, passes water through a coil in the hot water tank and through a water to air heat exchanger core in a bigger air handling unit for heating the house. A similar core plumbed to the cold water side does Central AC all summer.

The nice thing about water chilling is that getting a unit with excess capacity doesn't create extra running costs.

Y'all should see what I'm up to on the water cooled LED front, but that's going to have to wait a bit.

Of course, if you ever come out to Colorado, I might arrange a private show n tell for ya!

MeGaKiLlErMaN said:

Unless you're cooling your while room why not?

Two pumps is what you would choose?

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@dstroy answered this question very well.

ttystikk said:

@dstroy answered this question very well.

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That's fair, I suppose I under value the lifetime putting bites through it. I don't run a sterial environment and have a lot of beneficials in it. Making it like a nute rich compost tea. Also running the dual root zones to see if they mak a difference in root mass

@dstory put it really well! Thanks for your wisdom! You really convinced me to do the separate loop, and I feel like you saved me from a big headache down the road.

I ended up going with a 50Ft Wort, 1/4HP chiller, and the minimum recommend gph pump for that chiller which was like 220gph. (That pump was recommended for a 15gal. res so that should work perfect.)

ttystikk that's one big system! I like the wiring, super neat and tidy!


I was looking into the Piping, hygrohybrid just did a simple 4" pvc at the bottom running in a circle.
>I saw this system which seems really interested... they also have one more smaller pipe going from the bottom to the middle of each container (right about under the net pot line it looks like). Is this something worth looking into? It seems like it would add better water flow, and if something happens to clog below it should still keep things going nicely.
>They also have another return line going from the bottom piping to the reservoir. Is there a good purpose to adding a return line, versus just doing one big circle pvc like hygrohybrid's build?

I'm having trouble finding "Food-safe" or "Hydroponic" Totes for my containers. I was hoping something between 20-35Gallon container size that is food safe but I can not seem to find anything. If anyone knows of anything/brand that'd be awesome!
>I'm also now debating using PVC piping......

Also can someone confirm this, for a waterfall / to recirculate the water, you want in general, 12 circulations per hour? So.......
>Your Systems Total Size in Gallons x 12 = gph pump you need

I can get 12Gallon Cooler for about $20.. Considering using them as containers instead, just worried they might be a little small.