No chiller - sterile RDWC, is it possible?

Hello guys.

This is my third run with RDWC, and now im paying more attention to details i haven't in the previous ones, like trying to keep my roots white.

I choose sterile cause i made an automatic nutes feeding system with arduino and peristaltic pumps. So i just basically do nothing more than changing the water once a week, which takes me 5 minutes, then the nutes and pH go automatic. So making a "tea" is a pain in the ass. Besides, my plan is one day doing this on big scale, and from what i know every big grower use sterile.

Thing is, in my place a chiller is more than expensive and summer is coming...

So i think about adding one peristaltic pump to dose bleach daily and keep bacteria at bay. Temperatures can go as high as 35°C / 95°F.

I know, it is way too high. Despite this, would you think is achievable? The idea is setting up a "x" ml dose every day and then see how roots do. If i see brown roots or i smell, I level up the dose, if a see it is ok, i keep that number.

To do it the professional way, i would have to read the ORP with a sensor like this https://www.dfrobot.com/product-1071.html. But from my understand, ORP is hard to measure in the pH range we use, this is a reason why measuring the residual chlorine is hard to tell in DWC, so we do it "by eye.. and nose".

Has somebody done DWC without chiller and just using bleach / poolshock with success? I'm not interested on bennies experiences.

Thank you guys

shortarker99 said:

Has somebody done DWC without chiller and just using bleach / poolshock with success? I'm not interested on bennies experiences.

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yes.
i would think about dosing at 1 to 2ppm of free chlorine twice a week. autodosing you'll have to worry about stacking the Cl ppms and going from 2ppm to 4 to 6ppm to etc and killing your plants.

I followed @rkymtnman advice on my last grow without a chiller. Pool shock seemed to work well if you stay within the PPM limit. I use a chiller now and still use pool shock once every couple weeks just to keep it clean in there.

If your going to auto dose I would recommend checking the manual way daily and adjusting your auto doser as needed

I ran RDWC without a chiller and had great luck as long as water temps dipped below 70F at least once every 24 hours.

I ran waterfalls which made all the difference in my case.

I did not run any sterilants and in fact didn't do anything more than a quick rinse between runs.

I did not change out the water in the system during the run; I just topped off with more nutrients.

I know this sounds like I broke all the rules, but it worked well and consistently.

I can say that when I first started my waterfall setup my water temps would be 75 without a chiller and I never had a problem, but I never wanted a problem so right around flower is when I started using the pool shock as a preventative measure.

Weekend fun all and happy strains in my mylar tent 4x4 w/th the ts3000 led .

rkymtnman said:

yes.
i would think about dosing at 1 to 2ppm of free chlorine twice a week. autodosing you'll have to worry about stacking the Cl ppms and going from 2ppm to 4 to 6ppm to etc and killing your plants.

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How do you know you are not stacking by manual dosing? i read measuring free chlorine with our ph range is impossible.

Anyway, i will set the autodoser to pump 1ppm twice a week and check the roots every now and again.

Axion42 said:

I can say that when I first started my waterfall setup my water temps would be 75 without a chiller and I never had a problem, but I never wanted a problem so right around flower is when I started using the pool shock as a preventative measure.

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Here in summer, temperatures can go es high as 90°F + pumps + light heat.... waterfall is just nothing

shortarker99 said:

How do you know you are not stacking by manual dosing?

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as you get used to dosing at different ppms, i kinda went by smell. at first like pool water would become weaker and weaker.

for me, i was using it as a preventative so i'd hit it at 3ppm when i did a weekly nute change. then dump the res and start over next week.

Why not try a pond uv sterilizer in your main rez as it will keep the water sterile as it passes through. It wont do shit for your roots just the actual water and nutrients. Now if you go that route you will need to add back some macro nutrients, as the uv breaks them down. I use ionic uv balance. Im not running dwc just drip feed 24/7 and hydroton and my res is squeaky clean.

Here's a pic of what I call hot.. Outside mid July, afternoon..

zypheruk said:

Why not try a pond uv sterilizer in your main rez as it will keep the water sterile as it passes through. It wont do shit for your roots just the actual water and nutrients. Now if you go that route you will need to add back some macro nutrients, as the uv breaks them down. I use ionic uv balance. Im not running dwc just drip feed 24/7 and hydroton and my res is squeaky clean.

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Mainly due to the nutrients fact you named. It is way to impractical, if not impossible to compensate the nutrients broken by the UV. How can you estimate how much nutrients were lost.... I don't want to complicate things.

Edit: I just seen that product "ionic UV balance", I live in a third world country, that stuff doesn't get here, same like aquarium / hydro chillers. And paying a shipping for that is nosense. I will have to work with the bleach

mytwhyt said:

Here's a pic of what I call hot.. Outside mid July, afternoon..

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Did you DWC with those temperatures? how was it? do you go sterile or bennies?

I bought a chiller and keep it sterile.. In the winter I run my WFs with out the chiller.. Just draw the outside air in..

Its possible for sure. You may need to dose a little higher than the normal 1-2ppm or increase the frequency. Tap water can be as high as 5ppm and this is deemed safe for human consumption.

I would also try to insulate your rdwc if you havent already, it helps and is much cheaper than chilling. Just an fyi, use pool shock if its available, not bleach. I say this because shock is usually 65% concentrated where bleach can range from 2% to 12% and its not always noted on the jug. Bleach does work its the unknown factor of the concentration.

I did end up going with the 4x4 grown tent marshydro , I was pretty excited when I setup the tent but may want to go bigger in the future.
I do have a ventilation question though , would a 4” inline fan with charcoal filter move enough air out of the tent or should I be looking at a 6” fan, it’s in an undeveloped basement and I can vent it outside if needed my wife is concerned about any odor. thanks for any nice puts in .

You want a high power with speed controller fan and carbon filter to match. Bigger fan ran slower is quiter if you need that. You need to control the smell simple as.

zypheruk said:

You want a high power with speed controller fan and carbon filter to match. Bigger fan ran slower is quiter if you need that. You need to control the smell simple as.

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6‘’ is just enough or need 8'' fan? i see my bro growroom 4*4 with 6'' fan, i do think it's just enough but not the ideal one , so i would add a larger one then .