Please help - first time grower experiencing root rot each time DWC reservoir is changed

Hi all,

I apologize in advance for the extremely lengthy post. And I did scour all forums (this and others), books, etc. as much as humanly possible before creating this post. I don't want to be one of those lazy people just asking questions when the answers can easily be found.

I'm a first time poster, so please forgive me if I'm not posting in the correct location or if I'm doing anything else stupid in regards to forum etiquette. Please tell me what I'm doing wrong...I won't take any offense.

I'm currently at day 30 of my first grow. I'm experiencing mostly good growth and overall health with some pretty significant hiccups along the way. I'm hoping those more experienced can help me before it's too late.

My setup:
I'm in a Supercloset Deluxe 3.0 running a Kind LED K3 - L450 with a 15 gallon DWC reservoir (Superponics 16, I think it's called). I'm using the Technaflora nutes that came with the closet package. They call it the "Recipe for Success" but I'm not so sure. I plan on changing my nute program next time around, but that's a topic for another day.

After germination and moving the babies "upstairs" into the veg/flower chamber, I started with 25% of the suggested nutrient levels. I have, over the course of three weeks increased my levels to 65%, having done a step by step increase on each reservoir change (started at 25%, then 40%, and now 65% as of yesterday).

My current stats:
Ambient air temp - 77 F (goes up and down a couple degrees over the course of the day)
Water temp - 66 F (I installed a chiller after my last scare with pythium)
PPM - 860
pH - 6.8
Relative humidity - ranges from 45-51% depending on time of day in relation to lights on/off

I have successfully germinated 10 seeds only to realize after the fact that I should probably only keep 2-5 of them in order to have enough space for the stretch and flower. I plan on culling all but a couple/few biggest soon, but I was hoping to get through this second reservoir change before doing so. The reason being is that each time I change my reservoir, I introduce the beginning stages of root rot. I'm certain that I'm not just observing a discoloration of the roots due to adding nutes, though I do have some of this as well.

Last time I got root rot, I reacted in two ways to address the issue...
1) I added Hydroguard. Over the course of several days, the roots were showing new white growth. For this reason, when I mixed my 65% nutes yesterday, I added Hydroguard as a preventative. NO LUCK!
2) I installed a chiller rather than dealing with ice bottles which I was concerned was likely causing shock due to the extreme cold when first placed in the reservoir. Also, I was never able to keep a constant temp with the ice bottles. The chiller does the trick nicely.

I'm once again at the beginning stages of root rot and in a bit of a panic. As I mentioned above, I used Hydroguard yesterday after mixing all of my nutes. I did this as a preventative measure and it didn't do the trick.

I also added SM-90. I know there's a ton of conflicting information out there on whether or not SM-90 can be used in conjunction with Hydroguard or anything else with beneficial bacteria. I ultimately decided there was a fair amount of disinformation in regards to the topic. Supposedly the company has produced tests showing that SM-90 does not impact beneficial bacteria. This could have been a big mistake?

I suppose my hunch is that I'm doing something wrong when doing the actual reservoir change. The process I follow is essentially:

- turn off and raise LED
- turn off inline pump to chiller
- raise top of the DWC lid (I've done this by installing a pulley system so that I can lift the lid straight up and out of the way
- siphon old soup out
- clean reservoir with H202, removing as much buildup as possible, though I haven't had a ton of "scum"
- siphon new water (I'm using deionized which is similar to distilled) into the reservoir
- mix in nutes as per instructions
- add in Hydroguard in amounts as per instructions
- add in SM-90 in amounts as per instructions
- correct pH (though this soup has almost always been right at my pH target)
- lowering lid back into place, ensuring roots make it back into water without getting stuck on any of the tubing in the reservoir
- lower and turn on LED

I am able to achieve all of this in less than 45 minutes, and my roots are out of the water for less than 30 minutes (am I killing my roots with a half hour air bath?).

As an aside, can I (should I) add Hydroguard or SM-90 to the reservoir again today to address the problem? I'm worried about using either product too frequently.

Again, sorry for the stupidly long post. I just wanted to included as much information as possible to help with diagnosis.

I truly and sincerely appreciate any help that can be offered.

I ran dwc a few year and your hunch is right imo the 30 min airbath is drying and killing the roots
I made the same mistakes ifound rep ways around this
1 keep the root mass in the sealed / humid bucket when canging res just install a tap on the bottom of dwc res
The humidity trapped in the bucket is enough to keep them moist whilst it refils
2 have another bucket of water to place the plant in whilst changing

I noticed in 5 min in open air pulpous healthy white roots would start thin and brown slightly from the air

Hope this helps

Makka, thank you so much for getting back to me!

I will certainly figure out a way to minimize/eliminate the air bath duration for my next reservoir change.

For now, how do you think I should go about rectifying the root rot? Can I add more Hydroguard or SM-90 today? Or do I have to wait "x" number of days since I added it yesterday?

I'm not familiar with them products tbh so I can't say sorry
I use to use h2o2 as a preventative but ran a sterile res no bennies or organic just chemical

Thanks again, Makka, for getting back to me. I really appreciate it!

you need to butt and stabalize your water then ph it then add nutes and keep it ph`d bubbling for a few days

If you want to do a direct re-fill if your last res was stable keep 10 to 40% of it this helps with the micro biology of the new res

then ph a bit lower

for the next 2 to 6 days you have to ph like a mofo fresh water and a fresh res are very unstable unless your using Hydrogen peroxide or pool shock or something

I use "water butt fresh" treatment and trichoderma but I just butt my water these days and use large coco sacks not ran dwc for a couple of years now

Kinda miss it like not having to use coco just getting my "soil" from the tap

if your using distilled water you may want to add extra buffers I find in flower extra PK in the res can help stabilize PH longer, also using Silicon to raise the ph and then a mixture of ph down acids to bring it down work

I go for ph5 and let it swing up to a max of 6.5 before dropping back down, somewhere between 4.8 and 5.8 seems to work best for me but not so many people agree with that depends on your nutes and the strain I guess

Water fall`s and bubblers help

also a filter can help skim the scum off the water if your having issues with that

Thanks Konassure!

I do have to make a correction to my original post. I'm at 5.8, not 6.8. And I've been holding steady at 5.8 almost my entire grow. Once in a blue moon I've reached 6.0, but that's the highest.

So the idea behind water butt (this is a brand new term to me) is that I keep some of the previous water in the reservoir to help stabilize things? Or have I misunderstood?

TimeIsDancing said:

Thanks Konassure!

I do have to make a correction to my original post. I'm at 5.8, not 6.8. And I've been holding steady at 5.8 almost my entire grow. Once in a blue moon I've reached 6.0, but that's the highest.

So the idea behind water butt (this is a brand new term to me) is that I keep some of the previous water in the reservoir to help stabilize things? Or have I misunderstood?

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I would tend to think he is talking about like when you change a fish tank's water and you leave a % of the old water.

I think from a glance you need more bubles or o2 in the water. Last time I ran DWC I had issues under 6.2 PH.
Te root rot will clear up if you add more bubbles and hydroguard and keep temps low. Destroy the environment RR needs and it cant thrive.
#Random

Thanks Cx2H!

I will definitely leave some of the reservoir water on my next change out to help stabilize the microbiology as suggested by Konassure.

The weird thing about my situation is that this happens each time I change the res. Over the course of the next 7-10 days, I'm able to help the roots rebound sufficiently so they look nice and white again. So, I do think my water temp and disolved O2 is sufficient, or else I wouldn't be able to see white root growth. Or am I wrong about that?

I think I'm doing something wrong when I change the res. I do believe the stasis environment (pH, res temp, air temp, humidity, etc.) are all in check. Though, as a new grower, maybe I'm wrong? My stats are as follows...

Ambient air temp - 77 F (goes up and down a couple degrees over the course of the day)
Water temp - 66 F (chiller installed)
PPM - 860
pH - 5.8
Relative humidity - ranges from 45-51% depending on time of day in relation to lights on/off

Do you think I should raise the pH? You mentioned that you experienced issues below 6.2

Thanks again!

TimeIsDancing said:

Thanks Cx2H!

I will definitely leave some of the reservoir water on my next change out to help stabilize the microbiology as suggested by Konassure.

The weird thing about my situation is that this happens each time I change the res. Over the course of the next 7-10 days, I'm able to help the roots rebound sufficiently so they look nice and white again. So, I do think my water temp and disolved O2 is sufficient, or else I wouldn't be able to see white root growth. Or am I wrong about that?

I think I'm doing something wrong when I change the res. I do believe the stasis environment (pH, res temp, air temp, humidity, etc.) are all in check. Though, as a new grower, maybe I'm wrong? My stats are as follows...

Ambient air temp - 77 F (goes up and down a couple degrees over the course of the day)
Water temp - 66 F (chiller installed)
PPM - 860
pH - 5.8
Relative humidity - ranges from 45-51% depending on time of day in relation to lights on/off

Do you think I should raise the pH? You mentioned that you experienced issues below 6.2

Thanks again!

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"Root rot can have two sources — one is a prolonged exposure to overwatered conditions that can cause some of the roots to die back due to a lack of oxygen. As they die, they can start to decay or rot away. The rot can then spread to healthier roots and kill them as well, even if the soil conditions are corrected. The other source can be from a fungus in the soil. The fungus may lay dormant in soil indefinitely and then may suddenly flourish when the plant is overwatered once or twice. The root rot fungus attacks the roots and causes them to die and rot away."

"A major threat to plants grown hydroponically, both indoor and outdoor is a “root rot”. As the name suggests, it's a condition where the roots tend to rot due to over exposure to water. Bacteria, fungi, and mold invade the roots under such damp conditions and cause them to rot."

Me I would h2o2, run 6.2 and bubble the sheet out of the buckets (bubbles is a way to control ph as well). RR is caused in my experience from not enough bubbles in the root zone or if in those pvc tube things water moving fast enough. Just a thought.

I'm running into the same issue.. and I have almost the same setup same elements, and I believe this cx has the right point id like to add I've learned root rot also comes from standing water, and I've had fish before so I did this 20% keeping old water thing and it didn't help me much, I believe it's a pump we are missing to circulate water if I think about a fish tank bubbles are no good for 10gal or more tanks.. hence why I said same setup my bins are 15gal too and I had less problems in my 5 containers minus more ph fluctuations, I'm gunna try pumps and let you know how it changes things for me, I hear h202 too but I also hear and see why bennies are soon good and they thrive in moving water pythium lives in standing water.. fishtank pumps are even per size of tank the flow of water I believe is the key missing thing here.
Please anyone correct me if I am wrong I haven't much experience myself about 4 grows indoor 2 of which are dwc.

Bbk23 said:

I'm running into the same issue.. and I have almost the same setup same elements, and I believe this cx has the right point id like to add I've learned root rot also comes from standing water, and I've had fish before so I did this 20% keeping old water thing and it didn't help me much, I believe it's a pump we are missing to circulate water if I think about a fish tank bubbles are no good for 10gal or more tanks.. hence why I said same setup my bins are 15gal too and I had less problems in my 5 containers minus more ph fluctuations, I'm gunna try pumps and let you know how it changes things for me, I hear h202 too but I also hear and see why bennies are soon good and they thrive in moving water pythium lives in standing water.. fishtank pumps are even per size of tank the flow of water I believe is the key missing thing here.
Please anyone correct me if I am wrong I haven't much experience myself about 4 grows indoor 2 of which are dwc.

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Dude - the newest comment on this post was almost 6 years ago. Start a thread. Include pictures in normal light.

At least he used the search bar