Need some advice - DWC root issues?

Hello folks,

In my first attempt at DWC I have discovered what looks like root slime last night. I need some help to identify the potential cause and treatment plan. Pictures below.

Conditions before slime:
pH 5.8
Green Planet nutrients
68-70F temperature
EC around 0.9

Conditions when noticed slime:
pH 6.2 (drifted UP, not down as indicative of bacterial growth)
68-70F temp
EC around 1.3-1.4

Roots are brown-ish but I read that MC will do that. Last night i got home late from a business trip and immediately treated the rez (66L) with about 0.5g of HTH 47% pool shock. Pictures below from after the treatment.

Slime does not smell bad. Root tips/outsides do not pull off easily, Plants look healthy. Not sure if new root growth is present, I did not pay attention. The slime is concentrated in the knots that the roots form when the bubbles get them all tangled.

The 4x DWC buckets are fed with a 20W Danner pump, one XL airstone each (5 true watts per bucket, plus another 5W pump in the rez)

Recirc rate is pretty slow at about 230L(60G)/hr

This is what the roots look like. The slime is in the knot in focus.

This is what the plant looks like:

Any thoughts/ideas very much appreciated.

The only big change was going from green planet nutrients to megacrop. I do not want to blame the nutrient if I did something wrong though.

EDIT: This is what the roots looked like before:

You were wondering about slime build-up?

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Is that the culprit?

It would not be the first time I have heard the name in the same thread with complaints of sediment build up.

I am in soil, so, I wouldn’t know. But if I had additional sediment to worry about, it wouldn’t help my soil situation either, so, I have I avoided it.


In hydro myself using mega crop and my roots are brilliant white with no slime. I do use a little pool shock in the rez though as a prevention for root rot. What temperature is the solution that the roots are sitting in? Alge thrives in temperatures above 65 degrees. :+1:


Your temperatures appear to be in a safe zone. Recirculation of 60 gallons/hour. How many cycles is that for your system capacity? Aeration looks ok?

There are a couple of descriptions of the sediment, I think 99 is referring to, in the Greenleaf nutrients thread. Not certain if that is the same thing as the slime you are seeing here.

This “might” be helpful (RIU),


Interesting thread. The main culprit in that thread seem to be the type of PH down. Anything organic, like vinegar or citric acid, was a problem. No mention of nutes being an issue.


Yes, I’m not certain what to make of that solution yet. Bacterial bloom due to the organics + somewhat anaerobic conditions? The solution was a bit unexpected in that case.

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Thanks folks, it does seem odd. When i put the megacrop in I dosed with h2o2. Afterwards I did put pool shock in at a good rate.

My pH down is phosphoric acid. I think I will dump the rez, flush with ph adjusted h20 and refill with GP nutes, then reassess.

The pH creep is odd. So far after the initial adjustment and maybe a tad more after 24 hrs it has held steady for about a week. This water though is needing daily adjustment. It drifts up to 6.2 or so reliably every 36 hours.

Plants are fine though, so I am starting to wonder if it is par for the course with MC?

@Esrgood4u, are you in dwc as well, or other hydro?


How often do you change out the rez?

The PH creep could be from the slime/pathogen or a nute imbalance in the rez. Your EC at 1.3-1.4 is in a very good range I would think, so I doubt its EC/nute related. Still, your idea to switch nutes as a test is a good one.

I cant think of anything else as a likely suspect. Do the test and at worst, you at least eliminate one possibility.


I’m using bubble buckets. When I first started them off I had a slight algae problem that I traced to light getting into the root zone. Masses of duct tape fixed my problem for me. I use pool shock as a preventative “just incase”. I never do water changes unless the plants are suffering in some way. I check the ec and ph in the buckets then mix up a solution that takes it to the ec I’m aiming for, top them up then adjust the ph if its needed. I add about 5ml of my pool shock solution directly into the buckets once a week.


Your ph should slightly creep up anyway and in an ideal world your ec should remain stable as the plants feed.


@Larry3215, I kept the solution for 2 weeks when they were babies because it didnt move in any metrics. This current water is only a couple of days old.

I figured I’d change when the ph is hard to keep in check, no set time.

Going down to the basement right now and going to flush the system…


The system is 66l/16g roughly so pretty good turnover

I found evidence. Green, nasty, pond-worthy globs of growing algae evidence

It was growing where water flow was laminar

I mechanically removed as much as I could and then bleached the living fuck out of the system with a concentration that is incompatible with life. I want no DNA in those buckets, except for the ones I put there…

Then refilled, shocked, and put the plants back. The basement smells like the mechanical room of a swimming pool.

I’ll update how they do


@Esrgood4u some of my fittings are white, I’m gonna aluminum-tape the shit out of those too


Yeah light getting into the roots can cause the problems your having :+1: and don’t be afraid to use chlorine with your plants. Chlorine is a micro nutrient that plants can benefit from. I don’t understand why people try to dechloronate there water.


How much chlorine do you run? I have heard varying numbers from 1 to 200ppm free chlorine…


I didn’t go the ppm route. I mixed 2 gram of pool shock with 2 liters of water then I use 5ml of that solution in my 3 gallon (uk gallon scale) bubble buckets once per week. It’s a really really diluted amount.


Yeah that is quite a bit more diluted than the treatment i gave my system last night. Right now I have 0.5g in 66L. Plants dont seem to care one bit - this is about 5 min ago.

No more slime on the roots. Some debris but it looks very dead and just hanging out. Couple more rez changes and it should be gone.

Thanks for your help @Esrgood4u, @Northern_Loki, @Larry3215, @99PerCent!


I’m sure it will be fine. Any light leak will help algae thrive so you did right covering the opaque fitments. To be honest I now think that has been your main issue. Anyways keep us updated on how they progress :+1: