Green slimy stuff sticking to roots

oenoveso

Hi Everyone.

I hope to get some tips. I started my system this year and I still can't get the plants to grow healthy. About two weeks ago, I noticed that there was too much green gunk in the water under where the plants are. I read about problems with not enough nitrifying bacteria and I guessed my system had too much ammonia and so the good bacteria wasn't growing and converting the fish poo to nitrogen.

Anyway, I fixed that by cleaning out the plant tanks and replacing the water. I did not completely replace all the water - maybe something like 60% of the total volume was replaced with new water and I also cleaned out the green gunk.

Immediately, I noticed the lettuce plants improve in appearance and quickly grow in size, so I thought my system was on its way to working. However lately, I started seeing problems with green gunk or I think these are algae that are sticking to some of the roots of my lettuce and the outer leaves of my lettuce plants are turning yellowish.

Should I replace the water again? Or just wait it out until enough nitrifying bacteria grow?

Thanks everyone.

dlf_perth

we probably need more information and a photo...
(see instructions here viewforum.php?f=4)

It sounds like you are running a DWC (roots in water with no media ?). In which case DWC and NFT approaches usually require filtered water for two reasons (a) to convert the ammonia and nitrites to nitrates and (b) to filter out the solids.
Hence is typical to have some form of biofilter or filter between the fish tank and beds.
The other aspect is to have good aeration (oxygen) and circulation.

It would be handy if you could actually test your water using a water test kit as that would confirm the ammonia.
Otherwise it could be a bacteria. Sounds like algae and crud.

If it is a media bed then most likely your water level is too high and/or you media too shallow.
And probably not enough media volume...

the pictures would help us provide better feedback.

you may also be overstocked (too many fish)

oenoveso

Hi Darren, thank you so much for the feedback. I'll post pictures tomorrow, I already left for work. I'll try to add more detailed descriptions as well. But from your feedback alone, it sounds like my rafts are floating on too shallow water. my beds are only about 4 inches deep. Should it be like around 12inches?

Also, I don't think I overstocked on my fish. If anything, I probably have too little because there's only about 15 small to medium sized koi in my fish tank. Will too little fish also affect or induce algae and crud? I was worried I would overcrowd the fish.

Lastly, I don't have a filter between the fish tank and the beds. What kind do you recommend.

dlf_perth

> Hi Darren, thank you so much for the feedback. I'll post pictures tomorrow, I already left for work. I'll try to add more detailed descriptions as well. But from your feedback alone, it sounds like my rafts are floating on too shallow water. my beds are only about 4 inches deep. Should it be like around 12inches?

hard call, IMO deeper is better 10-12" and you get better circulation.
You also need a bit of air, but a good circulating system with lots of splash should be fine.

But then systems with 4" pipe (100mm) go well - though they can get clogged up more easily.
These are variously referred to as DWC, SWC, Not-NFT and pipe-o-ponics....
viewtopic.php?f=11&t=29093 (actually worth the read, just got to get over the grumps...)

Usually need to be well filtered in some form.

>> Also, I don't think I overstocked on my fish. If anything, I probably have too little because there's only about 15 small to medium sized koi in my fish tank. Will too little fish also affect or induce algae and crud? I was worried I would overcrowd the fish.

no that should be fine... just added that because you often find out the load is quite large and that equals lots of crud.

>> Lastly, I don't have a filter between the fish tank and the beds. What kind do you recommend.

media beds !! for a small setup going FT -> media bed -> DWC works pretty well and it is a very effective ammonia converter. But that is not always practical.
Other options are drum full of media, radial flow filter and MBBR (search these to get heap of hits).
I would prefer a biofilter in between the FT and DWC...

A good full-on DWC thread to read is Andreas "Crappy Basil Growers are us"... viewtopic.php?f=18&t=16235
The good DWC setups occur from about the middle onwards and he talks about various aspects.

depends on the size of your setup...

oenoveso

Attachment:

File comment: My set-up

hydroponics1.png [ 927.89 KiB | Viewed 1638 times ]

My setup above. I'm thinking now that from what you described, I should move my bucket with gravel to right after the fish tank and before the plant beds.

Below is my gravel bucket.

Attachment:

File comment: My gravel bucket

hydroponics2.png [ 1.26 MiB | Viewed 1638 times ]

And below is a picture of the clearly unhealthy roots.

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hydroponics3.png [ 996.31 KiB | Viewed 1638 times ]

So what I need to do are:

1. Move the gravel bucket to after the fish tank to act as filter
2. Replace my plant tubs with a deeper tanks, maybe 10 inches if I can find the right boxes.
3. Replace all my plants.

Darren, do let me know if you have other ideas you think I should try. I'll work on this and report back how it goes.

dlf_perth

OK, so tub based DWC..... these do tend to get a bit dirty.
Try and get some deeper tubs - at least 250-350mm (10-12")

(a) go for 1 tub as a media bed. You can plant things in that. Then feed the DWC tub.

or go with a large bucket (5-10Gal) full of media, the rock you have is fine.
the best option is to feed a pipe down to bottom and then have water spilling over top
ie. flowing upwards. This will keep the water-head in your setup.
put a tap at bottom and you can easily drain off the crud and use it to feed pot plants etc.

(b) go to a solid cover over the tubs (air gap method), then don't have to worry about the rafts.
the plants should benefit from this.

(c) make sure the flow through the DWC tub is good. You are getting trapped crud.
one option is to pour filtered water in at the top and use a SLO outlet pipe
so you are taking stuff away from the bottom of the tub.

(d) if you want you could make a small biofilter *but* in such a small setup a media bed will be most effective.

dlf_perth

the other negative is that your tubs look translucent / semi-clear and that will encourage algal growth.

While DWC looks useful for little systems like this you will get just as much growth from a media filled tub system.
The benefits of DWC are not really achieved at this scale whereas media bio-filters will also provide opportunity for solids retention and mineralisation.

what are the dimensions of the tubs ?

I also presume your pump is in the second tub ?
(not a bad thing as your fish tank then cannot be drained out)

>> I should move my bucket with gravel to right after the fish tank and before the plant beds

yep, it would benefit from being immediately after the fish tank.
Three or four buckets like that filled up with more with media could work.

Also those media buckets would gather a lot more solids which (provided you have enough volume) the tomato? plants will actually benefit from as the solids break down in the media over time.

SebZ

+1 for the translucent containers. Cover them with black plastic sheet for example.
Everything except the plants should be protected from light (fish Tank, piping, DWC containers).
And plant roots shouldn't be exposed to light.

oenoveso

SebZ wrote:

+1 for the translucent containers. Cover them with black plastic sheet for example.
Everything except the plants should be protected from light (fish Tank, piping, DWC containers).
And plant roots shouldn't be exposed to light.

Thanks! Yes, I'll upgrade my setup and make sure to use opaque plastic or cover it up with a dark material.

I like your very neat setup here viewtopic.php?f=18&t=25794
. Once I feel confident and start actually harvesting from my small set-up, I plan to build a bigger, neater and more permanent setup.

oenoveso

dlf_perth wrote:

OK, so tub based DWC..... these do tend to get a bit dirty.
Try and get some deeper tubs - at least 250-350mm (10-12")

(a) go for 1 tub as a media bed. You can plant things in that. Then feed the DWC tub.

or go with a large bucket (5-10Gal) full of media, the rock you have is fine.
the best option is to feed a pipe down to bottom and then have water spilling over top
ie. flowing upwards. This will keep the water-head in your setup.
put a tap at bottom and you can easily drain off the crud and use it to feed pot plants etc.

(b) go to a solid cover over the tubs (air gap method), then don't have to worry about the rafts.
the plants should benefit from this.

(c) make sure the flow through the DWC tub is good. You are getting trapped crud.
one option is to pour filtered water in at the top and use a SLO outlet pipe
so you are taking stuff away from the bottom of the tub.

(d) if you want you could make a small biofilter *but* in such a small setup a media bed will be most effective.

Thanks Darren, these ideas/options really help. I'll redesign and rebuild my system from these inputs. I'm curious about the solid cover over the tubs that you suggested. I'll read up on that. I think I might do exactly that. I'll read up also on SLO outlet pipes for my tubs and do that as well.

I'll follow your suggestion also on having one tub as a media bed. I don't know how fast I can finish the improvements though as I only have weekends to work on this but I'll post updates.

dlf_perth

that is what I use... acrylic double wall roofing sheet with a blue 60 Litre tub.
Was a temporary when I was between setups just to keep things ticking over.
The media tub was 100 Litres (~25 Gallon)

The white pipe and ball valve (tap) at bottom left of the media tub allowed me to drain off all the crap.
Which went straight into a bucket and on to my wicking beds and on my fruit trees...excellent..
(the pipe twists to face out when draining the tub, just kept it pointing inwards when not in use)

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If you don't have media tubs go with the buckets - a cluster of 3 or 4 would do the job.
But fill them all the way up with media.

dlf_perth

this is it growing baby spinach, also used it for lettuce over summer.
And grew water cress in the media tub... and also spring onions..

I find the airgap method with larger baskets (80mm or 3") of clay media is pretty effective.
And the media tub does a good job of filtering...
the water level sits about midway down the basket and the clay balls stay moist.
The acrylic roofing just sits on top of the tub.

oenoveso

Hi Darren, thanks for sharing this. The pictures really help. This looks like what I'll be going for. I can source the material pretty easy. Question though, is that a bell siphon in your media bed? or is that just a normal drain/outlet where the water exits and goes on to the tub?

Also, how often do you drain crap from your media tub? Once a month or so?

I'm surprised with how close the holes are to each other, but the plants still seem really healthy and leafy. I was wondering how much the lack of space would affect plant growth. Apparently, not much at all looking at your greens in your setup.

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