Backyard Aquaponics
A place to discuss aquaponics

Good day Aquaponikers

Been running with issues of root rot/debris or pathogen(?) overwhelming my crops in DWC.

Notes on system:
1. Radial filter does a good job. FT and sump water is pretty clear.
2. Media bed crops have been doing well.

Currently picking my brain on:
1. how I can further filter debris getting into dwc
2. Is there not enough dissolved oxygen?
3. I've rotated the 20mm inlet pipe in the picture so you may get an idea of the flow rate. I believe the flow rate is adequate
4. Should radial filter be cleaned out more often?
5. I haven't cleaned the raft bed since Nov 2019, and the sediment accumulation is very fine
6. Removing all cococoir (for wicking action) from netpots

Any help would be much appreciated

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Where is the RFF located in the flow loop?... Is it immediately prior to the DWC bed, or elsewhere in the flow loop?... How old is the plant in the pic of the root system?... What type of plants and how long are they staying in the DWC system?... What has the water temp been getting mid-afternoon on hot days?

Hey Mr Damage :p
Where is the RFF located in the flow loop?
Right before Raft bed, then comes media bed

How old is the plant in the pic of the root system?
1 and a half month

What type of plants and how long are they staying in the DWC system?
Bok choy,lettuce and basil but I haven't gotten any pass the size of my palm

What has the water temp been getting mid-afternoon on hot days?
I haven't taken a reading as I just got a thermometer but still cool to the touch. Like a pleasant pool water

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In the first pic it's pretty obvious it needs a clean.When the air starts bubbling up from the air stones,all of that coco hair powder is going to go up with the bubbles and cling to the roots.


The media bed is after the DWC bed?

You haven't mentioned how many fish you have,how big the system is, what the Nitrate is reading & what you are feeding the fish.All of that could be playing a role in why the plants aren't doing too well (lacking nutrients).

If you wanted to add an extra filter for the fines,you could add a sand filter after the RFF.

Hello and welcome to the forum

If your using a half blue barrel as a DWC its not really deep enough (roots on bottom surface)

As stated above the air stone will be disturbing the bottom sediment

Lift air stone up halfway or remove

I think you could slow your flow quite a bit try a third of that flow

Turn your DWC volume over every hour at a maximum

A half IBC is a good option for a little DWC "DEEP Water Culture"

Water coming in needs to be as clean as you can get it

Ive even used Socks to trap particles after cleaning out media beds of plants (lots of root fragments)

Lots of options

Keep the Pics and questions coming

Have Fun

I really appreciate all your feedback guys. What you guys share makes a lot of sense.
Terra that's a beautiful setup you have. Btw, doesnt algae bloom between the ridges of your ibc tank and your styrofoam?

To answer your questions:

You haven't mentioned how many fish you have: 22 tilapias about the size of a guy's palm so non juvenile

how big the system is: the system is made of 200L barrels. FT is close to 200L, Sump is about 120L, raft bed is half a barrel, and media bed the other half. Media is 1/2 in ashphalt rocks

what the Nitrate is reading: 160ppm

pH:6.0

& what you are feeding the fish: koi spirulina feed (not cheap )

All of that could be playing a role in why the plants aren't doing too well (lacking nutrients).

If you wanted to add an extra filter for the fines,you could add a sand filter after the RFF.

I think the next step is to do a thorough clean up, add a filter consisting of a perforated container with aquarium sponge filter and sunshade (?), and as Terra suggested, decrease flow, and raise airstones.

Should I have designed it with media bed right after RFF? Murray says it makes a difference. I don't see why bc mine is plumbed so that pump tees into dwc and media bed? Do the particulates enter the first canal of egress(which would be to the raft)?

I read about a fairly large scale running raft systems without any filters. He said it all came down to quality fish food and not over feeding shrug

If your nitrate is in the 160ppm range it could easily be much higher dilute with rain or distilled water and retest to get a more accurate guesstimate .

Long term try for 20 to 40ppm , high nitrate messes with plants , overgrown sappy growth that every bug in the world loves

Any nutrient in excess will trigger deficiency in something else , so its a case of more is not necessarily better

With regards to large raft systems with no filters anything is possible if you have 10 fish and a ten thousand litre raft that was 500mm deep it would work fine for some plants

All the waste would settle and could be vacuumed out regularly

We can grow leafy greens on very little nutrient however fruiting plants need a lot more

For a aquaponic system to work we need enough SURFACE area (tank walls , media , pipe surface ect ect ) for bacteria to colonise to handle the ammonia being produced so Surface area / fish numbers / feeding rates / plant type need to be in balance just to make it more interesting we have seasons which gives us temperature and light variations as well.

Learning all this is a big part of running our systems and managing the plant rotation

Usual sequence is Fish tank / RFF / Media Bed / Raft / Sump / Return to fish tank

This however would create too much flow through your raft , for this to work all the components need to be sized correctly eg ldeal would be raft volume twice the size of your fish tank or more.

Can you go Fish tank / RFF / then split to 2 media beds one constant flood and one siphon / then constant flood bed (slow flow) through a small settling container with maybe some shade cloth scraps in it (easy to clean) then through your raft and on to sump.

The other "Siphon bed" (which could be constant flood as well) goes straight to the sump and can handle more of the pump flow.

This would clean your water up

Keep working away at it until you get your plant roots nice and white

The raft in my pic was from awhile ago I just ran a couple of yabbies (like large shrimps)in the IBC which cleaned up the sides and I had no trouble , I learned the hard way to not plant so close ended up a jungle with all the brassicas , of course they can grow in there for awhile then put them in a media bed .

Growing advanced plants is another good practice to maximise the return from our grow bed space

Cheers Terra

Wow Terra, you're just a wealth of information. How long have you been practicing aquaponics for? You are running a serious system!

I appreciate you taking the time to write and help as I don't know where I would be getting all this info otherwise. I take a lot of valuable info that I need to learn and practice from what you share. Thanks!

Are you an advocate of CHOP 1 systems? I was under the impression that CHOP 2 was the way to go for optimal flow control instead of tweaking with gravity? Perhaps I'm not understanding correctly...Could you please have a look at the attached picture ?

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Ive been thrashing around with AP for 8yrs now

Been a member of the forum since 2007 and lurked and read alot before I built anything was just too busy with other hobbies.

I come and go a bit , forum has gone quiet compared to a few yrs ago a lot of people seem to go to YouTube now unfortunately you can pick up bad habits there very easily , lots of really good info stored in this forum , use search function

Not much has changed here recently as I had a m/cycle accident which knocked me around for a 18mths (limited use of left arm and no spare $$$)

Soon I hope to move my system around the back of my shed where I have prepared a level site for a 24 metre shadehouse , bunch of media beds some raft and a row of geotextile bags fed with fish water (no return from bags)

No easy way to say this

Main problem you have is your system is overloaded you will have to do a major expansion or thin your fish out , generally accepted to have 20 litres of WET media for every eating size fish you have , so long term about 7 or 8 fish .

If they big eating fish like trout you will need 25 litres of media for every fish .

http://www.backyardaquaponics.com/guide ... -stocking/

You have quite a lot of fish in 200L of water so keeping your water clean enough will be a constant challenge (Media Beds will quickly clog up)

I think the Chop 1 is a better option as the running costs are lots less (Pump Size) the pump in a chop 1 only has to be big enough to turn over the fish tank volume every hour (generally accepted practise)

However that's the situation in Australia we get hit with high power costs

The Chop 2 is a handy variation when we need to pump to different heights / areas , eg if you don't have room to run your system in a line like I can or the land has a lot of slope , components can be spread out water pumped to all components at different heights and run back to a sump however the pump has to be big enough to supply the fish tank and all the other components at the same time so more expensive to run.

What I was getting at is if you can run SOME of your water through a constant flood media bed then THAT water goes into your raft THEN returns to your sump this will clean your water up (water that comes out of a CF Bed is pretty clean)

Your diagram shows 20mm pipe from your RFF I doubt you will get enough gravity flow through this pipe to keep your fish tank clean (200Lph) Chop 1 type

You could run Chop 2 (pump to fish tank and RFF keep the rest the same and see how it goes) Fish tank returns to sump

Or set up as your diagram only split the water flow from fish tank , some water to RFF and the rest of the water returns to sump.

Lots of variables in AP plenty to keep you scratching your head

Anything will work to varying degrees.

Hope some of that makes sense

I'm really sorry to hear about your accident Terra. I have been really busy with work and haven't had the energy to put in much work in my aquaponics system. Thanks for sharing your knowledge with me. I will have to make a decision on what to implement next. I wish you good health

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Hi Terra, how often do you have to clean your growbeds if you run a Chop1 system please?

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