Backyard Aquaponics
A place to discuss aquaponics

My opinion too monya - i reckon my beans could not be grown any faster

It just seems to be a lot of extra plumbing work for very little gain compared to a conventional AP system.

Sure it makes hydro better, but not AP.

2c's

1/4" laser cut drip irrigation tubing works as bubbler in my biodiesel washing and drying. It does not plug nor does the solvant action of the biodiesel bother it. It should do fine buried in gravel. In a tank it needs to be wieghted down or it will float to surface. It is available in a cut every 6" or every foot. I use the drip "1/4 in. distribution hose" to distribute air across the 30 ft. green house and run only one large bubbler for two fishtanks, one sump, one to wash biodiesel, and one to dry biodiesel. It is cheaper than vinyl and impervious to sun damage. Tees, ells, and plugs are avilable for this stuff and are air tight.

Air stones often need maintenance so they would be difficult to deal with under gravel. Cheaper air stone need to be replaced regularly as they are not really designed or meant to last forever. The more $$ ones can be maintained but you need to get at them every so often to clean them.

As to why DWC doesn't get as much attention here compared to flood and drain with gravel. If you are going to do DWC, you still need solids removal and biofiltration which now needs separate steps from your grow beds so doing the flood and drain gravel grow beds takes care of three processes in one container. It is just efficiency I guess. Gravel beds provide aerated surface area for the bacteria of your biofilter, it provides mechanical as well as bio solids filtration and provides a place with support for your plants all in one package.

In that Hydroponic picture showing the smaller peppers in the bottles and the larger plants in DWC. Part of the reason for the DWC plants doing better may be they had more room for their roots while the ones in the bottles were root bound. Just because plants are being provided with all their nutrients does no mean the roots don't still need space.

I like DWC for growing lettuce in hydroponics because it is really simple. Take a container, put an air stone in it, fill with nutrient and support lettuce above.

Most DWC AP systems commercially available are DWC and really only meant for growing leafy greens like lettuce. Not having the solids in the grow bed available to the plants apparently makes it more difficult to grow good fruiting plants.

However, if one wishes to make a DWC or NFT section of a system after their gravel grow bed, that may be worth a try.

As to simply adding air stones. Many system have air stones in the fish tanks for supplemental air or emergency backup. I'm working on such a thing currently.

TCLynx,,,you hit the nail on the head. That is exactly my plan ,,a DWC after the gravel bed. Gravel bed sized at twice fish pond because it is this GB that provides bacterial filtration/conversion. Then the DWC .
Gravel beds have the necessary nutrient levels , root support etc for Tomatoes,corn etc etc and then the DWC is used for lettuce,basil etc.

isn't the purpose of the airstones to supply O2 to the root zone not to increase the dissolved DO, since the plants don't use the dissolved DO as well as if they were just exposed to air?

My understanding of using air stones in aquaponics was to keep the DO up for the fish...there is sufficient O2 supplied in the growbeds from the flood and drain

DWC ell!!

I am considering adding a Power Stream Aerator to each grow bed to airate the water as it enters the growbed. Simple way to increase the O2 in the grow bed water without using any extra power or parts.

catching Steve's skimming virus too it seems

It would seem to be a fatal virus, going by his absence...

My thoughts are that the p[ants just need O2 in the water ,, but I do not know for a fact. Either way , this would seem the best place to add oxygen as it is post the algie and therefore oxygen levels at their lowest point in th system and adding oxygen to low oxygenated water is easier ( ahh O2 more easily added to low O2 water).

Awaiting someone who knows , as I'm guessing.

the DWC setup is on the "to do list"..............might convert the "old" system to DWC after i have finnished the BYAP system.

Monya is right though, you'll still need the bio/solids filter........so you'll still need to was the gravel

i'll be using a 200l blue barrel as the solids/bio barrel.

With your 200 litre barrel will you have to clean it [i have an idea i want to try]

have you learnt this from experience?

dads nft is using the 200l barrel and is fine after 1 year.