Backyard Aquaponics
A place to discuss aquaponics

It is threaded on the inlet end and it connects to a Male Hosetail pushed into the 25mm PVC pipe from the pump, but it can be made up with any fittings that suit your pipe from the pump.

The rest of it is just pushed together, no glue in case it needs too be cleaned.

Hi,
On one of the previous pics, showing where your water flows into the GB, what's the basket of green stuff?

Hi Moiz,

They are scouring pads/dishwashing pads, so I can see if there's any excessive build up of fish solids and they are handy when I have to add anything to the system, things like hydrated lime, Epsom Salts, shell grit and Seasol, I can just sit them on top of the scouring pads and they slowly dissolve into the grow bed.

Plus it's just a little of extra filtration.

Thanks - good idea, think i'l try it.

Also, just read back about the venturi.

My current inlet to FT is a spray bar.

If I keep the spray bar, and add a venturi before it, would it still work in the same way and increase DO?

I added the spray bar to help the water circulate and move solids towards my Solids Lift Pipe hence Id like to keep it.

Hi Moiz,

I have the pump running in the sump with a Tee in the pipe/hose about 300mm up from the pump running to a spray bar in the sump for aeration in the sump, then the pipe/hose runs up to the venturi in the fish tank.

You can run both a spray bar & venturi but I think you would need to add the venturi after the spray bar, not before it, and put a ball valve on the spray bar to slow it down a little and allow more flow to the venturi.

I found my venturi didn't perform all that well until I slowed down the volume of water to the spray bay.

I tried making a copy of your venturi.. my pump is 3000L/H running through 25mm pvc pipe and my T piece is 15mm with 6mm clear pipe acting as air inlet, but yikes its slowed the water flow down some horrific.

Have I made a miscalculation? or done something wrong? yup but what?

Tonzz you might have gone a bit small, and did you bevel/taper the end of your clear pipe?

Here's a rough idea of the sizes I used, I just picked up fittings off the shelf in Bunning's, and built there in the store, starting with a 25mm threaded fitting to match the end of the hosetail connector, that was the only size I needed to know, the rest was all ad hoc.

I just went with what fitted and I didn't need to check on any sizes, just what looked like it would work making sure I had a reduction with the Tee compared to either end.

I'm not sure if the Tee is 20mm or 25mm, it looks like it might be 20mm and not 25mm, but the threaded piece is 15mm.

If you look at Robob's video, CCBear's venturi doesn't restrict the flow and neither does mine, so I think you might have gone too small or not bevelled the end of your tube.

The only restriction is where the Tee and it's connection fittings are slightly smaller in diam. than the other 25mm end fittings.

Tonzz post a photo and see if we can work it out.

bit late I pulled it off and fitted a straight piece of pipe.

I have 25mm pipe, Tee piece was reduced to 15mm with 6mm bevelled pipe in right direction (I read that part) me thinks I went to small,
where you have a 25mm45* bend I have a 90* going into FT then another 90* to get water swirling around the edge of tank.

ah well another trip to the big shed, when in there this morning I directed a customer to the right place because attendant didnt know the item was....

A 90 degree elbow would restrict the flow more than a 45 degree elbow would, then a second 90 degree would slow things down a bit more.

ah well another trip to the big shed, when in there this morning I directed a customer to the right place because attendant didnt know the item was....

I was there last week looking for a poly pipe punch to set up another misting system, I had 4 staff searching for the the punch, 3 didn't know what a poly pipe punch was, and the forth guy knew what is was but couldn't find it, my son found it after they had all given up.

They are not my favourite store but you know they do sell what your looking for, if they have it in stock. In their defence some products are stocked by sales reps from outside the company and not Bunning's staff.

I'm thinking of up sizing some of my plumbing in the system.

Now that is a Tee.

Can you explain the ins and outs on this model?
Outs on the top with the cowls?
Ins on the bottom with the drilled holes?
Solids tap elbow to flange sitting on bottom?


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The extra volume of water in the larger barrels really forces the solids out far better than the smaller barrels.

Can you explain the ins and outs on this model?
Outs on the top with the cowls?
Ins on the bottom with the drilled holes?
Solids tap elbow to flange sitting on bottom?


If you had a tap on a 9litre bucket and a tap on a 220litre barrel, the weight of the water above the tap in the 220litre barrel would be far greater than in the bucket and have a much faster flow than the bucket would.

I can't see any outs on the top with the cowl, being longer and larger than a normal PVC Cowel gives you a better flow with less chance of bio media reducing the flow. Plus nothing in either barrel is glued and can be removed to clean.

Same on the bottom the drilled holes in MBBF inlet again gives you a better chance of not having bio media restricting the flow than just a normal PVC Cowel would. I started out using normal PVC Cowels and found the bio media did restrict the flow.

The solids flange is a 90mm to 50mm PVC Reducer with 3 x 4mm - 5mm slots cut in the bottom, they are small enough to not allow any bio media to be drawn out of the MBBF tank. The hole in the side of the barrel is drilled 10mm lower than the height of unit to keep permanent downward pressure on the reducer to stop any bio media leaving the barrel. With nearly 200litres of water above the reducer you get a very good flow to drag the solids out.

Jay I also use a 100mm paint brush pushed into a length of PVC pressure pipe to sweep any solids that don't get drawn out of the barrel, but that is very rare, and you can see the bottom of the barrel almost every day.

Thanks mate that's perfect
I'm going to use 100ltr green wheelie bins
The fall from rff to MBBF - does it have to be a certain amount for flow?

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I would just keep the outlet from the RFF as high as you can, and that will depend on the fall from your fish tank and the height of your grow beds. The outlets on both filters will need too be higher than your grow beds.

Then make the MBBF inlet as low as you can to get the maximum fall, and the outlet will have too be the same height as the RFF outlet or slightly lower. I don't think it makes a lot of difference, but the more fall you can get the better.

The 100 litre wheelie bins will make great filters, I'm about to build a Mineralization tank and a de-gassing tank using 100 litre wheelie bins.

Joeblow this is brilliant, thank you so much for creating and updating the drawings with the clear water draw off spigot.
Fascinating stuff here making me ask questions:

What part are you two calling "cowls"?

Have you measured the flow through you filtration?

Will your new minieralization tank be a similar layout as the MBBF?

"Wheelie bin," If I understand this to be a trash bin? Why wheels?
Thanks
Brian