Backyard Aquaponics
A place to discuss aquaponics

Hi Guys,
I have the ability to flood my GB and have it flow into and flood GB2 followed by GB3 and so on until GB7
Can anybody see a reason as to why this would be better, or worse than individually filling each GB?
Cascading them would use less pipe, valves, effort etc, so I like the idea, but as for filtering, the GB at the bottom would not get any solids.
Also the plants at the bottom would get less nutes?
Would Bacteria grow in the bottom GBs?

I just would like to hear some ppl chat about the pros and cons.

bacteria will grow in the bottom grow bed
last bed will not get less nutrients (think of the system as a multi pass ammonia conversion and nitrate uptake system, not a single pass.)
first bed may clog as it will bear the bulk of the solids

Maybe consider pumping up to a header tank (distributor tank) that feeds all growbeds, run an overflow pipe from the header tank back to the pond / aquarium for aeration purposes.

Best wishes

Johnnie

Throw composting worms in the top bed.

I think the header tank Idea would be better than going 7 levels in line. Is it possible to pair up the tanks so you have 3 sets of two instead of having to plumb them individually? Also in a cascading system you need to size the tanks smaller as you go in order to ensure you siphon kicks in with each cycle. Other wise you may have water standing in a bed for a long time depending on your flood cycles. Just a thought.

The worms a re a good idea Janet.

Thx, my GB has built in float valves, so if I overfill the first I hope to overcome this problem

?? I hve thought long and hard about the relevance, and can only come up with the worms will reduce clogging and break down the solids? Are you for cascading or against?

This is what I thought, but so many ppl (lay ppl not on the forum) have tried to convince me otherwise.

Many ppl were upset I was mixing fresh and dirty water, rather than have fish on 'pure' clean water.

Yeah, I don't have to cascade. Difficulty if I don't is I don't have enough water for fill ALL the beds simultaneously. My current design is for two rows of 7 beds, I can cascade in pairs, or threes etc.

Thanks for your opinion.

Having each one fill individually allows you to take one bed off line for cleaning or for whatever reason.

I'm facing a similar problem. I'm going to overflow my FT into a a holding sump and pump from there to the GB's. That way the FT will be a constant level and the sump will become my buffer.

Cascading is fine in my mind. I think this could have some possible advantages - if they are completely serial, i.e. you arn't filling the top bed whilst the bottom bed is still filling, then you can get away with a smaller sump. (Which was why you're doing this?). You would still need some way to guarantee that you won't start filling the first bed before the last one has emptied or they may eventually catch up to each other.

It won't matter where the solids are - Worms break it down and you get "worm tea" flowing through your system, so it doesn't really matter if they're distrubuted or just in the first bed.

The Ceres AP system runs cascades down a hill somewhere in Melbourne. Maybe go check it out, or their website.

Gemmel that is my main reason yes. To not cascade, and selectively fill GBs will take many 0 pressure valves and extra fittings.

I can't overflow my growbeds, they each fitted with a float valve, as standard when I buy them. I liked this as it allows me to overirrigate, to ensure siphon is made each time. - Also I think I have enough sump water to start two 'waves' of F&D down the cascade if I need to increase flow.

Worm tea... yes, that's good to know. I hadn't considered this.
only cleaning the top GBs even if done more frequently makes me smile more too :-)