Dear Drumurphy,

How many worms is enough? Is there a per volume worn count guideline? :)

I remember reading difficulties about isolating duckweed from the rest of the rafts. How do I solve that? (put duckweed in the last raft before the NFT?)

Oh , and I forgot. I'm planning on putting Pumice into the media beds. We have plenty of that here.

I'll connect the rafts together with 3" pipes. I'm guessing they'll be OK because they're all interconnected at the same height, and will act as one big bed.

What's a bypass riser? Do you know where I can find more information on how to make one? It definately looks like something I need.

drumurphy said:

You might consider where in the loop your water will be the cleanest, and try to introduce that water to the NFT section - over time the raft tanks will collect particulate debris, roots, hunks of coco fiber etc. and that is going to foul the NFT, which is the portion of your design most sensitive to mucking up. Also, it's nice to introduce duckweed into your rafts - fish food and algae cover for open spaces, and you don't want that flowing into the NFT.  Hopefully as your water comes out of your media beds, it will be nearly free and clear of particulates. 

Also I'd consider trying to send your fish tank water directly into your media beds - put worms in at least the first 2 or 3 beds, and let them go at the waste rather than filtering with a clarifier - with a clarifier you will be throwing away lots of good mineral value every time you clean it - possibly devote one bed (first) just to worms - that way you can turn it occasionally if needed - At least for us, loss of micro-nutrients are our biggest problem - We only have raft tanks now, and want to exchange the clarifier/filter system for media beds in the near future - 

With those mods, If you still have particulates at the exit point of your media beds, that is where I would consider a filter point - build a simple mineralizer tank (good sized) loaded full of shade cloth - it will filter any really little stuff that gets past the media, and then bacteria can munch away at it - it should rarely if ever need cleaning, and if it does (if it starts to have unpleasant odor) you just drain and back hose the cloth from the top down - .

Spend a lot of time thinking about your water flows - each entry point needs to be below the previous exit point, so you typically need to elevate your pump destination pretty high. The fish tank could act as a sump (lowest point), pump up to media beds, flow to the mineralizer, flow through the NFT, into the rafts, into the fish. A nice big loop. Only one pump, no timers, switches, valves etc .Using exit risers, you can't overflow - put a bypass riser in your media bed in the event your bell siphon/s fail (clog) for some reason. Use oversized pipe. 

Looks like a fairly large system - what's your goal??

AM

Oh , and My purpose;

It's not huge, the beds are 150cm x 75cm each. and the greenhouse is 75 square meters total.

This is a trial system . If I succeed , it will be a commercial venture , roughly 10.000 square meters.

I'm guessing sales won't be an issue with 12 million people in the city :)  

Cengiz BAYAZIT said:

Dear Drumurphy,

How many worms is enough? Is there a per volume worn count guideline?

I remember reading difficulties about isolating duckweed from the rest of the rafts. How do I solve that? (put duckweed in the last raft before the NFT?)

Oh , and I forgot. I'm planning on putting Pumice into the media beds. We have plenty of that here.

I'll connect the rafts together with 3" pipes. I'm guessing they'll be OK because they're all interconnected at the same height, and will act as one big bed.

What's a bypass riser? Do you know where I can find more information on how to make one? It definately looks like something I need.

drumurphy said:

You might consider where in the loop your water will be the cleanest, and try to introduce that water to the NFT section - over time the raft tanks will collect particulate debris, roots, hunks of coco fiber etc. and that is going to foul the NFT, which is the portion of your design most sensitive to mucking up. Also, it's nice to introduce duckweed into your rafts - fish food and algae cover for open spaces, and you don't want that flowing into the NFT.  Hopefully as your water comes out of your media beds, it will be nearly free and clear of particulates. 

Also I'd consider trying to send your fish tank water directly into your media beds - put worms in at least the first 2 or 3 beds, and let them go at the waste rather than filtering with a clarifier - with a clarifier you will be throwing away lots of good mineral value every time you clean it - possibly devote one bed (first) just to worms - that way you can turn it occasionally if needed - At least for us, loss of micro-nutrients are our biggest problem - We only have raft tanks now, and want to exchange the clarifier/filter system for media beds in the near future - 

With those mods, If you still have particulates at the exit point of your media beds, that is where I would consider a filter point - build a simple mineralizer tank (good sized) loaded full of shade cloth - it will filter any really little stuff that gets past the media, and then bacteria can munch away at it - it should rarely if ever need cleaning, and if it does (if it starts to have unpleasant odor) you just drain and back hose the cloth from the top down - .

Spend a lot of time thinking about your water flows - each entry point needs to be below the previous exit point, so you typically need to elevate your pump destination pretty high. The fish tank could act as a sump (lowest point), pump up to media beds, flow to the mineralizer, flow through the NFT, into the rafts, into the fish. A nice big loop. Only one pump, no timers, switches, valves etc .Using exit risers, you can't overflow - put a bypass riser in your media bed in the event your bell siphon/s fail (clog) for some reason. Use oversized pipe. 

Looks like a fairly large system - what's your goal??

AM

The point would be to put the NFT before the raft beds - the duckweed would be downstream from the NFT, and would need to somehow migrate through the media bed/mineralizer sub system to get to the NFT - love duckweed - free fish food  - 

Flows would be as follows -

1) Fish tank (lowest point) pump to media beds (highest point)

2) Media beds gravity flow down to mineralizer tank

3a) Mineralizer tank gravity flows to NFT  

!!!!  at this point I realize you are probably going to need more flow through the entire system than the NFT subsystem will need - so you would probably be diverting a portion of the flow from the mineralizer to the NFT, and the remainder to the raft beds; the NFT will flow to the raft beds as well.!!!

3b) Mineralizer tank gravity flows to Raft beds

4) NFT gravity flow to Raft Beds

5) Raft Beds gravity flow back to the fish tank

This exercise makes my other point - spend a lot of time visualizing the flows of water before you lock down your design - think about flows backing up, paces where flows will pool and possibly stagnate, how you will limit the build-up of debris, how will you maintain standard water levels in the various sub-systems, what oxygen levels might look like at various points in the system (important to maintain an aerobic environment almost everywhere, especially the media beds) - it's half the fun IMHO - your system will look it's best (well, cleanest) the day you fill it with nice clear water, and it will quickly fill up with life and gunk in ways and places you may not exactly appreciate ;) Once you know where and how much water you need throughout the system, then try to design your pipe as elegantly and simply as possible - i find that simplicity always works best - also, the less pipe and the fewer bends etc, the higher the flow rates, and the slower the gunk up rate ..... the more you can turn over your water the better everything is ...... anyway, think it all through, and then think it through again - tearing out pipe or rebuilding platforms because you need 5 more inches of elevation somewhere is a real buzz-kill .... been there ;). 

I assume you are using bell siphons to drain the media beds - The overflow riser I mentioned would be a simple secondary riser with an input slightly higher than the bell siphon initiation level, but lower than the top of the bed - if the siphon failed to open, water would flow down the overflow riser into the mineralizer rather than overflowing the bed and out on to the ground, which would eventually drain the entire system .... unhappy fish, recycle the entire monster etc .... a bad aquaponics day ..... this idea of an overflow may be (is probably) unnecessary as the big problem with bell siphons is the things not closing, rather than not starting, but I don't like any point that could possibly become a plugged up tank with no way to drain the water to where it belongs - it requires a 2nd bulkhead for each siphon point, and piping to the mineralizer - think of it as a taller bell siphon without the cap and exterior sleeve - again maybe not necessary as long as you do cleaning and maintenance on the siphons - I put the backups in our previous system - 

AM

Cengiz BAYAZIT said:

Dear Drumurphy,

How many worms is enough? Is there a per volume worn count guideline?

I remember reading difficulties about isolating duckweed from the rest of the rafts. How do I solve that? (put duckweed in the last raft before the NFT?)

Oh , and I forgot. I'm planning on putting Pumice into the media beds. We have plenty of that here.

I'll connect the rafts together with 3" pipes. I'm guessing they'll be OK because they're all interconnected at the same height, and will act as one big bed.

What's a bypass riser? Do you know where I can find more information on how to make one? It definately looks like something I need.

drumurphy said:

You might consider where in the loop your water will be the cleanest, and try to introduce that water to the NFT section - over time the raft tanks will collect particulate debris, roots, hunks of coco fiber etc. and that is going to foul the NFT, which is the portion of your design most sensitive to mucking up. Also, it's nice to introduce duckweed into your rafts - fish food and algae cover for open spaces, and you don't want that flowing into the NFT.  Hopefully as your water comes out of your media beds, it will be nearly free and clear of particulates. 

Also I'd consider trying to send your fish tank water directly into your media beds - put worms in at least the first 2 or 3 beds, and let them go at the waste rather than filtering with a clarifier - with a clarifier you will be throwing away lots of good mineral value every time you clean it - possibly devote one bed (first) just to worms - that way you can turn it occasionally if needed - At least for us, loss of micro-nutrients are our biggest problem - We only have raft tanks now, and want to exchange the clarifier/filter system for media beds in the near future - 

With those mods, If you still have particulates at the exit point of your media beds, that is where I would consider a filter point - build a simple mineralizer tank (good sized) loaded full of shade cloth - it will filter any really little stuff that gets past the media, and then bacteria can munch away at it - it should rarely if ever need cleaning, and if it does (if it starts to have unpleasant odor) you just drain and back hose the cloth from the top down - .

Spend a lot of time thinking about your water flows - each entry point needs to be below the previous exit point, so you typically need to elevate your pump destination pretty high. The fish tank could act as a sump (lowest point), pump up to media beds, flow to the mineralizer, flow through the NFT, into the rafts, into the fish. A nice big loop. Only one pump, no timers, switches, valves etc .Using exit risers, you can't overflow - put a bypass riser in your media bed in the event your bell siphon/s fail (clog) for some reason. Use oversized pipe. 

Looks like a fairly large system - what's your goal??

AM