Backyard Aquaponics
A place to discuss aquaponics

Hello all,
My name is John,The Fish Junky,and I am new to the forum and would like some input. I recently got 2 fiberglass "lobster" tubs(approximately 250-300 gallons each) that I am going to "T" together in to a 30 gallon sump and of course put some aquaponic concoction of some kind in to the mix.
I will probably go with a few beds (3-4) that will drain back to the sump by way of a bell syphon in each one;unless it would be better to just let it all flow and drain?
I have a mag 5 to use as the sump pump for filtration purpose,but I am a little confused on how big of a pump needed for the grow beds.
My plan would be to set it up like I have my central system where I keep all of my cichlids in my house.I pump to the top and as one fills it overflows to the next tank(gravity).In this case~ the next grow bed to the next grow bed to the next and back again to the sump.My question is,what size pump(s) should I get for this purpose?And any other advice or ideas would be welcomed as well since I'm new to AP also.
Oh I also would like to know if hydroton or perlite is a "must" I see people use river rock so I was thinking, I have over 300 lbs of fish tank gravel outside in garbage bags that would be good to use or use that with hydroton on top possibly?
Thank you,
John

Hi John

The rule of thumb when sizing your pump is to be able to turn your water volume over about once an hour... which GB set-up you use may make a difference to the pump needed tho... ie: constant fill vs flood & drain on a timer (15mins on 45 off is common, but I think you would need a pump 4 x the size as its filling in 1/4 of the time...?)

Our system can hold 18,000L water, so we just got a couple of pond pumps that were that vol (18,000lph ea, one for FT, one for ST, + one spare )...but our pump is only switching off for less than 5 mins every hour as we run shifts one after the other, so it is equivalent to constant pretty much.

how small is your aquarium gravel? It may be too fine... once your solids and plant roots start building up in the system you may have drainage problems - 20mm is what most try to use.

Would depend on how you set-up your GBs as to whether you could top with hydroton and be OK... ie: how much your putting in the bottoms of them... will let someone more experienced guide you on that one ... BTW, not sure why but I dont think perlite is good for use in AP.

Hope that helps

thank you for the reply and help.so the mag 5 should handle the turnover for me as far as "filtration" for the fish,as far as turning it over once an hour; but I'm still stuck with what size pump I should be using for the flooding of the beds?
From what I gather,most use smaller sized pumps just to keep the GB "wet" for the 15 minutes "on" and then it will drain "off" for the 45 minute interval. I could be wrong there? but I don't think the plants would do well "submerged" so to speak, for those 15 minutes~ right or wrong?Or is that what I want?
Or,am I aiming to just "water the plants" and allow them to slowly dry almost for the 45 minutes and get oxygen to the roots and then it fills back up and starts all over?

As for the gravel size,I'd say its the size of a smilie < like that. or a pencil eraser.But I can see it clogging up eventually as you mentioned also. Should I use larger rocks then and then top with hydroton? I've seen others and read of others using river pebbles and that is why I compared them to the gravel seeing it's roughly the same size.But~ it's okay, I'll scratch the gravel idea.I was just trying to conserve some money on buying all that hydroton and use some stuff I had.
So,I think I'm gonna go with 3~ 50 gal.(190 L. ?) rubbermaid containers as the grow beds.(forgive me on the gallon thing~ I'm American and it's what I know I gotta look up liter to gallon,mm to inch~ quite a bit on here so 20 mm is roughly 3/4" to me and I guess if that's rule of thumb~ then my gravel I had in mind is "out the window".
So if my 3~ 50 gal containers = 150 gallons(570 L?) then I need a pump that will turn over 150 gal or 570L in 15 minutes? SHEESH!!! I'm not sure that's right? Maybe the constant fill and drain without the bell syphons would be better for me then?very confused on the actual pump part of all of this.
Thanks

correct. you want to turn over at least the volume of your FT every hour, whether you do this on flood and drain of constant flood beds is up to you. CF beds will need highly oxygenated water to get the oxygen to the plant roots. FD beds oxygenate by draingin and filling. times vary, mine is a 15/15 FD system.



this gravel will clog very quickly. use 12mm= size rock


not necessary, but makes planting a little easier


pump size determined by FT volume, not GB volume, but for a 150gallon you would need a pump that turns over 150gallons in the 15min it is on. hence why i cut my drain time down. by having the pump on for 30min/hour i half the size of pump i need
Thanks[/quote]

also i think you should distribute water to GBs evely. distributing in a 'chain' will mean that the fisrt one may fill up with solids and cease to function.... major dramas. also the last one will miss out on nutes for the plants.

good luck

An assumption that's often made.... but not true in either case....

Both the solids and nutrients are in solution... and end up over time essentually evenly distributed amongst the growbeds...

Our F&D time is down to 12/50 now which we are pretty happy with... was 30/120 when we started... so no hard and fast rule of 15/45 - use whatever works!

Dont have to worry about plants rotting or whatever from being submerged with flood and drain, the draining sucks oxygen down past the roots which is why worms do so well in AP and not in a puddle of water (no DO so they drown).

We ended up using flood and drain as there are a few people who have had probs with the syphons either not shutting off, or not starting due to flow rates... figured it was easier to control fill times and drainage hole size

Hydroton is easy to use as it doesnt hurt your hands ( river stone is probably next down the line for ease of use when looking at gravel based GBs)... and hydroton is also good for root veggies like carrots which is why we are going to put 1 or 2 beds in... but many people use volcanic rock (scoria) as its much cheaper than hydroton or river pebble, search for the 'which is the best media' thread (think thats what its called?... maybe just search for 'media types' ) ... there are a few different threads discussing media pro's and con's.... just remember.... limestone bad

Gravel that small will not clog, I've been using 1/4" pea gravel for years. Especially if you put compost worms in there.

Thank you ALL for helping out. The pump thing was what I was having the most trouble with I guess.Reason being~ I was going to use 2 separate pumps for the system.the mag 5 for filtration and a separate small pump for the GB.I guess that's a waste of electric for the most part. I'm used to "over filtration" on my aquariums 3-5 times the turnover an hour on every tank, but realizing this is supposedly not necessary in AP since it's almost opposite from what I see. It's almost suggesting to "under filter" since the plants are all the extra filters I need.Correct?
I have a pond already that is 1500 gallons and is ran with a mag24(2400 gph)but it goes to a 32 gallon plastic drum that starts the filtering~up to a water fall that has three deep areas that also filter before returning to the main pond.Works like a charm and has been running very well.Crystal clear water,healthy fish(koi)etc.Initially I was going to join the 2 new lobster tubs in to the mix and have it all ran together with the existing pond also~ but I am leaning towards 2 separate systems now.
I'd like to keep some of my South American Cichlids in the 2 new tubs and breed them etc. But I definitely know that a Mag 24 would be complete overkill in the AP/GB system,so I'm going to run the GB and new tubs all separately.( for now)I'll start with the Mag5 (500 gph) for starters and go from there.I guess it won't be very long before I know if it's working well or not and if it will need to be tweaked or if another pump is needed etc.

I guess there's conflicting info on the gravel/GB media side of things...If the only reason I have to spend all the money on hydroton is for it not to hurt my hands~well, that is good enough reason to save money to me.But I doubt that's the case.I would think it would keep drainage at its best and allow much more oxygen to the roots as well as making it easier for the veggies to grow.Especially something like carrot. In any case,I'll cross that path as it comes.I know fish tank gravel collects tons of poop and dirt or whatever else since I have to vacuum my gravel at least every 2-3 weeks minimum in my aquariums and see 1st hand what is buried in it.

netab32 wrote:Dont have to worry about plants rotting or whatever from being submerged with flood and drain, the draining sucks oxygen down past the roots which is why worms do so well in AP and not in a puddle of water (no DO so they drown).

We ended up using flood and drain as there are a few people who have had probs with the syphons either not shutting off, or not starting due to flow rates... figured it was easier to control fill times and drainage hole size

^^^Great info.Thank you...but it brings me to the question~ of the draining part now.I thought a bell syphon is in fact flood and drain Or does the GB just have an open drain plug(with stand pipe that fills to the top of the stand pipe and then drains) that would drop or drain to the next grow bed or in to the sump etc.?
On my central system for my fish tanks I have one set up that has a 30 gallon sump tank that pumps up to 5 different tanks.As the top 2 fill,they overflow in to the stand pipe that then overflows and drops the water to the second set of tanks and then down to the next level and back to the sump where the process is repeated.It's a basic gravity fed system.
This is what I was thinking would be a traditional fill and drain.I'd put bulkheads in each grow bed with a stand pipe to the height of water that I would want to fill up to and then once it reaches that height in the GB it would overflow to the next bed etc. In this case, I would always have some water left at the bottom of the GB at all times but wouldn't effect the system negatively i'd think. OR the bell syphon is basically the same thing however it allows the water to go higher in the bed and allow the roots more water time before the syphon kicks in and drains the beds almost completely.Someone please let me know if I got all that right?

Dave has a good point... I suppose we decided on the 20mm river stone as its circular like the hydroton so has more gaps for oxygen, plant roots, etc. and not sharp like the blue metal or volcanic rock... and a few had suggested that pea gravel clogs as it has less gaps when it settles, but it obviously works too ... maybe as you have a few GBs you could do an experiment? Use the aquarium gravel in one, hydroton in another, etc, etc... and see what works best for you, and which plants do best in which GB?

Your right, siphons are a type of flood and drain, but ours is a timer flood and drain system... hence the 15/45 or 15/15 etc ratios freoboy and I were talking about... using the timer to switch on for however many minutes you need to fill your GBs, then off to let them drain down.

Putting a small hole into the bottom of the standpipe will let the water drain once the pump turns off. If you used this system you would have to keep the pump on until all the standpipes are overflowing and filling the next - so that they would fill faster than they are draining

The reason I thought syphons might not work is because if your flowing from one bed into another it would be hard to regulate flow to set each siphon off?

Or perhaps you could use a trickle system with the loop of pipe with lots of holes so the GBs arent actually filling... just draining straight away into the next one which has the same ring of pipe with holes? Dont know the finer points of this type of system tho....

BTW I think the water turning over once an hour thing is so that its filtering and oxygenating the water enough for the fish, but is allowing enough time for the bacteria and plant roots to take a good amount of the nutrient etc out of the water before it goes back into the FT - too fast and it doesnt have a chance to... just what I read.

just a few suggestions and hope Im helping and not just confusing the issue for you?

Or giving any bad info

No actually it all makes perfect sense to me.Not that I'd know if it's right or wrong
what my plan was, is as you mentioned ~ one bed fills and then drains to the next bed on to the next etc.So,initially it would really only need to fill the 1st bed for the most part. And of course just as any other system~ I will baby sit it and see what happens.How long it takes to fill the 1st bed and drain to the next and so forth so I know how many minutes to keep the pump running etc.I seen a few videos that were calling it ebb and flow I think
I'd think in theory~ I only fill the first bed until it kicks on the bell syphon and drains to the next bed and so forth~ but if that doesn't work I'll toss the syphons and just let it flow free. Each bed will be staggered in height so that it all continually drains on to the next until it hits the fish tank and sump area where it will repeat.
On another note~ went to a local supply place today and the 50 gal. rubbermaid containers were $99+ each. I'm not spending that. So I did find sheep feeders that are
10 ft X 2ft X 16in (almost 200 gallons each)and only $127 ea.
I may have to grab 2 of them instead.
Or~ I may just build 2 long beds out of wood and line them with pond liners and call it a day.I have to do the calculations on what is most cost effective.
I really like the experiment with gravel beds having different types and see what does best.It would probably help other people out as well.Although I bet it's already been done by someone.
Hopefully this starts sooner than later and I'll keep updating my progress with pictures and a log of some sort.I picked up 2 jiffy seed starters already and will be starting my seeds tonight.Project with the kids

Just to clarify tho... siphons and timers are 2 different F&D systems... dont need a timer for siphons. Hoping someone can offer more info on whats better for a cascade system Spose it just depends on whether you want to use a timer or not

What im wondering with siphons is that whether when the first dumps its water it wont quite fill to the top of the next one and water will sit there till the first siphons again to top it up? Then again it might work perfectly Might as well give it a go

If your going to test different media it might help if you go from biggest to smallest... hydroton in first as it would take more water as there are bigger gaps, and aquarium gravel in bottom one as it wouldnt take as much water to fill it... maybe this would negate that problem enough... only guessing tho... and perhaps worth another experiment?

If using a timer you would have to rely on the overflows instead of the drainage hole to fill them all before the timer turns off otherwise the next one down from the top (and all the others after) would drain at the same speed and not fill

What you could do is before you fill with gravel drill your hole into the standpipe, and cut a section out along a piece of pipe and slide it over snugly to cover the hole (or slide it inside the standpipe)... that way its blocked, but if you need to use it down the track you dont have to take out the gravel to modify it...you can just reach in and spin (or pull out) the pipe to uncover the hole. Research some of the syphon systems first if you can as they might still use the drain hole so that if the pump turns off the GBs dont just sit full of water.

Also if you can, use a piece of pipe with slits or holes in it over your standpipe thats big enough to get your hand down into (edit: or tongs if you dont want to use up that much room) to remove gravel etc - might take up a bit more room than you can spare tho but its good to have as you can turn it to clear roots if they grow through (or adjusting the pipe as above).

Reckon you still might be better off with a constant trickle system when your cascading... running pipe back and forth over GB and letting water trickle down through gravel. Dont have to worry about timers or getting all the siphons right... might be worth ruling this one out first before you look at the others... just a thought

Cheers

use a trickle (constant flood system) with stand pipes to raise the water level to 30mm ish below the surface of the gravel i rekon thts your best bet

That's a good thing.I'm not very good with timers.Here's a video link of what I am looking to do but its on a baby scale compared to what I have in mind for my AP set up.[url]
http://www.youtube.com/user/creuzerm#p/u/55/G0U1_hN0PjE[/url]

I did think of that also.My only solution is continue to flood the main GB in the first of the "cascade" more than the others and have different heights of stand pipes in each bed to compensate for this.

I think this will also help with different levels of water loss as it goes from bed to bed.

Well,actually they'd have to all get filled in order, I believe, for it to work regardless.

great idea and I was thinking this as well.
If you watch the video on that link~ I am going to do the same as far as threaded couplings so I can add or subtract height and do anything else I need to do~ if its all mostly threaded pipes.
That's basically my plan but as I said, I will use bell syphons.If by any chance it doesn't work I'll just do the stand pipes alone and take out the bell syphons but to e honest i think it will work.
Thanks again to both of you for the help.