What's wrong with this ? or The New system

[Hotrodmike]

Ok I am really hoping the answer to this is "Nothing"
I have been searching and researching this for about a year but only got into doing something a few moths ago after I lost my company . I have given the spec's of what I was doing but will rehash ,just so no one has to go looking . I know this is not rocket science but in the back of my head I keep thinking I'm going to F'up something . Tuning I understand ,failure would be a big problem .
Fish tank is 1550 gallon poly water tank that I will cut part of the top off for access . At this point I have dug a hole ,that about took the wind out of me ( not hole digging country ) to set the tank so that 32" of the 48" water level will be below ground level ( 16" of water above grade ) .
The pump is a Mag drive 1800 GPH pump that will be external off a tank bung about 3" off the bottom of the tank .
Air will be from a 200lpm (8cfm) pump to 2 air-membranes and maybe some air in the GB's
I was going to run a 4000GPH pond filter as I do plan to run some DWC and NFT on the system on top of the Fill and drain beds but I am not sure if I am just being redundant and may leave it out of the equation for now .
For starters I plan to build 4 -3'x6'x16" flood and drain beds with Affnan's bell siphons as this is all that will fit in the greenhouse till I can afford to expand it . I will just have to adjust the fish load for the beds and not the tank .
Now some things or should I say details I am not to sure of . First off on the bell siphon . How much drop out of the bed do I need to get a good flow and should the return line be below my bed drops or just below the beds ? As the bell siphons will be using 1" exits what sizing should I use on the main drain line back to the tank , I was thinking 2" should be ok . The one thing I am trying to do is keep the beds from being too high and yes I understand the first rule of plumbing " S##T Runs Downhill " So I do understand all drains have to have a fall rate to work . The only thing I keep thinking is to keep the beds lower I have to either dig the tank deeper (I would hate that ) use a sump ( but that would entail another pump and digging another hole ) or just raising the beds up . Since my water level will be at 16" and the beds will be 16" that is already 32" with no drops in the runs or drops on the siphon . I also would hate to have to get on my knee's to do anything with the fish
So any simple input or am I just getting too anal I just can't afford any costly mistakes at this point .
Have A Kind Day
Mike

[davidstcldfl]

Hi Mike, I like my fish tank to stay at a constant heigth...that's just me.
Your fish tank is also going to act as your sump, so your water will go up and down a little.
Of course your tank is pretty big....you may not even notice.
Your F&D's are about 180 gals....they may only hold 40% of that, after the media is in....aprox 72 gals per bed. Even if all 4 fill at the 'same time', your only looking at 290 gals out of 1200 to 1300 plus gallons of water.

I'm just starting to use 'Bells'....so I really can't say much there. Except, I've heard only good things about Affnan's.

A 2" drain 'might be' ok....what's the odds of 'more then' 2 bells kicking in at the same time ?
You will get a 'bio' build up inside the pipe, which will slow it a little.
If you wanted to lean towards 'over size'....or if you think you may add on in the future (?).....
You could jump to 3 "....'or' .... run 2 differant drain lines. Tie two of your F&D's to their own 2'' drain, and a differant drain, for the other two beds. Might be easier then the 3 " drain.

It's cheaper to go bigger 'now'...less work and 'no kickin' yourself later'....
Bigger is better, when it comes to pick-up trucks, guns and drains..... :P and pizza's and paychecks too.

[stucco]

If your bed is 3x6 I would go with at least 1 ½ pipe for the discharge pipe. I’ve got 2” on my 3’x7’ bed and it works great. The thing that has worked for me is the end of the discharge pipe is running uphill slightly. I mean that I no matter how far the discharge pipe is running downhill the end should be pointing up ½ to ¾ the thickness of the pipe to create a slight trap. I hope that made sence!

[badflash]

If you only have 1 bell siphon that is a 1" standpipe, a 2" drain is fine. Be sure to put a cleanout on it. Stuff grows in the pipes and you need to be able to clean them. Like stucco said, you need a little back pressure on the siphon to get it to kick. I put a little trap on mine before it goes into the main drain. Mine drops 6" from the bed, loops up 2", then slopes another 3 back to the pool.

[Hotrodmike]

Thanks guys
Dave I understand the tank will be the sump and each grow bed will take it down about 1" so even all 4 at once would be 4" so that doesnt bother me too much . As for the 2" if thats the biggest problem I encounter it's all good I also have a bunch of 2" laying around from my spa days that's what made that choice .

Stucco Are you saying 1.5 for the bottom of the bell or on the main drain line ? The trap part I understand and am guessing thats to prevent to much air in the line breaking the flow.

Bad Yes one siphon per bed and I thought from what I have read that 1" should be ok for that sized bed , yes ! I know basicly it is sewage and I had planned a clean out on both ends . I was wondering whether it needed a straight drop or you could do a P-trap type coming off .

See that's what I mean if the water level is 16 " above grade the bed is 16" deep ,I drop 6" with plumbing ,then give it another couple inches for drop in the run . All that adds up to 41 " which is a bit high for the top of the beds . Then I have to put two beds beside each other ( so really is a 6'x6' split bed ) It becomes very hard to reach the inside plants at that height . I was hoping to figure a way to get the beds down with out redesigning the whole system . I was hoping for a simple fix ok at least one that did not entail this old man digging anymore rock ,Rock sucks !
It is looking more and more like digging may be the only solution
Have A Kind Day
Mike

[stucco]

Stucco, Are you saying 1.5 for the bottom of the bell or on the main drain line ? The trap part I understand and am guessing thats to prevent to much air in the line breaking the flow.

1.5 For both the stand pipe and the discharge pipe. The stand pipe is the pipe that sticks up from the bottom of the bed that the bell slides over. With that size stand pipe the bell should be 3"
I have a bed that is 2'x6'x12" that I used a 1" stand pipe for and I’m not happy with how fast it drains compared to the others. I like a slow fill fast drain and I’m sure that some will disagree, but this is what has worked for me. Now you have a kind day!

[stucco]

I just realized that you are using an affnan type siphon and now as usual I have no idea as to what I’m talking about.

[davidstcldfl]

I just realized that you are using an affnan type siphon

I think Stucco is right.....I don't think the 1" stand pipe, will drain the bed 'fast enough'.
Each bed will have at least, 70 gals of water to be drained. MHO....I'd go 1 1/4 or 1 1/2 inch stand pipes and discharge. ( At least, build your stand pipe and discharge, out of the thin wall 1"...that way the ID is bigger, then the schedule 40)

You'll still use Affnan's design....just have to 'size up' all the parts, accordingly.

[Hotrodmike]

I know I must be S.O.L if I'm confusing the moderators !
I also see everyone is avoiding my height question as I already figure I am going to be back in the hole picking rock .

Now as for the siphon (glad I did not order all my bulkhead fittings ) if I go say 1.5 " how big does the bell need to go 2" ? or bigger ? Stucco are you saying 1.5 x 3" bell fitting as that would end up at least 4" for the dome and 6" for the screen pipe ? or where you not thinking Affnan style ?
Your confusion is contagious

Man that puppy will sound like a row of heads going off . To think I thought getting Blues was going to be my biggest problem ! This will also mean I will have to up the main drain line to 4" if I have 4- 1.5 drains . Should I toss this up on P.A ? As they seem to be more into the Affnan's bell . Is there a formula on the bell size as to increased volume vs drain size

I was really hoping to not have to fluff up my hair and put a lab coat on

Stucco , No I don't get one till everyone else gets theirs ,kinda like the last one out of the room turn off the light thing Sooooooooo ( It's not about what you get it's about what you give ,it all goes round )
Have A Kind Day
Mike

[jackalope]

See that's what I mean if the water level is 16 " above grade the bed is 16" deep ,I drop 6" with plumbing ,then give it another couple inches for drop in the run . All that adds up to 41 " which is a bit high for the top of the beds . Then I have to put two beds beside each other ( so really is a 6'x6' split bed ) It becomes very hard to reach the inside plants at that height . I was hoping to figure a way to get the beds down with out redesigning the whole system . I was hoping for a simple fix ok at least one that did not entail this old man digging anymore rock ,Rock sucks !
It is looking more and more like digging may be the only solution
Have A Kind Day
Mike

Let me see if I can help out (or maybe confuse the issue some more) 16" for the FT + 6" for the drain drop is 24" to the bottom of the GB .... so if your GBs are 16", that makes 40" +- and inch or so here and there ..... a six inch drop is a pretty good drop (where I come from) if the GBs aren't located too far from the FT. And, if you shorten your pipe going into the FT so that it acts somewhat like a fountain of sorts, it will act as an aireator for the FT which will lessen the energy requirements - especially if each GB has it's own drain to the FT. That kind of aeration is much more efficient and better than pumped air form what I've read - it adds much more oxygen to the water than air stones ..... you could just put a p-trap on the end and there's your fountain I just measured my wife's stance (she's about 5'3") and 40-42 inches would not be too high for the GBs, but her reach would only be about 20", so putting the GBs together to make a 6x6 would be out of the question. I would even go as high as 46", because her 20" reach would go past the center of a 3' GB. In the alternative .... rather than digging ...... I would build 2x? walkways a foot or so off the ground so as to raise the GBs before I'd dig that huge hole any deeper (That will also keep her dainty little feets out of any mud/dust that may accumulate on the ground A quick hunt for pallets will give you the needed spacers between the ground and the top of the walkways and a trip to some lumber stores will yield a lot of scrap/reject lumber that will suffice for the walkways. I paid $400 for some rejects about 3 years back that had to be trucked here by semi because there was so much of it (they threw in the trucking free just to get rid of it ), and I'm still using 2x4s all the way up to 2x12s (some are up to 20' long) from that pile. There was also a bunch of scrap/reject tin roofing in that load - enough to build an 8x8' storage shed.

Just my 2 centavos .........