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View Full Version : All around questions (cycle times, sizing)



dwaller
01-28-2010, 09:36 AM
Hello, first time poster, short time lurker :)

I'm up in MN looking to setup a system similar to wolfracers. I'll likely be going with a 150 gallon tank to raise tilapia and/or yellow perch. I'll probably end up going with about 5, 20 gallon grow beds, and i'm liking what i'm seeing with the loop syphons that wolfracer setup. Here are where my questions come in to play.

1) I'd like to have the beds gravity fed, and only need to use a pump to take water from the sump back to the fish tank. Is this feasible?
2) With a 150 gallon tank (probably filled with ~135 gallons), is it best to go with a round tank, or one of the rubbermaid stock tanks from somewhere like tractor supply?
3) What should i be doing for a flood/drain schedule in a system this size? Do I need to have less grow beds, or a bigger tank to feed the number of grow beds I have?
4) I'd like to go low-power on the pump, and am thinking of going with a DC EL-SID10B12 pump, which runs off of DC. The downside to this, is that with a 30" lift, I'd be limited to about 2.5GPM flow.

After typing all of this out, I realized I'm really wishy-washy on all of this at the moment. I'd be open to any suggestions on what type of system to put in a 10x12 greenhouse.

I'm excited to get my system put together, thanks for any help I can get.

urbanrunoff
01-28-2010, 01:35 PM
The lady who runs the tilapia workshop in san diego, suggests FT's to be at least 35 inches in height. She says it makes a difference but lots of people have shallower tanks.

I have a Rubbermaid Water Trough and they are excellent quality. My local Ace store was able to custom order it for me so i did not have to pay for shipping.

Here is a diagram of a one pump flood and drain with sump system
http://www.aquaponics.net.au/forum/atta ... 1245010520 (http://www.aquaponics.net.au/forum/attachment.php?attachmentid=56&d=1245010520)
I'm considering this system for my next set up but i will definitely add an extra air pump.

badflash
01-28-2010, 02:58 PM
It can be done with one pump, but not the way you describe. If you use a large stock tank for the fish, be sure to paint the interior white so you can see the fish. I have rubbermaid tanks and it is tough to see the fish.

No reason to have a separate sump. You can put the fish in the bottom and the grow beds above. Flow rate should be about 1 turn over an hour minimum. That means if your tank is 300 gallons, you need a 300 gallon per hour flow rate. Design for double that as things don't always stay optimum. It doesn't hurt the fish to have the water level go up & down so long as they are left with enough water at the low point. If you have many beds, they won't cycle all at the same time, so the variation isn't likely to be all that much.

Grow bed volume should be about 2 times the tank volume.

Make all your plumbing easy to remove & clean. Do it now, or do it later. You'll do it, or give up.

dwaller
01-28-2010, 03:36 PM
@urbanrunoff
Thanks for the tips. I registered with the forum to see the link you sent, but I'm still in the "moderation queue".

@badflash
I got the idea of gravity fed beds here:

http://www.aquaponics.net.au/Chops.html

Basically using that setup except with loop syphons and no fingerling tank. Thank you for the time you took to post though, I am open to any and all suggestions, and since I haven't even purchased anything yet, I figured this is as good of a time to alter a half-cocked plan as any. I'm going to try and nail down more of the specifics of what I want to accomplish and then try and develop a strategy from there. I'll post back when I have more useful information.

JCO
01-28-2010, 03:55 PM
Welcome to the show....pull up an easy chair, relax and stay awhile. New voices are always a welcome addition to our family..! Whatever questions you have on you mind, this is the place to get the answers. :mrgreen:

davidstcldfl
01-28-2010, 03:57 PM
Hi dwaller.... :)

Great idea planning ahead.

badflash
01-28-2010, 07:51 PM
All I'm saying is that if you make the sump bigger, you can put the fish in the sump and forget the separate fish tank and fingerling tank. The only difference is that the fish tank does not maintain a constant level. Saves $$$ on a beginner system. You can always expand it. Nice thing about these systems is that they are pretty modular.


@urbanrunoff
@badflash
I got the idea of gravity fed beds here:

http://www.aquaponics.net.au/Chops.html

Basically using that setup except with loop syphons and no fingerling tank. Thank you for the time you took to post though, I am open to any and all suggestions, and since I haven't even purchased anything yet, I figured this is as good of a time to alter a half-cocked plan as any. I'm going to try and nail down more of the specifics of what I want to accomplish and then try and develop a strategy from there. I'll post back when I have more useful information.

wolfracer
01-29-2010, 09:04 AM
Hello, first time poster, short time lurker :)

1) I'd like to have the beds gravity fed, and only need to use a pump to take water from the sump back to the fish tank. Is this feasible?

4) I'd like to go low-power on the pump, and am thinking of going with a DC EL-SID10B12 pump, which runs off of DC. The downside to this, is that with a 30" lift, I'd be limited to about 2.5GPM flow.

After typing all of this out, I realized I'm really wishy-washy on all of this at the moment. I'd be open to any suggestions on what type of system to put in a 10x12 greenhouse.

I'm excited to get my system put together, thanks for any help I can get.

On number 1 this is exactly what I'm doing. Just make sure that you have the outlet of the fish tank high enough to feed to feed the growbeds and still have room for the sump under them. If I could go back and redesign mine, I would lift the fish tank another 4 " and use 3" feed line instead of 1 1/2".

On number 4 this is probably not enough pump. I use a liitle giant pond pump 380 gph runs at 35 watts and provides enough lift and volume to get the job done. If you are going to do the CHIFT/PIST type of system you wilso need a good tank over flow from the fish tank to maintain the fish tank level. I was shooting for the ability to move the volume of the fish tank every hour.

I fit all of what I am doing in a Harbor Frieght 10x 12 greenhouse. I have shutdown my riverbed system for a redisgn, current system is to susceptable to leaks and to hard to control flow. My original growbeds with loop siphons are still going strong!

Good Luck with your system Hope this helps!

jackalope
01-29-2010, 09:38 AM
dwaller, Welcome to the Forum, glad to have you on board!

dwaller
01-29-2010, 01:44 PM
In doing some more research, I think I like the idea that badflash suggested with eliminating the separate sump tank, and pumping from the fish tank up into the beds, then using bell siphons to feed back into the fish tank from the grow beds.

I've been looking at this pump:

Rule 25D Marine Rule 500 Marine Bilge Pump (500-GPH, 12-Volt)
http://www.amazon.com/gp/product/B000O8B7VO

It runs 12VDC@1.9A, which is right around the 23W draw mark. I'd like to find a 12VDC powered aerator so that I can run these devices off of a battery, which is charged by the grid. Any suggestions on this, or should I just submit to needing an inverter and take the hit on efficiency? Also, how many GPH should the aerator be able to handle and how often should it run?

I'll have more questions I'm sure, but this was on my mind at the moment.

Thanks for the welcoming responses.

jackalope
01-29-2010, 03:58 PM
Product Features

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Product Description
Product Description
Rule Submersible Bilge Pumps give you BIG value for your dollar! Rule submersible bilge pumps have set the standard for the industry for many years. They are the first choice of yachtsmen and commercial fishermen throughout the world. More innovations in bilge pump design have come from Rule Industries than any other manufacturer. Totally submersible; Compact, efficient, maintenance-free; Silent running, vibrationless; Exclusive Rule moisture tight Teflonseal; Ignition protected; Water cooled motor; No burn-out when run dry; Anti-airlock feature; Positive snap-lock strainer base. Order ONLINE Today! AVAILABLE SEPARATELY: Other Rule Submersible Bilge Pumps - word search in our Store for 'Rule Pumps'. Rule 500 GPH Pump... Keeps size and cost to a minimum. Same features as above. Permanent magnet motor. Stainless steel shaft. Ultrasonically welded housing for extra strength, eliminates leaks.

One thing it doesn't tell us is whether it is rated for continuous duty or not ....... that would be a concern for me, because a continuous duty motor might last longer, even if you are using it for F&D, on and off ;) For that price it sure beats the pants off the pond pumps available from Lowes or HD!

dwaller
01-29-2010, 05:14 PM
I think for the price, the are rated for intermittent duty. I still have to figure out the logistics of how to do the flood/drain with bell siphons. Do I put the pump on a timer to run for however long it takes to trigger the siphons, then have it turn off and wait for the beds to drain before turning it back on? How do I control the drain speed of the bed; use a smaller standpipe/siphon pipe combination, or just do a timed flood, then wait 10 minutes and flood again?

One question I can't seem to get my head around is if I have a 2'x6'x1' bed filled with ~14" of pea rock and flooded to 12", how do I figure out the volume of water that the bed will hold while taking into account the area the pea rock displaces? That brings another question; say I have 120 gallons in my fish tank, do I need to have that much, plus a certain amount for my beds that is always in the system? I'm really struggling with this one as I'm not sure how it will work if I pump most all of the water out of the fish tank all the time to fill the beds...

dufflight
01-29-2010, 05:47 PM
Not sure but 40% of gb volume for the water to fill it. Smaller pea gravel may make this less. I have 6000ltrs of media and have never worked out how much water goes to fill them.

badflash
01-29-2010, 05:51 PM
If you cycle the pump, you don't need a bell siphon, you just have to be sure that the timing allows the beds to flood fully and the flow must exceed the capacity of the drain. The beds need an overflow line as well as a drain in this case. With a DC sump pump that is rated for intermittant duty, this is a perfect thing. You just need a timer that will cycle as often as needed.

As far as DC air pumps, don't bother. Get a cheap inverter. 100 watt inverters are only $35.

dwaller
01-29-2010, 06:03 PM
hmm, ok. So, I would just put a slow-flow drain of some type on the beds, and put a timer on the pump to cycle as long as it takes to fill/drain? What type of timer allows for staggered timing? With a 500GPH pump, to fill a grow bed of the size I'm thinking (90 gallons without media), it will take roughly 4-5 minutes to fill., then probably 5-10 minutes to drain, and another fill cycle; or would it be best to do 5 minutes on, and 5 minutes off and tweak the drain rate so that it is drained in 5 minutes (if that's even possible)?

urbanrunoff
01-29-2010, 07:27 PM
how much do fluctuating levels (without a sump) affect the fish?
bell siphons scare me i think i will work with timers

badflash is def. right with visibility problems in a black tank. i have to block the flares with black plastic and use a diving flashlight be able to see in all the corners of the tank. :lol:

badflash
01-29-2010, 09:34 PM
The flood and drain times need to be determined by you. You need to experiment and not over think it. Turn on the pump and see how long it takes. Add 20% to account for bio-fouling. Make sure it stays drained for at least 20 minutes before it floods again.

Check my signature. These things are not automatic. You need to baby sit it. If you don't pay attention, it goes off the rails.

dwaller
01-30-2010, 08:12 AM
@badflash
That makes sense. I wasn't sure if someone had some magic to figure this out, or if I would have to use trial and error. In relation to the flood/drain cycle, I have a few questions:

1) If bell siphons are not needed with this setup, what would you recommend for a drain that is, I assume, adjustable?
2) What timer's are you guys using to control the flood/drain cycle; 12VDC if possible?

badflash
01-30-2010, 10:48 AM
I don't know of any DC timers, but I'm sure you will find them for marine use as boaters need them. Any timer that has removable pins can be set up with multiple on-off times. One flood & drain cycle every hour is normally good. The drain should handle about 1/4 of the pump flow, and the overflow must be able to handle 200% so you don't flood is the drain backs up. I would not use valves in the drain as they are a clog point. Be sure the pipes are easy to remove and clean as they WILL foul.

I would also provide some bio-filtration in the sump as there won't be any when the pump is off.

Put a screen around the pump so fish won't get caught in it.

dwaller
01-30-2010, 09:26 PM
Good to know. So doing some quick math here (bear with me...):

"The drain should handle about 1/4 of the pump flow" - (500/60)/4=2.08GPM pump flow

If my bed holds 40 gallons, it will take roughly 5 (+/-1) minutes to fill

"Make sure it stays drained for at least 20 minutes before it floods again." - 40/2=20 minutes to drain

Do I need to take the 20 minutes it will take the bed to drain and add another 20 minutes before flooding again; or does the 20 minutes it takes to drain the bed count?

This is all starting to come together in my head better, I appreciate all the input I'm getting here.

badflash
01-30-2010, 10:06 PM
I don't believe the dry time is all that important, but I've not experimented. The key is that the roots get air and don't dry out. I've seen folks that only flood 4 times a day, so it isn't a big deal from the plant side. Fewer floods means a longer time for build up in the fish tanks, so try to keep total cycle time at under an hour.

dwaller
01-31-2010, 07:24 PM
In reference to the ammonia build-up in the FT.. I've read that some people do a 50% change on their water every once in a while, is that because the water has built up to a point that the plants can't keep up?

I've also read that getting oxygen in your water helps break down the ammonia; would it help to run the aerator 24x7, or would that be overkill. And as a side to that question, is it ok to only run the aerator 15 minutes on and 45 minutes off, or does the change in noise hurt the fish at all?

jackalope
02-01-2010, 10:09 AM
In reference to the ammonia build-up in the FT.. I've read that some people do a 50% change on their water every once in a while, is that because the water has built up to a point that the plants can't keep up?

I've also read that getting oxygen in your water helps break down the ammonia; would it help to run the aerator 24x7, or would that be overkill. And as a side to that question, is it ok to only run the aerator 15 minutes on and 45 minutes off, or does the change in noise hurt the fish at all?

I do a 50% water change once a week because theammonia builds up so fast in one of my tanks, and I have a terrible problem with filamentous algae (probably from the Spring water I use). Also, I run several aeration devices (air stones, power filters, etc., and it doesn't seem to slow down the production of the ammonia at all. In the tank that I have the most fish in, I have a home-built bio-filter, which is working great!, so I only add water (about 5 gallons per week) to replace water loss due to evaporation.

dufflight
02-01-2010, 02:22 PM
I checked my system yesterday. Mainly cos I haven't tested in a couple of months.
Am 0 Ni 0 Na 10

How big are you gb's. Am at zero is the norm for most AP systems. I have to dose mine to get a reading and it does not last long.

Breed
03-05-2010, 10:55 AM
I hear all these great ideas on designs - but I need to know is how do I keep my fish warm. I live in Missouri and it doesn't get warm weather till May. I wanted to put my Tiliapia out in the tanks outside by May 1st but it's still cold at night. Anyone have any ideas on a heater???? My tank is 8' in diameter and 3' deep

jackalope
03-05-2010, 11:09 AM
I hear all these great ideas on designs - but I need to know is how do I keep my fish warm. I live in Missouri and it doesn't get warm weather till May. I wanted to put my Tiliapia out in the tanks outside by May 1st but it's still cold at night. Anyone have any ideas on a heater???? My tank is 8' in diameter and 3' deep

Perhaps the stock Tank heater that badflash has recommended in several threads (see this thread) Clik ;) (http://www.diyaquaponics.com/forum/showthread.php?251-Heaters) Is that an 8' round tank? How many gallons do you reckon it is?

stucco
03-05-2010, 11:37 AM
I would start with a greenhouse to hold the heat in. that way you are not loosing water to evaporation and throwing money away trying to keep that much water warm outside.

dufflight
03-05-2010, 02:10 PM
Some people use black pipe to heat up 200ltr drums of water inside the greenhouse. The heat helps of a night. While looking at biochar and the temps that it gets to I wondered how much water it could heat while making biochar. Then again I have a wood fire inside and could probably hook up a heat exchange to it. Some even come with the piping to heat a houses hot water.

preasons
08-30-2010, 04:21 PM
New question. Are any of you growing your on fish food. I have heard water lettuce, and duck weed are good feeds for talipa. If so, does it grow well in AP and does it provide sufficient nutrients.

badflash
08-30-2010, 06:02 PM
My tilapia hate water lettuce. They eat the duck weed just fine. I've seen reports that it had too much water to be a meaningful food unless dried and pelleted.