Aquaponics Digest - Wed 03/04/98 





Message   1: Re: Grow Beds/Ratios
             from "Lloyd R. Prentice" 

Message   2: Re: Grow Beds/Ratios
             from S & S Aqua Farm 


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Subject: Re: Grow Beds/Ratios
From:    "Lloyd R. Prentice" 
Date:    Wed, 04 Mar 1998 09:34:17 -0500

S & S Aqua Farm wrote:
> 

> 
> We recommend 1:2 ratio as the most productive in both sides
> of the system.

Just to confirm my understanding, is the following analysis of a
proof-of-concept system correct?

Tank: 20 gallons
Beds: 40 gallons (4' x 3' x .5' filled with pea gravel)

Can support up to 10 1 lb. fish (Assuming 1 1b fish/gallon).

Questions:

-- How do you size the pump?
-- With beds filled with gravel, how much water would be pumped out of
the tank when the pump fully charges the beds?

Many thanks,

Lloyd


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Subject: Re: Grow Beds/Ratios
From:    S & S Aqua Farm 
Date:    Wed, 04 Mar 1998 15:01:55 -0600

At 09:34 AM 3/4/98 -0500, Lloyd Prentice wrote:
>S & S Aqua Farm wrote:
>> We recommend 1:2 ratio as the most productive in both sides
>> of the system.
>

>Just to confirm my understanding, is the following analysis of a
>proof-of-concept system correct?
>
>Tank: 20 gallons
>Beds: 40 gallons (4' x 3' x .5' filled with pea gravel)

This is approximately the grow ratio of water to grow beds we use and
recommend.  20 gallons of water would represent almost 3 cu. ft., with a
4'x3'x.5' bed filled with gravel would be approximately 6 cu. ft., if filled
to the top.
>
>Can support up to 10 1 lb. fish (Assuming 1 1b fish/gallon).

We generally do not recommend this volume of fish/gallon.  For our system we
stay closer to 1/2 lb./gallon, with 3/4 lb. as a maximum.

Tom's comment is that 1# fish would react poorly to this small volume.  If
you're actually using this size aquarium, remember that the smaller the
system the more delicate the balance will be.


>Questions:
>
>-- How do you size the pump?  

For our 800-1000 gal. tanks, we use 1/2 hp pumps.  Pump size may dictated in
some locations by availability.  Rainbow akes a number of small pumps
frequently used in aquariums and hydroponics.  

Tom's suggestion is to use the largest feasible to reduce pump running time,
and also to provide aeration in the return water system.

>-- With beds filled with gravel, how much water would be pumped out of
>the tank when the pump fully charges the beds?

Tom feels this size bed would hold about 3-4 gallons of water at saturation.

Pete Theisen has had more experience with operating a system of the size you
describe, and I hope he'll be able to take time to comment on it.  I could
repost some of his earlier communications if you're actually planning a
system of this size, not just finding a base point.

Paula
S&S Aqua Farm, 8386 County Road 8820, West Plains, MO 65775  417-256-5124
Web page  http://www.townsqr.com/snsaqua/

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