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Re: Jim Kelly's vermiculite recipe
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To: Stephen.Pushak at hcsd_hac.com
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Subject: Re: Jim Kelly's vermiculite recipe
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From: "shaji (s.) bhaskar" <bhaskar at bnr_ca>
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Date: Fri, 9 Jun 1995 08:02:00 -0400
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Cc: aquatic-plants at actwin_com
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In message "Re: Jim Kelly's vermiculite recipe", Steve Pushak writes:
>Yes, that is a good point. My plan is not to use a powerhead of any sort but
>rather only about 1-5 cm of hydrostatic pressure. I hope that will be sufficient
>to induce a suitably low flow rate as per the heating coil method. I think I
>should be able to alter the hydrostatic pressure by the height of a tube which
>receives the outflow from a filter or pump. (drill holes whatever) I will post
>this on the list and hope for additional comments. Does anyone have any idea
>of how much hydrostatic pressure would be ideal or the ideal velocity of water
>being transported through the substrate or a method for measuring this? The
>flow rate should be dependent only upon hydrostatic pressure differential, the
>thickness of the substrate and it's liquid permeability. Sounds like data we
>should be able to discover from soil lab research.
I don't know whether a 5 cm head of water will be enough to provide
adequate circulation, and I don't know what the ideal rate of
circulation is, either :-(. I do have a suggestion for determining
the total rate of flow. You drip water into the intake at a constant
rate. And wait till the level water stabilizes. Then measure the
height of the water column and the rate of inflow of water. You could
create a nice graph showing the variation of flow rate with water
column height.
>Is everyone still getting the mailing list except me? The last one I
>got was 108.
Works like a charm for me, and nobody else has complained. I am also
getting regular email from the server promising me that everything is
under control. I'll try unsubscribibg and resubscribing you.
-Shaji
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Shaji Bhaskar bhaskar at bnr_ca
BNR, 35 Davis Dr., RTP, NC 27709, USA (919) 991 7125