[APD] Fw: Re: Ph controllers (was Re: CO2 System)

[Cynthia Powers <mscyn at earthlink_net>]

-----Forwarded Message-----
From: Russell Vance <russell_vance at gmail.com>
Sent: Nov 19, 2005 9:45 AM
To: "aquatic-plants-owner at actwin_com" <aquatic-plants-owner at actwin_com>
Subject: Re: [APD] Ph controllers (was Re: CO2 System)

You got that backwards. They are normally closed and the controller turns
the solenoid on (open) when the pH gets above the set point, and turns off
(closes the solenoid) when it gets below the set point.


If it turned on when it got below a set point, it would turn the co2 on,
thus lowering it more, then it would never turn off.


On 11/19/05, S. Hieber <shieber at yahoo_com> wrote:
> >
> > A pH controller turns on/off whatever device you attach to
> > it. Fo aquatic gardening purposes, they are normally open
> > circuit when the pH is above a set point and closed (or ON)
> > when the pH is below a set point. If you connect a solenoid
> > to the controller, CO2 will flow only when the pH is below
> > the controller set point and then will shut down when the
> > pH is above set point.
>
>
>
>

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