Re: [APD] Solenoids & Needle Valves

[Paul M Wallace <pwallace at u_washington.edu>]

You can play with a calculator here:
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

If you are runing CO2 24/7, measure pH before and at the end of the photoperiod to determine your pH swing.

Now with a controler and solenoid, if you KH is 6 degrees, a change of .2 would result in:
pH 6.5  -->  57 ppm CO2
pH 6.7  -->  36 ppm CO2

It is quite possible to turn the gas off at night, I know there would be a few morings I would forget to turn it back on.  The flow rate is often slow enough that it might take hours for the regulator to bleed down to 0 if the CO2 tank is turned off.  It can also be difficult to set the flow rate if you turn the needle valve...  So the solenoid is a set and forget option.

I can think of three reasons to get the controler: A) soft water (KH <3?) which could quickly crash to low pH. B) End of tank dump that also crashes pH.  C) Gaget envoy.

Otherwise set the bubble count low, then slowly increase every few days until plant growth goes explosive.  I am starting to think Tom Barr is right in that better results are obtained by "reading" a tank than a mechanical insistance on test kits etc...   I still have no idea about the CO2 mist, but that is another email.

-Paul

On Wed, 28 Sep 2005, urville wrote:

> couple things here. without co2 my water is 7.6 with it it's more like 6.6 is the rate so low that it wouldnt change by more than .2?
>
> This is waht I dont get about a solenoid. if id ont have one and want to save co2 by having it off at night. until i can get a solenoid why dont i just turn the vavle on top to shut off the gas?
> is this not possible once hooked up or something?
> Ian
>
> -----Original Message-----
> From: "S. Hieber" <shieber at yahoo_com>
> Sent: Sep 28, 2005 3:50 PM
> To: aquatic plants digest <aquatic-plants at actwin_com>
> Subject: Re: [APD] Solenoids & Needle Valves
>
> I would recommend a needle valve for any compressed gas
> set-up where you don't want the flow to exceed a certain
> for whatever reason, such as, killing all your fish.
>
> A solenoid is optional. You can run without one and you'll
> use up CO2 more quickly than if you had a solenoid
> connected to the lights timer. If you can find inexpensive
> but reliable solenoids, the savings in CO2 can offset the
> cost of the solenoid over time. With a solenoid on a timer
> but no controller, you rely on relatively stable pressure
> and the needle valve to maintain your CO2 levels ()which,
> of course will dip at night when the solenoid is off, but
> be relatviely stable oduring lights-on. With no solenoid,
> you rely on the neeedle valve setting and the pH goes up a
> bit at night and declines during the day.
>
> A controller is the most expensive and least useful, though
> some of us will use them on a tank or two if for no other
> reason than to see what happens ;-) .
>
> With any of these methods, the pH swing needn't be more
> than about 0.2 units, which is an insiginificant amount for
> most aquaria. It doesn't hurt the fish or plants forthe CO2
> to run 24-7; it doesn't hurt for the CO2 to turn off at
> night; it doesn't hurt for the CO2 to go off an on several
> times as the controller trip points are it.
>
> So it's really a question of your own convenience and up
> front versus long costs.
>
> have plants, have fun,
> sh
>
> --- urville <urville at peoplepc_com> wrote:
>
>> I notice alot of Co2 systems dont come with a needle
>> valve. And i mean even when they are called complete
>> deluxe systems. Why is this? Are they not as important as
>> I had been led to believe? And wil any needle valve do? I
>> see alot of different kinds some for different gases.
>>
>> Last but not least. is there a definitve answer as to
>> whether you need a solenoid. I see that ph controllers
>> are optional. and in my tank with a constant bubble rate
>> I cant ever see needing one, but the solenoid issue, I
>> cant seem to find an argument for or against them that
>> gives any real world proof either way.
>> Anyone, Anyone? Bueller, Bueller, Bueller.
>>
>> hehe sorry
>> Ian
>>
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