Re: Aquatic Plants Digest V2 #471

>From: Neil Frank <nfrank at mindspring_com>
>Date: Thu, 23 Jan 1997 06:43:32 -0500
>Subject: Re: ich and other conclusions
[controls, common sense, the test of time]
>On the other hand, if the same person talked said that they had
>multiple tanks - some with and some without heating coils -  (everything
>else equal) - and they discussed the status after 1 year, 2 years etc
>(similar to what George and perhaps other people have done); then the
>comment would be meaningful.


{I hate 'me-too' posts, so I'll seek solace in religion)


>From: Lyndle Schenck <LSCHENCK at dcscorp_com>
>Date: Thu, 23 Jan 1997 08:59:17 -0500
>Subject: Aquatic Plants Digest V2 #470 -Reply

>I guess I need to be more precise with my technical writing skills.  The
>implication was that some of these low voltage transformers are
>designed for underwater lighting in ponds, fountains, etc. and some are
>designed for above water low voltage lighting, e.g. sidewalk or deck
>lighting.  The transformers designed for lights that are submerged are
>several times more expensive and I can discern no difference in their
>construction other than an integrated GFI circuit breaker.  In either case
>the transformer must be located in a dry location.

I don't see why they need to be more expensive. Maybe it's the
aquarium store syndrome (a 100 pound bag of pea gravel is 7 dollars,
the aquarium owner conveniently re-bags this and charges $10/lb)

>On another issue.  Someone suggested using an ac source from a
>switching transformer.  I suspect that the power source is less important
>than the care taken to shield/water proof/ground the components.  For
>safety concerns I would be very reluctant to employ ac in an aquarium
>where there is ANY chance of a current leak. (The voltage is not as
>critical as the current)  Try to open up a power head to see the lengths
>manufacturers go to waterproof their products.

AC is a little more lethal than DC at the same voltage and current.
But I agree about the care in construction being more important.
A switching supply is more efficient for UGH, but is it worth $100

BTW, manufacturers don't necessarily go out of their way in
constructing aquarium products. I've had powerheads that fail and leak
current after a few months, heating tubes that leaked and whose coils
became rusty after a year or two.

I think most manufacturers are happy if their product works out of the
bag and thereafter for a few months. Anything more than that is being

Personally, I build things DIY for the long-haul. That is, if
something I build breaks in my lifetime I'm incredibly disappointed.

>From: hermel at ibm_de
>Date: Thu, 23 Jan 1997 16:21:43 +0100 (NFT)
>Subject: CO2 bottle pressure gauge
>Hi, sometime ago there was a discussion on the list concerning the usefulness 
>of CO2 pressures gauges measuring the pressure of the CO2 bottle to be able to
>detect early if the bottle is empty. I think the consensus was that because
>CO2 is a liquid in the bottle under the high pressure the gauge would show
>full pressure almost until the bottle is empty and then fall within several

Right, more or less. In the last 5 years or so, I've bought 7 or 8
20 pound CO2 tanks. Each showed the exact same pressure (about 1200
psi) and then, over a few days or a week, dropped to 0. As soon
as that needle moves, the tank is empty - you're running on fumes.

>However, I had to adjust the output pressure of the regulator more often 
>recently. Strange thing was that the output pressure was increasing more and
>more. Any explanation for this?

Maybe dust? When you get a new tank - open it for a second and let it
blast away - that removes any dust. Then re-connect it to your system.

A handy extra feature is a coupler called a "snubber" which has a
metal plate with very tiny holes. It is designed to reduce pressure
surges, but also makes a good dust filter. It is installed between the
tank and the regulator. You can get it from a good plumbing supply
store. Physically it looks like solid metal, but if you had 1200 psi
at one end and 50 psi at the other, you don't need very big holes...

>From: George Booth <booth at hpmtlgb1_lvld.hp.com>
>Date: Thu, 23 Jan 1997 08:33:06 -0700
>Subject: Re: UGH Transformers
>From: Jim Hurley <hurleyj at arachnaut_org>
>Date: Wed, 22 Jan 1997 23:01:50 -0800
>>>After talking to a few transformer suppliers I have concluded that
>>>finding a transformer that does not have the primary and secondary
>>>windings on the same core is just not practical.
>> I have never use undergravel heaters, but I don't understand this
>> issue.
>When Uwe Behle posted the original DIY heating coil article, he
>mentioned that the safest transformer has the primary and secondary
>windings on separate bobbins.  Some transformers have the primary and
>secondaries wound on the same bobbin or wound on the same metal core.
>There exists the potential for the insulation of the wires to be
>breached, thus connecting the primary directly to the secondary and
>feeding 110v into your tank.  
>Personally, I don't think this is a problem.  Use a good quality
>transformer and don't pound on it with a hammer.  Or, if you're
>paranoid, buy a Duplamat for about $300; for that price, it's probably
>pretty safe.

One cheap way to isolate transformers is to use three cheap ones in
series. For example - say I want 24v at 3 amps. I buy three 24 VAC
transformers and put them in series. The first reduces 120 VAC to
24 AC. The second has the secondary connected to the first's primary
so it steps up the 24 VAC to 120 VAC. The third steps this back down
again to 24 VAC.

This is very inexpensive and will provide pretty good isolation from

The safest way would be to buy car batteries and a recharger.

Jim Hurley        mailto:hurleyj at arachnaut_org
<URL: http://www.webcom.com/hurleyj/home.html>