Re: Aquatic Plants Digest V2 #308

Aquatic-Plants-Owner at actwin_com wrote:
> Aquatic Plants Digest      Friday, 8 November 1996      Volume 02 : Number 308
> In this issue:
>         Lights and condensation covers.
>         Watts vs. Lumens
>         RE: Watts vs. Lumens
>         RE: Aquatic Plants Digest V2 #307
>         Lighting
> See the end of the digest for information on subscribing to the
> Aquatic Plants mailing list and on how to retrieve back issues.
> ----------------------------------------------------------------------
> From: mtn at delarue_demon.co.uk
> Date: Fri, 08 Nov 96 10:04:26 GMT
> Subject: Lights and condensation covers.
> I've made my own lighting fixture for fluorescent tubes using plastic guttering,
> the guttering is semicircular in cross section and just about the right size to
> cover the bulbs. The light fixture rests on top of the tank and overlaps either
> side by about 1 inch. Between the light fixture and the water surface I also
> have a cheap clear plastic condensation cover. To try and improve light
> penetration I intend to remove the condensation cover so there is nothing
> between the lights and the water surface (approx. 1 or 2 inches below). I think
> this is a fairly standard practice so some of you will already be doing it,
> however I still have a couple of concerns:
> 1. Is it possible for moisture build up in the end caps of the lights to causes
> problems? I am really thinking about moisture building up during the night so
> that when the timer turns on the lights in the morning it could trip the RCD (I
> think these are GFIs in the US).
> 2. I have clumsy pl*c, (too clumsy for a plant tank!) and I was wondering if she
> might cause problems by splashing the bulbs occasionally.
> Anyone been down this road?
> Mick
> ------------------------------
> From: jphealy at SYSCONN_COM
> Date: Fri, 8 Nov 1996 09:42:52 -0500
> Subject: Watts vs. Lumens
> I am baffled. There have been several posts saying that using Wattage
> as the basis for measuring lighting is a crock. I am sure this is true.
> However, each of these posts then goes on to describe the writer's
> lighting in terms of Watts (snip)

Although watts is what many of us use when describing some of our lighting
applications, lumens and CRI ratings would be the best way to describe what
we are doing.  I have found that a pair of 48" T-8 tubes with a lumens rating of
3700 and a CRI rating of 90+  work well on my 75gals, while four tubes work
exceptionally well on my 120gal.  I rewired All-Glass twin tube fixtures with
electronic ballasts because of their nice appearance and inner reflectors.

The manufacturer of the tubes I use claims that they will lose 10% of their
intensity in 30 months.  While I'm not totally willing to believe that, I have
had them in use now for almost a year and everything "looks good".  Until I
have a good reason, I don't think I'll change them, at least for another six
months.  I'm sure others have heard similar claims about these tubes.

Karl R. Schoeler