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Re: [APD] plexi lid vs glass?
Plexiglass absorbs less light but much more water than does
glass. The result is that the wet side expands, causing the
plate to warp and curl. However, after the lights heat up
the plexiglass and dries it out, it tends to flatten again.
Personally, I don't worry mcuh about the amount of light
lost through a glass or plastic cover. The amount changes
over time with any scaling or etching that occurs, and the
bulb degrades over time too. You can run the bulbs a little
longer to compensate, assuming you're running them for only
about 10 hours or so per day to begin with. Or you can
start out with a little bit more light than you might
otherwise figure -- or you can start out with a lot more
light but keep some bits of Ceratopteris cornuta (water
sprite) floating around the surface to act as a light
buffer -- the amount of T. cornuta is easily adjusted ;-)
with pruning -- or you can just accept the amount of light
you get with the set up. If the plants aren't asking for
more light, I wouldn't let the math override their
contented silence ;-)
Scott H.
--- Kelleen Harris <kelleen_harris at csumb_edu> wrote:
> Hi, you guys have been discussing how much light is lost
> through glass. That is good to know. Anyone know if more
> or less is lost through a 0.25 inch piece of plexi from
> Home Depot? I friend of mine added this to his tank and I
> was considering doing
> it also. I have so much evaporation with an open top.
> Thanks,
> Kelleen Harris
>
> aquatic-plants at actwin_com on Tuesday, September 20, 2005
> at 9:00 AM wrote:
>
>
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> >than "Re: Contents of Aquatic-Plants digest..."
> >
> >
> >Today's Topics:
> >
> > 1. Rubins (Richard J. Sexton)
> > 2. Light and Lids (Rachel Sandage)
> > 3. Re: putters and gruntlements (RMGTBTS at aol_com)
> > 4. Re: Light and Lids (Mariano F. Bonfante)
> > 5. Re: Light and Lids (Jerry Baker)
> > 6. Re: Aquatic-Plants Digest, Vol 25, Issue 57 (Jerry
> Baker)
> > 7. Re: Alternatives to watt/gallon rule (Andrew
> McLeod)
> >
> >
>
>----------------------------------------------------------------------
> >
> >Message: 1
> >Date: Tue, 20 Sep 2005 09:02:03 -0400 (EDT)
> >From: "Richard J. Sexton" <richard at aquaria_net>
> >Subject: [APD] Rubins
> >To: aquatic-plants at actwin_com
> >
> >
> >>Have you tried Rubins?
> >
> >Yeah but they made me itch. I'm going back to briefs.
> >
> >
> >
> >--
> >
> > /"\ / http://lists.aquaria.net
> > \ / ASCII RIBBON CAMPAIGN / Killies, Crypts,
> Aponogetons
> > X AGAINST HTML MAIL / http://new.killi.net
> > / \ AND POSTINGS / http://images.aquaria.net
> >
> >
> >
> >------------------------------
> >
> >Message: 2
> >Date: Tue, 20 Sep 2005 06:19:15 -0700
> >From: Rachel Sandage <rachelsor at gmail_com>
> >Subject: [APD] Light and Lids
> >To: aquatic plants digest <aquatic-plants at actwin_com>
> >
> >One question I have is if all these light measurements
> and stuff take into
> >account any glass or acrylic cover which might be on the
> tank? Standard tank
> >cover glass is probably pretty bad at transmitting light
> - no extra-low
> >dispersion glass, no anti-reflective coating, standard
> green soda glass. Has
> >anybody ever done studies to show how much light is lost
> in the lid?
> > My husband enjoys these discussions mightily, since he
> is an active amatuer
> >astronomer, which is all about light gathering
> capabilities. They spend some
> >time on their lists discussing how best to get light
> from place (star) to
> >place (eye) too.
> > Rachel
> >
> >
> >------------------------------
> >
> >Message: 3
> >Date: Tue, 20 Sep 2005 10:00:00 EDT
> >From: RMGTBTS at aol_com
> >Subject: Re: [APD] putters and gruntlements
> >To: aquatic-plants at actwin_com
> >
> >scott
> >
> >i would write a response but i can't see the screen
> because of the tears in
> >my eyes from laughing so hard.
> >
> >tks you made my day
> >
> >rich green
> >milton ma
> >
> >
> >------------------------------
> >
> >Message: 4
> >Date: Tue, 20 Sep 2005 14:18:57 +0000
> >From: "Mariano F. Bonfante"
> <mariano_bonfante at hotmail_com>
> >Subject: Re: [APD] Light and Lids
> >To: aquatic-plants at actwin_com
> >
> >With a luxometer I messured 11% loss. The same value was
> obtenied with 3 mm
> >to 6 mm glass.
> >
> >Mariano
> >
> >
> >
> >>From: Rachel Sandage <rachelsor at gmail_com>
> >>Reply-To: rachelsor at gmail_com, aquatic plants
> digest
> >><aquatic-plants at actwin_com>
> >>To: aquatic plants digest <aquatic-plants at actwin_com>
> >>Subject: [APD] Light and Lids
> >>Date: Tue, 20 Sep 2005 06:19:15 -0700
> >>
> >>One question I have is if all these light measurements
> and stuff take into
> >>account any glass or acrylic cover which might be on
> the tank? Standard
> >>tank
> >>cover glass is probably pretty bad at transmitting
> light - no extra-low
> >>dispersion glass, no anti-reflective coating, standard
> green soda glass.
> >>Has
> >>anybody ever done studies to show how much light is
> lost in the lid?
> >> My husband enjoys these discussions mightily, since
> he is an active
> >>amatuer
> >>astronomer, which is all about light gathering
> capabilities. They spend
> >>some
> >>time on their lists discussing how best to get light
> from place (star) to
> >>place (eye) too.
> >> Rachel
> >>_______________________________________________
> >>Aquatic-Plants mailing list
> >>Aquatic-Plants at actwin_com
> >>http://www.actwin.com/mailman/listinfo/aquatic-plants
> >
> >
> >
> >
> >------------------------------
> >
> >Message: 5
> >Date: Tue, 20 Sep 2005 08:08:43 -0700
> >From: Jerry Baker <jerry at bakerweb_biz>
> >Subject: Re: [APD] Light and Lids
> >To: aquatic plants digest <aquatic-plants at actwin_com>
> >
> >Mariano F. Bonfante wrote:
> >> With a luxometer I messured 11% loss. The same value
> was obtenied with 3 mm
> >> to 6 mm glass.
> >
> >I do believe that nearly all of the loss with glass
> occurs due to
> >reflection at the physical boundaries (i.e., the
> interface between air
> >and glass). No matter how thick the glass is within a
> normal range found
> >on an aquarium, the loss will be the same. I always
> understood that
> >about 7% was lost at each surface with normal uncoated
> glass. Seems like
> >if that was the case, a lid would be predicted to lose
> about 13.5%, but
> >that's not far out from what you measured.
> >
> >--
> >Jerry Baker
> >
> >
> >------------------------------
> >
> >Message: 6
> >Date: Tue, 20 Sep 2005 08:11:38 -0700
> >From: Jerry Baker <jerry at bakerweb_biz>
> >Subject: Re: [APD] Aquatic-Plants Digest, Vol 25, Issue
> 57
> >To: aquatic plants digest <aquatic-plants at actwin_com>
> >
> >S. Hieber wrote:
> >> Of course, it's more a matter of personal preference
> than
> >> "proper" amount. In fact, I know a few folks that do
> about
> >> 1.0-3.2 putters per gallon per week and love every
> minute
> >> of it. Their gruntlement has reportedly reached as
> high as
> >> 10-12 grunts-of-pleasure per day, which equates to
> >> 34.4-41.28 smiles per week -- of course that's C-scale
> >> weighted for solitary activity. On the A-scale,
> weighted
> >> for group activity, the numbers would be even higher.
> >
> >Dude! You forgot the introverted-extroverted exponent on
> the A scale,
> >which would make the numbers lower for group activity :?
> >
> >--
> >Jerry Baker
> >
> >
> >
> >
> >------------------------------
> >
> >Message: 7
> >Date: Tue, 20 Sep 2005 16:37:19 +0100
> >From: "Andrew McLeod"
> <thefish at theabyssalplain_freeserve.co.uk>
> >Subject: Re: [APD] Alternatives to watt/gallon rule
> >To: "aquatic plants digest" <aquatic-plants at actwin_com>
> >
> >On Mon, 19 Sep 2005 22:43:28 +0100, Jerry Baker
> <jerry at bakerweb_biz> wrote:
> >
> >> I have often wondered about applying an infrared
> blocking film to a
> >> shield in extreme cases of MH lighting heating up a
> tank.
> >
> >Probably a really, really bad idea BTW...
> >Firstly, the 'heat' that seems to come from a bulb may
> not just be infrared radiation - all radiation (including
> visible light) will warm things up if they absorb it
> (i.e. they are not white/reflective).
> >Secondly, if MH's do put out a fair amount of infrared,
> then an infrared filter will have to absorb all of that
> radiation - as heat. So if it's enough to warm up your
> tank, think what it will do to a little bit of film...
> >
> >--
> >Andrew McLeod
> >thefish at theabyssalplain_freeserve.co.uk
> >
> >This email was scanned carefully before transmission to
> remove any content, information or relevance.
> >
> >
> >------------------------------
> >
> >_______________________________________________
> >Aquatic-Plants mailing list
> >Aquatic-Plants at actwin_com
> >http://www.actwin.com/mailman/listinfo/aquatic-plants
> >
> >
> >End of Aquatic-Plants Digest, Vol 25, Issue 61
> >**********************************************
>
>
> Kelleen
>
> Central Coast Watershed Studies
> Phone: (831) 582-5217
>
>
>
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