Hi Ray & John,
Let me please try to clear up the info being discussed here and apologize ahead of time if I miss anything either of you has directed to me in way of questions... it is sometimes difficult when the questions span multiple posts and I have the inability to track each one as I reply.
For starters, Lumen is the measure of the human eye's perception of light and plays no bearing on the growth of plants or corals. Lux is also a measurement of light perceived by the human eye. Wattage is the energy consumption used to power an electrical device, and PAR (Photosynthetic Active Radiation) measures the level of useful radiation given off by a light source used in photosynthesis. (sorry for the vocab lesson but I felt this important to clarify) So, when trying to determine how much useful light any bulb will provide for any situation, it is actually PAR that matters most.
John, you mentioned that you have noticed the differences in the brightness of the new bulbs vs old bulbs, and while this is accurate, it is the degradation of PHOSPHORS that is responsible for shift of spectrum while also reducing the amount of brightness and reducing the amount of PAR. Ballasts also weaken over time (years) and eventually need to be replaced to be as effective as a new fixture. It is the ballast that is responsible for the amount of power any bulb is going to give out. An old ballast will not provide the same amount of useful light as a new ballast, even if the bulbs are identical.
I'd also like to add that not every new ballast of the same make & model gives off the same exact amount of power. There is an industry standard for what is called "ballast factor", which is the amount of power each individual ballast puts out. The standard ranges from approximately 95%-100%. The manufacturers do not test every individual ballast for ballast factor... they may test maybe 10 out of 100 from each lot produced. So essentially you can have 2 seemingly identical ballasts and one of them gives off 95% of the power while another gives off 100% of the power, so side by side one will drive slightly more wattage to the bulb than the other and they can be slightly different in lumen, but so slight the human eye can't tell the difference. This applies to all fluorescent fixtures.
In regards to the T5 vs T8 and their heat output... the difference is so slight that it is usually not noticed in any measurable amount, however, the strength of a T5 light vs a T8 will make a difference in regards to plant (or coral) growth.. especially in regards to algae growth in a shallow tank, which is why I suggested sticking to the T8 for the smaller, shallower 10 gallon. If this were a taller tank, such as a 20 high, then I would agree that a T5 would be the better option. Due to the shallow depth of a 10 gallon tank I suggested the T8 be the better way to go to avoid algae issues, because the temp difference is so slight that the T8 isn't going to raise the water temp anymore than a T5 will, and because put simply, the amount of light needed to grow plants or most corals in a 10 gallon tank just doesn't warrant the expense of a T5 fixture for something this shallow.
Cost difference between the 2 fixtures is quite a bit, so why suggest a more expensive fixture if it's not truly needed? Like anyone else, I enjoy saving money where I can in this hobby, and to suggest someone spend all that extra money and risk problems with algae blooms needlessly makes no sense to me.
Dawn
--- In AquaticLife@yahoogroups.com, sevenspringss1@... wrote:
>
> Hi Dawn,
>
> Yes, these screw-in fluorescent bulbs are a type of compact fluorescents
> (CFL's). They're the latest in energy saving innovations made to replace
> the normal incandescent bulbs in household ceiling fixtures and lamps, etc.
> A CFL bulb producing the equivilent amount of light of a 60 Watt
> incandescent bulb uses only 13 Watts though, so it doesn't produce the amount of heat
> you're probably thinking of. It's advertised to use 75% less energy than
> "ordinary" bulbs. It does still get hot though, but unlike an incandescent
> bulb with which you'd get burned if you tried to touch it while it's
> working, you can actually hold one of these smaller wattage CFL bulbs while it's
> working without risk of being burned.
>
> Still, I agree with you that to avoid unnecessary heat (especially in the
> Summer), that a hobbyist would be better off using a T8 fluorescent bulb --
> for a smaller (shallower) tank -- and probably a T5 for the deeper tank for
> normal aquarium illumination. I don't know if one produces much more heat
> than the other, as John is suggesting, although just one 18" (18 W) T8
> tube for a 10 gallon tank is often not enough light for growing medium-light
> requiring plants like Amazon Swords. When dealing with fluorescent bulbs,
> the lumens really need to be considered rather that the wattage -- in
> addition to the "temperature" (Kelvin) for the plants' needs -- and I don't know
> what 18 Watts of fluorescent lighting equates to in lumens. I wouldn't
> think though, the difference in heat produced by these two tubes wouldn't be
> all that great, unless John has cause to explain differently, but either one
> has to be so much better in reducing heat than an incandescent, and still
> better than a CFL.
>
> Ray
>
>
> In a message dated 7/5/2013 5:44:56 A.M. Eastern Standard Time,
> dawnshungryeyes4u2c@... writes:
>
>
>
>
> One thing I would like to point out here is that the depth of the tank has
> a lot to do with choice of "proper" lighting needs regardless of what
> animals/plants you are keeping. This being a 10 gallon tank which is shallow,
> T5 lighting would be quite strong for such a small tank, so be careful not to
> over light the tank. Not only will too much lighting contribute to algae
> growth but it can also affect animals in saltwater situations and plant
> growth in freshwater situations.
>
> Not knowing what you are keeping in this tank, I am still going to suggest
> standard fluorescent lighting to you simply due to the depth of your tank.
> For freshwater, standard T8 fluorescent lighting is strong enough to grow
> Amazon swords, which is a plant that requires high light, and is also
> strong enough for saltwater to grow anything but things such as some of the SPS
> corals that require very high lighting.
>
> Because T8 is sufficient to grow almost anything in that size of a tank,
> jumping up to T5 lighting would be overkill in my opinion, and would likely
> cause more harm than good as an end result. Standard T8 lighting can work
> well over any type of cover and will fight right over the standard deluxe
> hood the same way the incandescent fixture does now.
>
> The "screw in fluorescent" bulbs that I heard mentioned in this thread are
> something else I have to question. This sounds like compact fluorescent
> bulbs to me, and that is another I would avoid because CF lighting can put
> out a great deal of heat as well... much more so than incandescent. For that
> reason I would avoid those since that would simply add to your current
> problem rather than resolve it, and has the potential to melt the plastic of
> your deluxe hood/cover that you are currently using. There are some
> situations where CF lighting can work great... but over a 10 gallon tank... not so
> much.
>
> Also to clarify the info I posted earlier about the quality of LED
> fixtures... there are a few on the market that are excellent, but the cost for
> them would make no sense if standard fluorescent will resolve your problem and
> suit your needs. You would be talking about a difference of anywhere from
> $50 - $100 for a good quality LED fixture vs standard fluorescent T8
> lighting to get the same results. Unless you are keeping something such as
> special SPS corals in a saltwater situation, I don't see that as being worth the
> extra expense, thus my recommendation to not bother with the LED for this
> tank. It simply wouldn't be worth it. T8 doesn't give off excessive amounts
> of heat such as the incandescent or CF bulbs would, and should be plenty to
> fix your problem without raiding your pocketbook.
>
> Dawn
>
> --- In _AquaticLife@yahoogroups.com_ (mailto:AquaticLife@yahoogroups.com) ,
> "rachell7" <rachell7@> wrote:
> >
> > What do you use for lighting in your tank? My 10 gallon still has the
> original hood with incandescent light blubs which need replacing far more
> often then I like and do contribute to heating my tank, great in the winter
> but not so great in the summer when it's 112 outside! But with summer here,
> to keep the heat down, I borrowed the hood from a friend's empty 20 gallon
> tank that has florescent lights and I like it. So now I am thinking about
> changing to either the florescent or LED. Give me your opinion please! I
> believe Dawn you said you use the LEDs when I commented on your photos?
> > Rachell
> >
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
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