20w screw-in cf?

[Mettle]

I don't know if they're actually referred to as cf bulbs or not - but they're the self-ballasted screw in ones that people tend to use in the old incandescent hoods.

I was at Walmart today buying some lights for my 15 gal hospital tank (those spiral screw-ins), some other bulbs for the light in my room, and bulbs for my beardie that are actually the wrong wattage.  :roll:  While there I saw these neat 20w screw in energy saver bulbs that are like the spirals. It's 20w and a lumens rating of 1200.

Is this any good?

The only problem is the base is quite large, but that's fixable... I was just wondering... I didn't end up using it because of the base size and will be returning it tomorrow (along with replacing the ones for my bearded dragon) but it's nice to know it's out there.

I was able to grow vals in my 10 gallon VERY well with two 13w screw-in spirals and peat plates. I was trimming back a good two to four inches per week. So this 20w one would be amazing, heh.

[darkdep]

They are called Compact Fluorescents, yes.  Keep in mind that screw in CF's aren't as efficient as straight fluorescents, but ignoring that a 20w CF is supposed to be equivilent to a 90w incandescent for light output.

Home Depot also has 23w ones that are equiv. to 100w bulbs.  I use a bunch of these in my house.  I haven't put one on a tank yet, but it would probably be hella bright

[squeeker]

I actually found some straight screw-in 20W CF bulbs on MOPS that are 50/50 actinic...

Hel-lo, salt water!

[DARKPHREAK]

Nope they wont work in Saltwater.

[squeeker]

Why is that exactly?

[DARKPHREAK]

Not enough PAR. They might add some colour to the water though and maybe enough light to grow macro algea.

[squeeker]

What exactly does PAR mean?

Do you mean it's not enough actinic spectrum?

The plan was to put 4 of these over a 10 gallon.  You're saying that isn't enough light for some reason?  Please explain.

[DARKPHREAK]

I'll respond abit later if its ok... Im in a game of Americas Army right now and Im getting shot at  

[squeeker]

LOL, yah, that's fine.

If you'd rather PM me, that's cool too... don't wanna hijack Mettle's thread TOO much!

[luvfishies]

1200 Lumens is a little low, the light will "show" yellow.

If you can find the Philips Daylight CF bulbs, grab them!

I've used many of these pigtail CF bulbs, and my plants do love them.

[DARKPHREAK]

PAR also known as photosynthetic photon flux density (PPFD). I guess it all depends on what you plan to keep in this tank. If its fish only go ahead and use the CF bulbs but if you think that at any point in time you'll want corals its better to buy something that will allow you to do so now.

[Mettle]

The 20w bulb I found isn't curly. It has three Us on it.

[BigDaddy]

PPFD and PAR are seperate values.

PAR stands for photosynthetically active radiation.  Actually PAR is shortened... the true value is PARFD (photosynthetically active radiation flux density).

PAR is measured in Wm-2 while PPFD is measured in umol m-2s-1

[Nelson]

PPFD and PAR are seperate values.

PAR stands for photosynthetically active radiation.  Actually PAR is shortened... the true value is PARFD (photosynthetically active radiation flux density).

PAR is measured in Wm-2 while PPFD is measured in umol m-2s-1

I knew that :shock:

[DARKPHREAK]

I didnt

But I still think the screw in CF bulbs wouldnt work on a salt tank with corals.

[squeeker]

Even if they aren't curly?

Sorry if I'm being a pain Dark... but I still don't quite understand why it wouldn't work.

[darkdep]

I think what he's getting at is the fact that compact fluorescent screw in bulbs are designed as regular light bulbs; that is, throwing light in a fairly spherical direction (which is ideal as their intended purpose is to replace regular light bulbs).  But, they lose a lot of efficiency in our application, where we want most of the light to go straight down.  In other words, the traditional WPG rule doesn't apply to these; 20w of compact fluorescent does NOT even come close to a 20w straight fluorescent tube.

Now, with that being said, IMHO they are visibly quite bright and they grow plants for me.  Perhaps they lose enough efficiency so they won't be enough for corals tho?

[DARKPHREAK]

What he said

Screw in CF's don't provide enough light for corals but they are fine to light a tank with just fish. You might be able to "keep" easy corals, mushrooms and such but they will not thrive. An unhappy coral is something you dont want in your tank, small problems happen fast in a small tank.  IMO of course

[BigDaddy]

I would think its a simple question of intensity.  The intensity you need for salt simply can't be packaged in that small a housing.

As an example, I have two 10 gallon tanks at work.  1 has a 36W linear CF overdriven to 40W.  The other has two 14 watt "corkscrew" bulbs.

Difference in plant growth is night and day.  I treat the 28 w tank like a "high" low light tank and the 40W tank as a "high" medium light tank.

Yes, there is a difference in wattage... but the linear CF is clearly more effecient.

[squeeker]

OK, maybe I don't understand the difference between linear and linear, lol!

The bulbs i am talking about are NOT CURLY... they are in a STRAIGHT line.  Is the difference between one type of linear bulb and another the way it is installed, ie a screw in type is less efficient than the other ones with the pins or whatever?

Here's a link to the bulbs in question:

http://www.mops.ca/cgi-bin/SoftCart.exe/cshop/LICL-54210.html?L+scstore+wyqr0768ff1cc01c+1137481428

Even if they're less effective, wouldn't 4 X 20W over a 10 gallon be sufficient?

If not, that's fine, I am just trying to make sure I understand WHY.

I'm SO sorry if I'm being thick today...