compact bulbs

[mousey]

I have been using 1 aquarium light on my 20 gal tank plus one household compact flurescent for a total of 30 watts. Plaants have been growing like gangbusters for the past 8 months but now are slowing down. My fert routine has not changed.I am not doing anything fancy-- just have an anubias,vals and java ferns, plus a few giant hygro. The hygros are the ones that are really showing they are unhappy.
the Aquarium bulbs are the screw in type that make the tank look pink.
the household bulbs are "daylight' bulbs and were a special brought in at the local "Canadian Tire" store.they were in a pack of soft white bulbs as a sample of a coming product. i have been back to the store several times but they tell me there are no plans to have daylight bulbs again-- at least not for a few years as people like the soft white instead. i have contacted as many light bulb companies( Ge, sylvania, Philips) as i can and they all say they have no plans to market daylight bulbs in canada. The ge bulbs you all talk about here are also not avail. here.
If i use household screw in compact flourescent bulbs of the soft white variety will there be enough of what the plants need to have them grow, do you think??
I can buy more aquarium bulbs but at $29.00 they are a bit too expensive to replace every 6-8 months. I have 3 tanks With spots for 2 bulbs on each.
mouse

[Wasserpest]

I would not use the soft/warm white bulbs. They will make your plants grow, but also algae, and the yellow makes a tank look really ugly, although that's personal preference of course.

I just can't believe you can't buy daylight colored screw-ins in Canada. They are not easy to find, but if you search a little, you might get lucky. I remember posts about Panasonic bulbs, and while grossly overpriced, you might get some "Full spectrum Envirolite" bulbs from a "Hydroponics store" or nursery supply.

Finally, just try and see if the warm white bulbs make you and the plants happy... they are cheap enough.

[malkore]

Unfortunately, running a power compact for 12 hours a day...it's gonna lose it's plant spectrum in 9-12 months. It still looks fine to the human eye, but the phosphors in the bulb are degraded by that point, so the bulb would require a replacement.

[Rex Grigg]

Originally Posted by malkore

Unfortunately, running a power compact for 12 hours a day...it's gonna lose it's plant spectrum in 9-12 months. It still looks fine to the human eye, but the phosphors in the bulb are degraded by that point, so the bulb would require a replacement.

Hmm... not sure if that's really accurate. Tom Barr says he will take all the used PC bulbs you will send him. He basically runs them till they die.

[Rolo]

I agree with Rex. I read that the degradation of the phophors are only critical for reef tanks and do not matter for planted tanks.

[Laith]

That is *very* interesting. Has Tom detailed why etc...?

I ask because currently I'm using NO tubes (T8s) and changing them out every 6 months as I'd always heard that after this time they declined drastically in being beneficial for plants...

Is this a myth?

[Rex Grigg]

Tom has tested PC bulbs and as I recall NO bulbs. And he runs them all till they die. It seems that the idea of replacing the bulbs comes from the Reef people. And the spectral shift is very hard on the corals. Also remember that this "wisdom" is several years old at least and was formed back when keeping corals was a new and novel idea and just getting enough light to keep what are now considered "easy" corals alive was hard. So combined with the spectral shift and gradual loss of light it was hard on the corals.

New PC bulbs are much brighter and a bit higher in spectrum than older bulbs. But the loss of both is about 10-20% maximum during the life of the bulb with most of this loss coming in the first few months.

So yeah I would say it's pretty much a myth in the planted tank area that you have to replace the bulbs frequently.

[Wasserpest]

On the famous other hand...

Recently someone suggested that over the lifespan of a bulb, they start to draw more current, up to twice of an original bulb. That was in connection with T5 bulbs, which are/can be run by special ballasts that will switch them off once they reach a certain current, to avoid ballast death.

Is that just a total myth?? Doesn't apply to all fluorescents?

[SCMurphy]

They can't draw more current then is available, a 54 watt ballast will supply 54 watts (the wattage of a 48 inch t-5 is 54 watts, if anyone wants to know my reference). That is why we go to such lengths to overdrive bulbs, forcing more current though the bulb then would normally be drawn.

It sounds like a myth to me. Is Sam around?

[Wasserpest]

There is something called an End-of-life-circuitry in T5 ballasts, maybe that's what I meant

4' T5 HO bulbs are 54W, the regular 4' T5's are 28W or 38W, just fyi...