About lights and snails

[bossteck]

Was reading some articles from the site below:
http://www.drhelm.com/aquarium/lighting.html
http://www.drhelm.com/aquarium/snails.html
need some clarifications:

1. About lights: according to the article on lights, i quote:
"Cool White and Warm White
These are the most commonly used and the least expensive. Ok for fish only tanks. Remember, plants require red and blue. These peak in the green spectrum.
Daylight
Closer to a natural color and would be better for plants and still inexpensive."

I remember reading elsewhere, that warm white tends towards to red while cool white tends towards the blue end of the light spectrum. How come they are less suitable for planted tank as compared to daylight?

2. About snails. I quote:
"Snail eating fish - The first and best suggestion in my opinion is the Introduction of snail eating fish. Many of the Loaches are reported to help control the snail population...... The Upsidedown Catfish (Synodontis multipunctatus) also eats snails, again can become 10 inches (25 cm.) in length. Puffers (Tetraodon species)....."

Do upsidedown cats really feed on snails? Haven't seen one in action before.

Thanks for any replies

[Aeon]

Read an article on Vectrapoint before, ADA designers like to use Full-spectrum lights... maybe some of the spectrums for plants and the rest for displaying the fish's best colors.

[vinz]

Cool white tend to blue... and has less red.
Warm white tend to red... and has less blue.

Daylight... closer to "natural" or "white" light and more natural looking to the human eye. They render the colours of the plants and fishes more accurately (based on human perception). Daylight are more likely to be full spectrum... hence makes everyone happy.

[bossteck]

Thanks for the reply.

So, suppose i am using 4 tubes. Is it more advisable to get 2 cool white and 2 warm white, or 4 daylight?

[vinz]

4 Daylights are sufficient.

[bossteck]

Hi Vinz (and others),

Sorry for not being clear, perhaps you misunderstood me. Anyway, I have already bought the tubes and too early to change them (not yet time to replace)

For the sake of discussion. In general, is having a mixture of warm/cool white light tubes and no daylight more effective/suitable for planted tanks than having daylight tubes.

Regards

[bclee]

Colour temperature of warm white lights is around 3000K (towards reddish). Cool white is about 4000-5000K(in between). Daylight is about 6000K-6500K(more blue). Actually daylight tubes appear more blue than cool white tubes.

I find plants will grow under any type of FL. The only difference is probably the response of plants to the light colour. Under different light condition plants may develop different internode length, different leaf size and petiole length.

BC

[bossteck]

I beg to differ... from what I read, and what I see... cool white appears to be more blue then daylight. I remember seeing the 3 bulbs (not FL tubes but those energy saving power compact bulbs) being placed side by side at Giant in parkway parade, they demo the lights by putting them up in the wall socket side by side and switching them on, so that you get an idea of what exactly each one look like. From what I saw, it appears that cool white is more blue.

What about the issue of upside down cat eating snails.. anyone seen this before?

Regards

[bclee]

Human eyes perception is inaccurate. To me, daylight tube is bluer, maybe to you it isn't. The fact base on colour temperature rating, daylight tubes contain more of the blue spectrum.

Colour temperature rating is the best reference to use for decide how much blue or red spectrum a light has. Lower temperature refers to more red component while higher temperature tends to be more bluish.

You can refer to these Osram brouchures:
Light can be white, white, white or white
OSRAM Lumilux

BC