HELP! Giesemann bulb makes water yellow!

campaign000 · Jun 30, 2018

I updated one of my tanks to Giesemann 250w 12500k MH yesterday. But the water looks ugly yellow comparing with the left tank using Giesemann 15000k & blue T5s.
Is it normal and good for clams?
Thanks guys!

Shigshwa · Jul 1, 2018

Well. The blue T5s are probably why the light looks blue. MHs on their own are gonna take on a more pure white color. You should be alright, 12k is still pretty spectrally sound for corals and clams. Might wanna look into a higher kelvin bulb if you don't like the yellow color.

Venator · Jul 1, 2018

Yeah, clams are pretty good when it comes to light—provided they get enough light. I personally enjoy a much higher kelvin (and so did my clams—maxima and derasa). Good luck!

campaign000 · Jul 1, 2018

Shigshwa said:
Well. The blue T5s are probably why the light looks blue. MHs on their own are gonna take on a more pure white color. You should be alright, 12k is still pretty spectrally sound for corals and clams. Might wanna look into a higher kelvin bulb if you don't like the yellow color.

I like 15k T5 the most but it's said that 10k MH is better for clams. I just didn't expect it's so yellow, so I wonder there is anyone using the Giesemann MH bulb as well.

campaign000 · Jul 1, 2018

Venator said:
Yeah, clams are pretty good when it comes to light—provided they get enough light. I personally enjoy a much higher kelvin (and so did my clams—maxima and derasa). Good luck!

Thanks man!

Venator · Jul 1, 2018

campaign000 said:
Thanks man!

It’s also somewhat risky to judge light and individual spectrum intensity through just looking at the stuff. If you are seeing signs of too much/too little intensity, I would rent a PAR meter.
The blue->UV (below 500 nm) has the shortest wavelengths, thereby having the highest frequencies and most energy of the visible spectrum. Conversely, the GYR spectrums (in that order, around yellow) have the longest wavelengths, and lowest energy, making the photons slower and more visible to the human eye. This is why white light overpowers blue light, but also why corals have a higher propensity to the 460-470 nm spectrum and why some may melt or bleach at more intense lower kelvin spectrums. (I probably botched this, hopefully I made it easier to understand with this layman’s explanation. To be fair, I’m not even an adult though, so...;))
Well, good luck either way!