too much light?

I have MH 150W
Tank is 120l (~30gal).
Light hangs 25cm above surface of water.
Height of tank is 35cm.
I've put 6kg of live rock, but it looses colors and is getting white,
fastest in the center of tank, where light is strongest. Also algae
doesn't want to grow there, even Derbesia.
I want to have mainly soft corals, is this light too strong for them?
Can i weaken light? maybe some kind of filter? or should i exchange 150W
into 70W?
Marx

Marx, you don't have too much light at all. 150w of light 10" off the water of
a 30g is weak, actually. I've got 165w of PC lighting over my 29g.

Coralline can fade to white but later bounce back. Perhaps your water
parameters are a tad off, so I'd recommend you test pH, Calcium and Alkalinity
to see where those numbers are.

Marc


Marx wrote:

I have MH 150W
Tank is 120l (~30gal).
Light hangs 25cm above surface of water.
Height of tank is 35cm.
I've put 6kg of live rock, but it looses colors and is getting white,
fastest in the center of tank, where light is strongest. Also algae
doesn't want to grow there, even Derbesia.
I want to have mainly soft corals, is this light too strong for them?
Can i weaken light? maybe some kind of filter? or should i exchange 150W
into 70W?
Marx

--
Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
Business Page: http://www.sparklingfloorservice.com
Marine Hobbyist: http://www.melevsreef.com

Marc Levenson wrote:

Marx, you don't have too much light at all. 150w of light 10" off the water of
a 30g is weak, actually. I've got 165w of PC lighting over my 29g.

Coralline can fade to white but later bounce back. Perhaps your water
parameters are a tad off, so I'd recommend you test pH, Calcium and Alkalinity
to see where those numbers are.

PH 8,25
KH 7dKH
Ca 300ppm
Mg 1000ppm

Those numbers are from memory, i'd note them at home, and will correct
if needed.
I'm dosing kalkwasser daily as top-off water.
I'm trying dosing MgSo4 as Mg supplement.
It's rather new tank.
I made DSB based on silica sand, but it caused algae bloom (cyano I
think) so i got it off.
Recently i added superactinic fluorescent Philips TL/03 20W, and bought
coraline sand to put instead of silica.
The last thing i suppose can cause problems is dual-ended MH, which is
known to not have shielding (my lamp have simple glass, not special).
I'm goig to hang today special AquaMedic glass as additional filter to
lower UV.
Marx

Your Calcium level is very low. It should be within the range of natural
sea water which is 400-450ppm. You could stand to raise your KH, too.
Between 8-11dKH is good.

-Todd

"Marx" wrote in message
...
Marc Levenson wrote:

Marx, you don't have too much light at all. 150w of light 10" off the
water of
a 30g is weak, actually. I've got 165w of PC lighting over my 29g.

Coralline can fade to white but later bounce back. Perhaps your water
parameters are a tad off, so I'd recommend you test pH, Calcium and
Alkalinity
to see where those numbers are.

PH 8,25
KH 7dKH
Ca 300ppm
Mg 1000ppm

Those numbers are from memory, i'd note them at home, and will correct
if needed.
I'm dosing kalkwasser daily as top-off water.
I'm trying dosing MgSo4 as Mg supplement.
It's rather new tank.
I made DSB based on silica sand, but it caused algae bloom (cyano I
think) so i got it off.
Recently i added superactinic fluorescent Philips TL/03 20W, and bought
coraline sand to put instead of silica.
The last thing i suppose can cause problems is dual-ended MH, which is
known to not have shielding (my lamp have simple glass, not special).
I'm goig to hang today special AquaMedic glass as additional filter to
lower UV.
Marx

Agreed. When you get your water to NSW levels, you'll probably see the algae
blooms decrease substantially.

Marc


Todd Nicholson wrote:

Your Calcium level is very low. It should be within the range of natural
sea water which is 400-450ppm. You could stand to raise your KH, too.
Between 8-11dKH is good.

-Todd

"Marx" wrote in message
...
Marc Levenson wrote:

Marx, you don't have too much light at all. 150w of light 10" off the
water of
a 30g is weak, actually. I've got 165w of PC lighting over my 29g.

Coralline can fade to white but later bounce back. Perhaps your water
parameters are a tad off, so I'd recommend you test pH, Calcium and
Alkalinity
to see where those numbers are.

PH 8,25
KH 7dKH
Ca 300ppm
Mg 1000ppm

Those numbers are from memory, i'd note them at home, and will correct
if needed.
I'm dosing kalkwasser daily as top-off water.
I'm trying dosing MgSo4 as Mg supplement.
It's rather new tank.
I made DSB based on silica sand, but it caused algae bloom (cyano I
think) so i got it off.
Recently i added superactinic fluorescent Philips TL/03 20W, and bought
coraline sand to put instead of silica.
The last thing i suppose can cause problems is dual-ended MH, which is
known to not have shielding (my lamp have simple glass, not special).
I'm goig to hang today special AquaMedic glass as additional filter to
lower UV.
Marx


--
Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
Business Page: http://www.sparklingfloorservice.com
Marine Hobbyist: http://www.melevsreef.com

Marc Levenson wrote:

Agreed. When you get your water to NSW levels, you'll probably see the algae
blooms decrease substantially.

I checked my notes
PH 8,25
KH 9,6 dKH
Ca 400ppm
Mg 900ppm
I've just recently bought tests, and Ca was low. Dosing kalkwasser
boosted it from 300 to 400.

Algae
1) bloom - mainly on bare bottom and glass - a layer fast growing,
brown, slippery, with bubbles, on bottom it makes a sheets sometimes
flowing around. A snail seems to eat it (from glass).
2) coraline - how long will it take to see any grow after having good
parameters in tank?

It's latest picture from my tank
http://www.kopernik.gliwice.pl/~marx...cie/IMG_3411_1
What's that animal? It constantly "grab" water searching for plankton.
You can see algae there too.
Marx

Ps. Yesterday I mounted filter glass, hope this help

I've added pictures of algae
http://www.kopernik.gliwice.pl/~marx/gallery/glony
Can you please look at it, and say if that's normal?
As of whitening coraline algae - it has normal color while in shadow,
exposing it to direct light cause them to whiten very quickly (2,3-days).
Also some macroalgae getting white in such condition.
M.