Brown Algae after switching to Metal Halide???

[gotboost15psi]

Hey guys...im starting to notice alot of brown algae growing all over my tank after switching to Metal Halide. Before i had 96 watt power compact with 50/50 bulb. Now i have 175watt 14000k Metal Halide...What could this be? Here are some pics below...

[blue_eyes53813]

How long are you leaving the MH on? Is this a new tank? brown algae is normal in new tanks and it may just have started after you added the mH but not be caused from the lights.

[flricordia]

is the tank temp higher now? Could be causing it. What brand of bulb and is it new?

[CATALYST]

I got crazy algae after I went from pc to halide. I dropped the amount of time they were on per day from 12 hrs to 7...increased flow...fed less. I slowly raised the amount of time the halides are on back up.

[gotboost15psi]

The tank has been running for almost 2 years now and I only had brown algae when i first started. To try and mimic the natural sunlight I leave my lights on for 12 hours a day. Im running a hamilton 14000k bulb and it is new. The tank temp is actually cooler now after switching from Power Compact. I was thinking maybe because the MH has a higher PAR than the PC's and its producting more macro-algae?

[XBwlr]

That's what I would say is happening.
More light is reaching the substrate.

[DaveK]

Keep in mind that plant growth, in this case algae, is going to be limited or controlled by several factors.

The key ones here are available nutrients and light.

Most likely the lower level of light was the limiting factor. Once you increased that, algae could grow, since it had available nutrients.

Algae control is now more a question of controlling nitrates and phosphates, although reducing the light will help.

Notice how you have some very brightly lighted reefs, without algae problems, because nutrients are controlled.

It may be worth a review of your filtration system, including the skimmer, since that can remove a lot of waste products before the system needs to break them down.

[gotboost15psi]

well i have a 20 gallon reef setup...I asked my LPS about using a protien skimmer but he said its not needed with my size setup.... Would i be fine without it or should i invest in one?

[fishnu]

You talk to your large polyp stoney?

[gotboost15psi]

You talk to your large polyp stoney?

LOCAL PET STORE...you been here long enough to know what it means

[fishnu]

Ah LFS!

[vdituri]

I have to second Fishnu.
LPS is Large Polyp Stony coral. lol

[Scouter Steve]

I thought he was stating that his coral wanted dirtier water, as some do!

[blue_eyes53813]

Keep in mind that plant growth, in this case algae, is going to be limited or controlled by several factors.

The key ones here are available nutrients and light.

Most likely the lower level of light was the limiting factor. Once you increased that, algae could grow, since it had available nutrients.

Algae control is now more a question of controlling nitrates and phosphates, although reducing the light will help.

Notice how you have some very brightly lighted reefs, without algae problems, because nutrients are controlled.

It may be worth a review of your filtration system, including the skimmer, since that can remove a lot of waste products before the system needs to break them down.

I agree with Dave, Having the lights on for 12 hours is most likely gonna cause algae problems. My MH are on 7 hours a day to reduce or keep algae down. I do have supplements of VHO and Pcs. All forms of filtration in tanks is important. I think reducing your lighting period will take care of the brown growth.

[JT101]

I have an AquaPod 24 (enclosed hood) with the "standard" wattage PCs that come with this model (Model 7051).

I established the tank early June 2007 and it was fully cycled by the end of July.

I have been doing weekly 50%-70% NSW changes for months with no problems. However, I have very recently (within the last 2 weeks) seen a sudden growth of light brown algae (daitoms?) and sometimes purple algae (cyano?) on the sandbed. This stuff does NOT EVER seem to grow anywhere else, ONLY on the aragonite and NEVER in the shaded areas.

I have not changed my lighting schedule. Water levels are always excellent.

The only thing I can imagine is that there are phosphates in the water. I just read the other day that even absolutely pure natural seawater can have phosphates in it, yet artificial seawater has none.

My corals, shrimp and fish are all flourishing, eating and doing "excellently" but I am worried about the algae.

I have been very carefully scraping it off the sandbed each time I do a WC but it seems to grow back.

Admittedly, it seems to be SLOWLY growing less and less fast as it did when I first saw it but I am very curious as to its source.

Is it time to change my lights? They are not even 6 months old yet.

Any thoughts/advise would be appreciated.

Thanks
John