Too much light causing algae

I have a odyssea ho fixture with two 80 watt 10k bulbs and two 80 watt actinic bulbs. The tank is 100 gallons and i was having lots of algae problems. I removed one of the actinic and one of the 10k bulbs and the algae problem has gone away. That leaves me with 160 watts for my my 100 gallon. Is that still enough to support corals. I run the 10k 6 hours a day and the actinic 12 hours a day.

 

How old were the bulbs? I would keep the actinics on for 10 hours, an hour before and an hour after the 10,000K's, and the 10,000K's on for 8 hours. Do you have any corals?

 

You should be able to keep LPS and softies. SPS will need to be at the top of your rocks and under the reflector.

 

The bulbs are about 11 months old and ive read the bulbs that come with the oddysea fixture are crap. I plan on replacing the bulbs soon. Right now i have polyps, bubble tip anenome, colt coral, and a leather leaf coral. They seem to be doing fine and i plan on getting more coral.

 

I think the bulbs that come with most T5 fixtures are crap. Do you plan on getting SPS? My favorite are the ATI bulbs, look at different color combos. Note that you probably shouldn't go and replace all the bulbs at once. I would replace one bulb per week to stay on the safe side.

You should also note that it is not the light causing the algae per se. Yes old T5 bulbs support algae growth better than when they are new. However, the actual cause of the algae growth is the excess nutrients in your tank (i.e. nitrate, phosphate). Changing your lighting may help, but you may want to consider additional methods to remove these substances from your aquarium.

 

I do plan on getting sps and I recently got a TDS meter and noticed the water coming from my ro/di filter was around 80 TDS. Time to get new filters. I will change a bulb once a week.

 

These things should help. Other things that will help are a good skimmer, adding a refugium with LR and macroalgae like chaeto, and adding a GFO or Phosban reactor. You may also want to manually remove the algae that is currently in your tank, as this will speed the process of eliminating it. Sorry if you already knew these things, just trying to help

 

There's a lot of hype on lighting. I have 40 watts on my 20 gallon tank, and my sps are growing great!

 

Change to ATI bulbs and get your TDS in order...should be fine...I had 6 T5s on my 90 and was constantly cleaning glass and PHs...went to LED and life is great ! best change ever ! ...but in your case, good lights are important..try a combo of purple plus and the blue...as well as the white...they look great....(but even good bulbs need to changed annually)..jmo

 

Your tank is a lot shallower than most tanks though. That makes a good difference in required lighting. Though some people probably do go overkill with it.