Need Lighting Help / Suggestions

[DiverDude]

I have a 24" Tek light on my 35 gal tank. This is a 4-bulb T5 setup. I've had algae problems pretty much from day one on this tank (tank came with a HA problem from the previous owner). I thought I had it under control a few months in and the tank looked good but while it's not rampant, I'm not winning the war either.

One thing I tried was removing some of the LR I had in the tank in an effort to improve flow. Some of that rock I put into the HOB sump I built.

Now I notice that the rock in the sump is algae free while I still have HA and a few other forms in the display. I also have some kind of algae growing on my korailia's -but pretty much only on the top of the pumps (towards the light). The algae on the koralia's is new in the last few months and is getting worse. I'm thinking I've got a lighting issue.

Ok, so the bulbs I have now were put into service April 7th of last year -so they're ~9 months old. I have:

2 Super actinics
1 Geissmann Midday (6000k)
1 Aquasun (which is supposed to be 12000k but this isn't marked on the bulb)

Theory: I have a bad mix of spectra here (too red) and/or the sprectrum has shifted recently (towards red) or both.

I'm thinking of replacing the bulbs (even though it's a bit early) and need opinions on what mix I should go with. I'm thinking along the lines of 2 actinics and 2 10,000k....

Thoughts ?

[DiverDude]

Update on this....

Did some research and according to the manufacturer of the bulbs, their "useful" lifespan is 4500 hours or a little less than DOUBLE the hours they have on them now. So do they wildly exaggerate these specs or what ?

Also, the Aquasun seems to be spec'd at 10,000K, not 12,000k as I had in my notes.

[daniella3d]

I would replace the 6000k by a 14k next generation or something similar.

That 6000k is definitly for plants, not for coral and will probably help your algae grow fast.

Also check your nitrates and phosphates. Some phosphates remover might help.

[Slick Fork]

I don't really buy into the theory that lights "Cause" algae problems. Algae issues are caused by excess nutrients, if you don't get the nutrients under control you can change lights all day long and it won't make a difference, you'll still get algae.

[DiverDude]

I agree. There *have* to be excess nutrients in the water for the lights to do anything. I've been chasing that dog (unsuccessfully). I do WEEKLY ~20% water changes, all my parameters are bang-on and I have a light bio-load and I feed lightly so I don't know what else to do.

I may be chasing ghosts here but I've seen a few tidbits of evidence that indicate to me that my lighting is not helping the situation.

Phosban may well help but the damned stuff is expensive and I don't have a very elegant way of running a reactor with this setup. Besides, phosban is just masking the issue of excess phosphates anyhow. I'd prefer to get to the root cause.