Sorry to go off topic here but Landshark, where did you get the T5HO 18"? I've been looking for them and haven't found those short ones anywhere.

Do you have a photo of your tank that you could post? What are your water parameters? Ammonia, nitrite, nitrate, pH, temperature, salinity, and phosphate. Calcium, alkalinity, and magnesium if you have kits for those. Those last 3 can be bigger contributors than many people are aware.

When you say bigger contributors...what do you mean. I'm getting some hair algae for the very first time since I started my tank over two years ago and my Calcium and Alk are very high. Mag is normal.

A lot of people who are having hair algae issues have low calcium, alkalinity, and magnesium. The latter two being more significant. Saying your cal and alk are "high", and your mg is "normal" doesn't say anything...what are they actually at?

A prime example...I noticed the tiniest of shoots of hair algae in my tank, so I tested my parameters which I haven't done in awhile. Hehe...oops. My magnesium was down around 1250 ppm, my alkalinity was just over 7 dKH, and my calcium was down at 370. I brought my mg back up to 1400, and my alk back to 9-10, and my calcium to 430, and poof hair algae gone. I didn't do anything else to the tank. My tank hasn't had hair algae since it was first cycling over a year ago, so I knew something was up.

"Everyone" knows that nitrates and phosphates are significant contributors to algaes in general, but keeping all your parameters in check is important even in FO tanks. :)

Well, just tested last night.

Cal at 500
alk at 12
Mg at 1450

Salfert and hagen test kits used on every test in order to double check.

I'll PM you since this is off topic from the OP's original question. :)

Thanks for all the great advice! Checked calcium 480, KH 9, But I don't have a test kit for Magnesium. PH 8.3, nitrate 5, nitrite 0, ammonia 0 ,phosphate 0Spec. gravity 1.024-025 . I'll check on algaebase.org exactly what this stuff is. I havn't any access to sea hares or urchins, and not excited about purchasing said critters. Hmm. Rock theory possible, as I just moved some rocks around in my tank that were partially buried in substrate.( about three weeks ago).Wouldn't testing pick up leeching live rock? Sorry, I'm unaware of what a phosban reactor even does. STEVE

A phosban reactor is a canister in which you fill it with GFO (granulated ferric oxide) like Phosban, and it sucks up phosphates. It works reasonably well in the battle against GHA/bryopsis.

You can always just wait it out, manual purning, regular water changes, and turning the rocks helps too. Although this can take awhile.