Dear Kent:
A pH of 8.4 is just fine and having zero nitrates is outstanding. As long as your pH is good and you have very little nitrate in the aquarium, you might consider adding a seahare to bolster your cleanup crew. They love to chow down on green hair algae and should make sure work of it, so that might be a good option for you providing you do not have a lot of nice Gracilaria, Ulva sea lettuce, or other attractive macroalgae in your tank. (The seahare won’t discriminate between the undesirable hair algae and the decorative macroalgae.)
You can obtain a seahare from Ocean Rider (seahorse.com) if you would like to give one of these living lawnmowers a try, Kent. Just copy the following URL and paste it in your Web browser, and it will take you to the information regarding seahares:
http://seahorse.com/shop/index.php?main_page=product_info&cPath=17&products_id=65
However, if you’re going to use a seahare as a means of biological control for the hair algae, then I would recommend using some form of chemical filtration media in your aquarium, just in case the seahare becomes startled or feels threatened and releases its purplish ink. Should it do so, the ink is harmless as long as you have chemical filtration in the aquarium that will quickly remove it from the water. Chemi-pure or a good brand of steam-activated activated carbon would work well for this purpose.
Best of luck ridding your seahorse setup of the dreaded hair algae, Kent!
Respectfully,
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
