First of all...Welcome to AA.com! I think you'll find this site to be a great resource.
My first piece of advice to you is to get a copy of "The Concientious Marine Aquarist" by Robert Fenner. This book is an excellent source of info for newbies and experts alike.
The brown algae you described sounds like diatoms. They are a normal part of getting a SW
tank going and will usually go away on their own assuming there are not excessive nutrients in the water. It could be a type of hair algae due to the phosphate, but this is usually green in color.
I'm not sure why you're feeding phytoplankton. This is usually used when you have filter feeders in the tank and it doesn't sound like you have any. Most of the time, filter feeding animals will do fine on what's already in the water from feeding the fish and the waste generated by the fish.
I would not rely on brine shrimp as a primary food source. Your fish need nutrients that are not supplied with brine shrimp. And, unless the brine has been enhanced with other nutrients, it has very little nutritional value. I would suggest getting some marine flakes and a variety of frozen foods. You can make your own frozen food from seafood that is available at most any supermarket. Do a search here on "blender mush" for the recipe.
As far as the phosphate problem is concerned, what kind of water are you using? If you're using tap water, that is probably the source of the problem. You really need to use RO
water or distilled water. There are all sorts of impurities in tap water that can cause you headaches with a SW
tank. Another thing you will have to address is nutrient export. Most of us use a protein skimmer and water changes to achieve this. If you don't have a skimmer, I would recommend an Aqua C Remora with a surface skimmer. A less expensive option, although less effective, would be a Prizm with the surface skimmer. Don't bother with a Seaclone...they just don't work all that well.
The algae you want to cultivate is called coraline algae. You can tell it from the others because the coraline is a calcerous algae. It's hard and usually starts out as small round dots on the rock and tank walls. Purple is probably the most common color, but I've seen pink, green, and orange. You can remove it from the front glass with a razor blade. Any type of algae that is hairy, stringy, or slimy is bad news and you'll want to get rid of it. The keys to coraline growth are adequate light, calcium, and keeping your alkalinity levels within needed parameters. To do this, you'll need test kits for calcium and alk
. You'll also need kits for pH and nitrate. I'm guessing your tank has cycled? If not, or if there is any question there, you'll want to have ammonia and nitrite kits on hand as well.
About the goby...many SW
fish will fade out a bit when the lights are off. I wouldn't worry about him as long as water parameters are within specs.
Your NO fluorescent won't be enough for corals. You really need at least two bulbs for coraline algae growth. Upgrading to a couple of 65w PC
fluorescents would allow you to keep the corals that don't have very high light needs. Most of the soft corals, mushrooms, ricordia, zoanthids, ect... Probably wouldn't be enough for SPS
I would like to hear more about your tank setup. How much rock do you have? What kind of filtration are you using? What are your water parameters? pH, alk
, calcium, nitrate, salinity...and what are you using to measure these parameters? How deep is your sandbed and what kind of sand is it? What kind of light bulb do you have in the hood? And finally, what is your end goal for this tank? Reef tank with corals?
You might want to check out the SW
articles on this site as well. You'll see, on the home page, a link entitled "articles". Lots of interesting info there. BTW
, the regular crab you have sounds like a mithrax or emerald crab...usually good tank inhabitants.