A couple of questions?

Well, the red spots appear to be cyanobacteria, which is loosely grouped in with algae. You didn't post any water parameters, but since we see the cyanobacteria we know that there are enough nutrients in the system for them to flourish. You are using natural seawater; have you checked it for nitrates and especially phosphates?

I noticed that you have a canister filter on your system. The cyanobacteria can be dealt with in a number of different ways, but since you already have a way to employ a phosphate absorbing media, why not load up the canister filter with something like PhosGuard, PhosBan, Phosphate Sponge, or Polyfilters? If you are keeping up with your regular water changes and the phosphate levels are reasonably low to begin with, the unwanted algae (and cyanobacteria) should start to disappear. A good assortment of algae eating crabs and snails will also help, as will the addition of herbivorous fish and a vigorous flow of water in the aquarium.

The second picture is that of a Glass Anemone, or Aiptasia. You will want to get rid of the ones you see as soon as possible. One way to do this is to fill a small syringe with kalkwasser and inject the anemone. Some folks give them a shot of boiling water. I'm sure others will post their own methods of dealing with them. They are an unwanted nuisance and they can multiply quickly. The Copperband Butterfly is a fish that will prey on Glass Anemones, but they can be hard to keep in captivity and are best left to aquarists with a lot of experience.

The news is better for the guy in the third picture; it's an Emerald or Mithrax crab. They are herbivorous and are beneficial in the control of hair and bubble algae such as Valonia.

Your book will no doubt cover these topics in much greater detail. Good luck to you and your aquarium!

Paul

yea id add a phosphate removing media to the canister filter and then get rid of that apitasa.

ur phosphates are 8.2?! thats not good they hould be over .05 really...u sure that isnt ur ph? also phosguard is a terrable product and actually leaches a significat ammount of aluminum into the water i would use it. rhophos, phospure, and other "expencive" products are better to use.

ok good..lol no the ph should be in the range of 8.0-8.4 so ur good.

Based on the pictures you have provided I think you are becoming overly concerned about a very small problem. Remember, this is supposed to be fun!

PhosBan is a good product. I have read Germanman's objection to PhosGuard in previous posts. His personal observations are worthwhile to consider. Use one of the other products instead.

The next time you do a water change, siphon the algae off of the rocks. It has consumed ("fixed") nitrogenous waste from the water column and siphoning it out will export it from your system.

One of the more amusing aspects of our hobby is that the water from a system completely overgrown with algae can test extremely low in nitrates and phosphates. Algae can strip these nutrients from the water very quickly. There's plenty of phosphate and nitrogen in the system; it's just not dissolved in the water column where you can test for it.

My assumption throughout this discussion is that you are not using salt mixed with straight tap water or raw seawater . (Right?) You wouldn't want to inadvertently add the nutrients that you are trying to keep out.

For now, get your hands on some type of phosphate removal media and put it in your canister filter. Siphon away algae when you do water changes. And most of all, don't forget to enjoy your aquarium.

Paul

johansonp said:

Based on the pictures you have provided I think you are becoming overly concerned about a very small problem. Remember, this is supposed to be fun!

PhosBan is a good product. I have read Germanman's objection to PhosGuard in previous posts. His personal observations are worthwhile to consider. Use one of the other products instead.

The next time you do a water change, siphon the algae off of the rocks. It has consumed ("fixed") nitrogenous waste from the water column and siphoning it out will export it from your system.

One of the more amusing aspects of our hobby is that the water from a system completely overgrown with algae can test extremely low in nitrates and phosphates. Algae can strip these nutrients from the water very quickly. There's plenty of phosphate and nitrogen in the system; it's just not dissolved in the water column where you can test for it.

My assumption throughout this discussion is that you are not using salt mixed with straight tap water or raw seawater . (Right?) You wouldn't want to inadvertently add the nutrients that you are trying to keep out.

For now, get your hands on some type of phosphate removal media and put it in your canister filter. Siphon away algae when you do water changes. And most of all, don't forget to enjoy your aquarium.

Paul

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nice very well said i completely agree i would have come up with something like that if i wasnt at school earlier.