Saltwater Tank Questions

[Sea Dragon]

I have a fully cycled saltwater tank and want to start adding critters. I have (at least) 3 questions:
1. I used Galveston Bay water and it is nice and clear running 7,500 ppm salt, but I keep getting brown fungus or something adhereing to the tank walls and shells in the tank. Any idea of what this is and how to minimize or get rid of it?
2. I am using a cartride filter and fabric bio filter. Will this be adequate in a 5 gal SW tank?
3. I want to add (at first) baby crabs, baby stingrays, and baby shrimp that I can get out of the surf. I figure the crabs will eat almost anything, but what should I feed baby stingrays and shrimp?

Any help would be appreciaited.
Thanks, Tony

 

[djones169]

He brown is diatom alfae. Clears up by itself in a fully cycled tank that doesnt have too much nutrients in the water.

 

[Sarcothelia]

Did you say what to feed baby stingrays? The vast majority of those get much too long, wide for a fish tank, more suitable for a saltwater pond of sorts. Diatoms go away as nitrates etc. are reduced, PWC and some activated carbon will get rid of them in time in a cycled tank.

People feed rotifers to tiny shrimp for sure. Just look them up on liveaquaria or whatnot.

 

[Sea Dragon]

Well, according to my tests the tank is cycled. Regarding stingrays, we catch them at 1/2 inch or less and I plan to release them back to the Gulf once they get bigger. In fact, I plan to release them all back. I really want seahorses, but as I am a newbie I thought I would start with free things before I invest in seahorses. But, of course, I don't want to kill anything.

 

[Sarcothelia]

They would probably eat rotifers, DTs oyster eggs, small krill, zooplankton.

 

[Sea Dragon]

Thanks y'all!