To provide a little background on my set up. I have some history with these guys as well as a husbandry with a lot of other inverts, fish, and exotics - so it was kind of nice having something for my office I didn't need to worry about when I'm working from home part of the time.
I've had my opae ula shrimp and snails from petshrimp.com for about a month now. I got 25 shrimp and 10 snails as well as the source macroalgae, algae ball, and some black lava rocks. I have them set up in a cycled 5g bowl tank with some very carefully processed decorations (I do thorough rinses, overnight soaks in distilled water, and test soaked water for any concerning quality levels). They're on crushed aragonite that was well rinsed (until water runs clear) then rinsed again with distilled water. The water is reef salt + distilled with a salinity of about 1.011. They're on a cycled light but there's no natural light in the room.
So far things seem to be going really well. It's hard to count 25 shrimp in the set up due to the bowl magnification but I've seen a few molts and most of them seem happy, healthy, and red. (Also I honestly don't know if I would see a dead shrimp or if it would just disappear, more or less). I plan to hopefully add some more shrimp since 5g could likely handle a little more.
Now to my actual questions! Below I attached an image of what seems to be happening to my macroalgae. I think it may be growing some kind of red/brown algae on it. Those areas seem a little thinner (they're also the closest to the light) and like some of the filaments are browning. Overall the macroalgae is pretty dark green, which I'd expect to be good. Is this brown algae something to be concerned about harming the macroalgae or the tank in general? The shrimp don't seem to be trying to eat it.
My second question is what technique do you use to top off your tanks without causing stress to the shrimp? I top off usually every two weeks with distilled water to account for any evaporation but every time I do all the shrimp go pale and start frantically swimming as they seem rather stressed out by the whole ordeal. I add it very slowly with bowl I partially submerge with the water. I want to reduce causing them any stress if I can!
Additional pictures of my bowl, for reference.
