acropora help


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I recently set up a new 10 gallon reef tank. I have several clams, Pocillipora, 2 acros and various other soft corals. I have a 70 watt halide lighting system. And an eheim to filter. The problem is that everything in my tank is loving it except for my acros. They opened when i first put them in there but now they only partially open when the lunar lights are on. There is a powerhead circulating water somewhat briskly so i cant seem to figure out what is going on.All my other corals and fish love the light and the tank so should i be worried or give them more time?

With it being such a small tank you may be running into issues with the soft corals excreeting chemicals affecting the SPS.
Another thing to keep an eye on is your Ca and (specifically) Alk. You tend to get better polyp extension with proper water chemistry (without sounding too obvious here).
Are you running carbon? IMO, if you plan on keeping SPS with softies you must run carbon 24/7.
I agree with Tony. If you have soft corals and SPS in a 10 gallon tank chances are chemical warfare is going on. Ditto on running the carbon.
Some SPS extend much less in the daylight hours. If they have suitable light, they will be deriving much of their energy from phtosynthesis during the day, and will extend their polyps at night to capture planktonic food. It does not necessarily mean they are unhealthy. Do you see any other symptoms? Definitely rule out other issues as Tony mentioned, also. Do you have a strong current blowing right at the acro?
so you say many clams, how many is many in a 10? I had two and I ran thu calc and alk pretty fast, make sure those levels are stable as well as magnesium, that plays a role too. Just make sure you have your acros up high in the tank and have lots of flow hitting them :)
Not to burst your bubble Scott, but I agree with what everyone else has said. Try running the carbon, if that doesn't help, then you have an excuse to upgrade! :)

May I ask - what's your experience level? Those types of animals in a 10g is difficult at best...

Assuming that phosphates, nitrites, and nitrates all read 0, the tank is healthy and stable (at least 10 months and coraline larger than dime size on back glass), and no algae problems, then check alkalinity / hardness. Try to get it above 10 dKH (very slowly, as it will directly affect your pH). I shoot for a balanced system of 425ppm calcium and 12dKH myself.
Are you using an Eheim canister filter? Are you running a skimmer? If you're not skimming and running a canister filter, I think you might find a high nitrate level.