Browning... but only the green monti cap. Why?

[grav]

Okay this is odd. I have a bunch of SPS in 2 different tanks.

One tank is a 3 yr old 150h with 660w of VHO and 192w of PC Kalk reactor big skimmer and fuge. Nitrates run between 0 and 2. Mixed reef with many softies and LPS. 10x flow through sump, 7x in tank. Bulbs are about a year old.

2nd tank is 5 weeks old 180g with maristar 3*250 hqi and 4*39w t5. Randy's 2-part. Nitrates 2-3. 95% SPS tank. about 20x total flow. Bulbs are 6 months old.

Everything and I mean everything in these tanks looks great except the green (now brown) monti cap. I have Milli, Acros, scroll, montis: digi cap and encrusting, clams, softies BTAs and more. In each tank is a green (brown) monti cap right next to a red (red) monti cap that looks great.

I am due to change my RO/DI filters which will be here on Wed, but thinking 2 steps ahead, any thoughts on the cause here?

Thanks in advance

 

[Len]

So the cap was historically green but turned brown recently? This only happens to me when light conditions vary. Actually, I like it back. When my temp was too high, a lot of my SPS browned out too. But that wouldn't account for just one specimen turning brown on you.

 

[grav]

Yep that is it. The weirdest thing is that there are 2 different colonies (not from the same source) in 2 different tanks. The temp point is a good one. I had only been focused on the water quality, but I'm also having a SMALL increase in temp.

 

[Anonymous]

I respectfully dissagree with Len in that color changes are not always caused by lighting. I agree with his comment on temp tho.

Other things that might be an issue.

You could simply be reaching the point at which you are using more trace elements from the water than you are putting back in. Caps use up a lot of magnesium. Perhaps you could get a test at the LFS?

Also, Rand's two part requires that you keep up with the water changes or risk an (potentially) unhealthy buildup of sulfur compounds.

Another thing to look at is the other inhabitants of the system. If you have some larger softies (or more than one species of sarco) in there that are competing for space, you may be getting some collateral 'damage' from the chemical warfare.

HTH