Zoa/Paly Stems

[40gal]

I just found this thread, which I plan to read in much more detail. What caused me to stumble across it is that I noticed something strange with my zoas in my tank today.

45G cube, lighting is a 110w MaxSpect LED setup (several years old)

One of the first things I put in my tank was a small 2-polyp zoa frag (Jan '14). Put it low in the tank, as I didn't want it to get too much light. Within the first month or so, I had a third polyp. I also added some palys (Feb '14) to the tank, on the opposite side about halfway up. Had 10 polyps, and within a few months they have doubled.

What's weird is the palys have extremely long stalks, and have ever since putting them in the tank. They are multiplying, so I'm thinking they are happy. The original zoas have not grown or multiplied in over 6 months. What is strange is that I moved the zoas up a little in the tank to just over halfway up. It looks like they are stretching for the light, just as the palys do (not near the same amount though). They never stretched like that when they were lower in the tank.

Is something off that I'm seeing this behavior?

 

[40gal]

Here are a couple pictures

 

[40gal]

Excuse the mess, I'm battling an algae problem right now. I caught my tank in the middle of a feed cycle, which is why the water level is so low. The small zoa colony was down near the montipora frag seen in the pictures above since I purchased it.

 

[40gal]

No ideas?

 

[swift_scorpion]

If they are growing they are happy I believe stalk length would be related to genetics primarily and then both light and flow

 

[40gal]

I'm just confused because my zoas that are not growing seem to have stretched stalks after moving them higher in the tank. It would make since had I moved them lower. They seem healthy and all, just not growing at all in the last 10 months or so. Trying to figure out how to get them to thrive.

 

[dentdominator]

I would start with the light set up and replace the bulbs. The bulbs loose spectrum after so much usage. Looks like the zoas are starving for light, that's why they are extending themselves.

 

[40gal]

I would start with the light set up and replace the bulbs. The bulbs loose spectrum after so much usage. Looks like the zoas are starving for light, that's why they are extending themselves.

So that makes sense, except that I'm using LEDs so although I don't know exactly how many hours of use these have, they are proven to last considerably longer than a traditional bulb would.

Also, why would moving them up cause them to stretch? It would make sense if I moved them down and saw more extension. This is the part that doesn't make sense to me.

I'm considering a DIY upgrade to my lighting anyway, so maybe this alone will increase the growth rate. I'm just trying to makes sense of the situation before a knee jerk reaction to resolve something that may not be a problem.