Why do zoos grow long stocks?

[marcingo]

Hi. It seems that everytime I add zoos to my tank after a couple weeks to a month they begin to develop long stalks. Anyone know why zoos develop long stalks? Is my flow too gentle? I used to think maybe Im just getting palys all the time or maybe they arent fully developed and when they develop they grow long stalks. This however cant be the case since I put a fully developed rock with lots of zoos on it from a friends tank. When I got it the zoos were all close to the rock almost no stock. However now a month later they have all grown longer stalks. All my zoos look healthy but they are all growing long stalks and big heads. Anyone know why? I would think I have adequate lighting since I am running a 150 watt HQI DE MH on an 19 inch tank. It is 20k temperature though.

Another thing is my mushrooms are growing abnormally huge as well. Could this be related to the zoo issue?

I have LPS in the tank that is growing very nicely too.

Thanks for your input.