Doesn't look like there was ever reasons given why growth is slow in younger tanks so I'll throw my $.02 worth out for discussion:
Many would argue that it takes 6-12 months+ for a reef tank to mature, but I don't know if it will every fully mature in terms of natural ocean reef conditions. It seems that the longer I have rock in a tank, the more stuff comes back to life...my last tank ran over 4 years and I was still finding new stuff.
I would agree that the process slows after 6-12 months for a couple of reasons:
*The rock is fully cycled and the mini spikes quit
*The bacterial filters have become established
*Natural food is established, i.e. pods
*Hubandry is stable...in the beginning it's more sporadic with the new tank's learning curve, i.e. salinity, water change volume, etc.
*There's less "tinkering" with the tank, i.e. hands in tank, moving powerheads, moving rocks, etc.
The reefing community has begun to agree over the last few years that although lighting and feeding are important, the most important factor in growth is stability. Tanks grow great @ 1.023 & 1.0264, 74 deg or 82, T5's or MH...as long as they're stable.
Growth seems to "take off", but I believe it's also partly an illusion. If you have a 1/4" frag that doubles in size, it's still only a 1/2". If you have a 4" frag that doubles, it's much more obvious. As our colonies mature, there's more visible growth as there's more area to grow, especially with multiple branches.
chatyak, you say the tank's been running since August? How long have the sps been in it? For me, growth is minimal for a few weeks (or longer depending on the speciman) as they acclimate, but as soon as they start to encrust they take off.
As other's mentioned, keep taking pics - sometime you don't realize what's happening until you compare pictures.
You also mention that you're dosing? I've had better luck in younger tanks without dosing. If you're doing regular water changes you should have enough elements, CA, Mg, etc., to get good growth. While dosing has its place, which is for heavily stocked tanks that are depleting elements, in my experience they hinder development in lightly stocked tanks.
My best results have been with regular water changes and fish poop.
Try not dosing (anything) for 1-2 weeks and see if things change.
-Eric
