Alk and Xenia, my observations

[mark]

Well I'm sure that Xenia doesn't like high alk. Had posted my thoughts before but now with some numbers and the Xenia coming back, I'm convinced (at least for my own little world).

Before I got a Ca reactor my tank was overrun with Xenia. Sadly got to the point where I was just flushing it the keep under control. It's hard to describe but it was really crazy mutant.

Since before the reactor, wasn't worried for Alk so wasn't testing for it so all I have for numbers was with I first turned on the CO2 and I had 7.0 dKH. I'll assume (and last one) was that my alk would have been near this level as wasn't supplementing other than the rare time with kalk slurry.

After I got the reactor, the Ca remained low so was pushing the reactor to try to get the numbers up. Ended up finding out for myself wasn't a good idea to drive it hard, as all I was doing was spiking the alk. It was also around here was when I did another big Xenia trim then noticed it wasn't growing or splitting off new colonies.

Eventually realized IO was low out of the pail for Ca, so started supplementing my mix, so turned down the reactor and for more than a year, log looks like the alk was running about 9-10dKH. All this time didn't touch the Xenia once, it really wasn't shrinking but it definitely was not growing.

In February, my alk started to decrease into the 8's but as Ca was staying up didn't adjust anything. March and start of April getting some 7's then started getting busy and hadn't been keeping my chem log up. It was though in about the last month both the wife and I noticed the Xenia was growing, budding and starting to spread out (moving). It's to the point because starting to crowd some acros I might be trimming again. Yesterday (after a month) tested the alk and it's dropped to 6.4 dKH.

So long story but from this cycle, all else equal, I'm concluding if want Xenia growth, low Alk, if trying to control it, high alk.

[Zoaelite]

Very true, I had a period of about a month where I accidentally overdosed my CA like crazy and I watched my Pulsing X just EXPLODE in growth.
Levi

[dstasiuk]

Unfortunately, my Xenia are still spreading like wildfire with alk maintained at 11-12 dkh. I wish they would slow down. My tank runs a Ca reactor, so alk stays consistently quite high, but it has not slowed down the xenia. :cry:

[midgetwaiter]

I think your conclusion might be a bit hasty. Of course it could be that you have a specific species that exhibits this behavior too.

Calfo talks about a few different aspects of Xenia prorogation in Vol 2 of his book. The part that is applicable to this discussion is his observation about pulsing behavior slowing and eventually stopping at pH levels below 8.4. He always maintained his pH at 8.4 or above as a result and was producing thousands of small colonies a month. It would be difficult to imagine that pH being maintained without high alk.

The only thing that is a limiting factor to xenia growth in my experience is low levels of dissolved organics, the cleaner the water the slower it grows. I think this is probably also a factor in your observations because I bet at those higher alk levels you were seeing faster stony coral growth and more importantly higher coraline growth both of which would have an impact on the dissolved organics the xenia needs to fuel it's growth. It was just getting out competed.

Did you noticed a difference in coraline growth with the higher alk levels?