Water Conditions et al

Nothing much going on, so here's todays water conditions and some photo's.  This weeks water change has just been completed.  I wanted to wait on the water testing until after the change to have a starting point.  I normally do 5% per week (4 gallons), but today I did a 10% change - I forgot to remove the detritus from the power filter and needed some more water.  And since I was in there a second time, why not vacuum the other half of the tank...

Ammonia - .25 ppm
Nitrates - 10 ppm
Phosphates - 0 ppm
Nitrites - 0 ppm
Alkalinity - 300 ppm
pH - 8.4
Specific Gravity - 1.0235
Skim Level - 7/8"

I think it's interesting to watch the history of the water conditions.  It's a textbook study of causality.

While watching the tank feast on ZooPlex, the Brittle gave me a wave.

Not only do the Clowns seem to love ZooPlex, the anemone seems to enjoy it as well.
Here it's folding up a bit, presumably to ingest some ZooPlex that it's caught.

I guess feeding for the anemone allows the Clowns to do a little housekeeping underneath.

WARNING - DRY SCIENTIFIC CONTENT BELOW, SOME OF WHICH IS MORE OR LESS ACCURATE

Let's start at the beginning of the nitrogen cycle:

• Before adding the new inhabitants, skim levels were about where they are now.  Prior to the new inhabitants, I attributed the higher DOC levels to baterial die-off - without fish (only crabs) there was a lot less ammonia to feed the ammonia-consuming bacteria.  Now I think the opposite is happening.  There are inhabitants, they are being fed, and DOC levels have -at least- remained the same (sometimes spiking).  With this amount of feeding and inhabitants, about 1" of skim level is expected to be the new norm.
• Ammonia levels were at zero prior to the inhabitants.  They initially rose to .25 ppm with the addition.  Then the cloudy water day happened and I surmise they peaked at .5 ppm.  Ammonia is still present in the tank at .25 ppm, so it appears as though my tank is going through another cycle (the ammonia-converting bacteria has yet to catch up with the new load)
• Nitrites are the next step in the cycle.  Lately my nitrites have been at zero, meaning I have all the nitrite-converting bacteria that is needed with this load.  With no nitrates in the water, all are being consumed and converted into nitrates.
• Nitrates are next.  I surmise I will always have nitrates until I remove the power filter.  The power filter can easily house the bacteria that converts ammonia to nitrite and nitrite to nitrate, but not so much with the bacteria that converts nitrate to nitrogen gas.  Those bacteria need a oxygen-deprived area to live.  A power filter with constant flow is not an inhabitable environment for those type of bacteria.  However, the nitrate-consuming bacteria that live in the live rock are the one's keeping the nitrates from collecting faster than they already do.  They live next to the nitrite converting bacteria.  Once nitrate is produced, it is handed off to the nitrate converting bacteria.  Nitrate in the water does not have the chance to make it to it's host bacteria since that would take some sort of flow.  Water flow contains oxygenated water, and those bacteria cannot live in oxygenated environments...  See why I want to remove the power filter?  I will still need some sort of particle filtration (aka sump), which is why it's back in the tank now.
• Phosphates are necessary, but only in minute quantities.  I have none in the water (after the water change), which is good.  Like nitrate, that simply means I don't have any "unused" phosphates.  They are still in the tank, just not in the water.  Phosphates are locked up in the live rock and substrate, in the flora, and in the fauna (due to them receiving it via food).  Yesterdays test had .25 ppm of phosphates in the water.  Today I'm back at zero (or very close).  That tells me everything is saturated with the phosphates because it was in yesterdays water.  With more time, it will be interesting to see phosphate in my causality scheme.