Alkalinity dropping for no good reason

[iron_mike_gt]

I started a new 180 gallon tank several days ago replacing my old 220. Reader's digest version - there is very little alive in there:

4 mushroom heads - each one the size of my thumbnail
1 flower pot anemone - the size of my pinky finger nail.

I reconnected my trident and let it run a combined test each day just to keep it from sitting idle for multiple months. My Alkalinity has been dropping each day - most recently a .22 drop in the last 24 hours. I find this super surprising given the virtually zero livestock in there and thought I'd post here to see if anyone has experienced this before. Again, easily 180 gallons total water volume (rock/sand offset by a large sump/fuge) and 5 super tiny animals in there. That drop in 180 gallons of water is what is shocking to me.

Thoughts?

 

[Timfish]

Reef systems are pretty complex and there's lots of stuff going on that we can't test for or quantify. One possible issue may actually have to do with your house and the ambient CO2 level. I have a client that spends several months at a time out of the country and I always have low alkalinity issues when they're gone.

 

[Randy Holmes-Farley Verified Community Expert]

Conversion of ammonia to nitrate depletes alk,as will precipitation of calcium carbonate, both of which happen in new systems.