This little Acan colony was doing very well. Always puffy & expanding well. The past couple of days it has shrunk down. Does this look bad enough to worry?
40 gallon system: 36G bow with ~4G CPR AquaFuge w/ skimmer
Nitrates: 0 - 20
pH: 7.77 (more on this later)
Nitrates have been as high as 20, but after a 10G water change yesterday and a thorough cleaning of the Fluval it's staying at 0 today.
Acan shrank up before the water change though.
Suspects I can list:
- Change to 250W MH Pendant recently, though I've been very gradual with the acclimation. (Still only up to 5 hours/day with diffuser & about 10" off the water)
- Recent trouble with pH swings. pH has never been comfortably above 8.0, but now with a closed up house it dips down to 7.6 at night. Once as low as 7.5. This is measured with a calibrated pH probe & Apex Lite.
- Green Hydnophora added to tank about 6" below the Acan last Saturday.
The Acan is about 6" deep, so relatively high. But was fine with the extra light until a couple of days ago.
I have no way to improve air quality in the house, it's a rental so I'm not punching a hole in the wall for the skimmer air.
(THRIVE) helps a bit of course, but lasts < 24hrs and I don't want to push dKH
too high. So I'm a little stuck about what to do for pH.
How do Hydnophora hurt other corals? I've heard they are very aggressive, but I don't know how they do it!
Acan used to look like this:
Proximity to Hydnophora now:
Another Acan lower in the tank looks fine: