High pH and low KH.
I’m not going to get in the mix fully yet since I haven’t had a chance to read all the thread but I did want to point out that your pH can be affected (lowered) by CO2 levels which is one of the reasons why your pH is lowest in the mornings. By the end of the day, the plants and algae have been sucking up CO2 (during photosynthesis… and putting out O2) all day long so the pH will usually be higher in the late afternoons. All night long, the ecology of the pond (fish, bacteria, etc.) are putting out lots of CO2, thus the lower pH first thing in the morning.
As far as missing fish, I would suspect predators. You could have raccoons, birds, cats, dogs, turtles, etc., enjoying your smorgasbord of a pond. The smaller the pond, the more likely that predators will go after your fish since they do not have as much room to swim and hide.
You need to establish your source water parameters. I have a recent blog on this but you already mentioned that you haven’t let the water sit for 24-48 hours or more and re-test it. Adding agitation/aeration to the water while it’s sitting for 24-48 hours will give you even more accurate results. You need to do this to get a better idea of how the buffers in your tap water are sustaining once the water is exposed to air, light, etc.
What brand of test kit are you using? Have you checked to see if your reagents are not expired?
Lenny Vasbinder Fish Blog - http://GoldLenny.blogspot.com (Links to articles referenced above listed on the right side under Archives - Year, Month and under Labels)
Category: Philippines Internet Koi Society
