Hi..I am back and with a pressing problem. We are preparing to go out of town for medical tests unfortunately and 3 of my 7 aquariums have ph problems. Can't figure it out. A local animal feed/fish shop says I might have PH Block whatever that is and might need to get all new water. I have a 40
gal 4 turtle tank, a 60
gal tank with 1 Oscar, and 2 10
gal baby guppy/algae eater/pleco tanks with no issues. The guppy and turtle tanks get lettuce everyday on a clip. My 42
gal bow front mixed tank (plecos, clown and golden loaches, flying foxes, green corys, synondontis cat) get lettuce daily also, and I have a 5 gallon tank with a tiny withered golden loach that I have nursed for two years, 4 small corys, and a couple of guppies---no lettuce in that one. These two tanks as well as a 15
gal column tank with mainly guppies and flying foxes have low ph---like 6. After a partial water change it comes up, but not for long. I have put ph up drops in carefully. All tanks get 1/4 to 1/3 water replacement and Python vacuuming every week. The turtle tank, which also has a few guppies, gets nearly a total water change. What can I do about those three tanks? I can't figure out why I can't get the ph up? Please help! Is there anything I could do---we are leaving tomorrow for a weekend of medical testing. My neighbor will look in on them Friday morning, we'll be back Sunday am....No pet shops here. Got some ph correct tablets is all--and someone suggested a pinch of baking soda? Can't do much because we are leaving. I noticed a couple of guppies died in the 5
gal and that alerted me to the ph. Then I started checking all of them, etc. These 3 tanks routinely want to be at 6 or below I'll bet. I am using drops and testing and retesting---even with different bottles. Our tap water is at 7. I use Prime when doing partial changes. Would sure appreciate any quick advice, and then I can do more extensive treatments after the dr visits!

PS...Ive had all these tanks with no probs for over 2 years. I have heard that the city water ph used to be 7.6 or so instead of the 7 it is now?