I have not written in a while but I thought I would open a thread and share with you my experience so far managing a PH spike in my 20 Gal tank. To review my situation, 20 gal long freshwater tank started in August and fully opoulated by October. My town water has always been very high in PH, at least 7.6 or higher, and it tends to go towards 8 after 24 hours of bubbles. It is also very hard and buffers any attempt at lowering the ph. So, my regime has been to use Neutral Regulator in fairly large doses with each water change and until mid January I was able to keep the tank between 7.0 and 7.2.
In January I noticed the ph moving toward 7.4 and also problems with the fish. I called the folks at API and they recommended I increase the neutral regulator further, which I did. What I did not do, was continue testing the change water each time. Something very significant has changed in the formula of my town water. By early Feb the ph in the tank was off the scale high, north of 7.6, and the algae was running mad. (I since learned that the algea goes mad when you use phosphate buffers.) When I started testing my tap water again I found it was now near 7.0 from the tap, moved to 7.2 with aeration, but when I added neutral regulator it actually went UP to near 8.0. So, by ading extra NR I was driving the ph the wrong way. I called API back, and they had no idea what it was. They told me to stop using NR and gave me an alternate formula of Alkaline and Acid buffer that now seems to stabilize the change water right at 6.8 - 7.0. I put the change water in 5 gallon pails, aerate it for 48 hours, and add the buffers to it many days before using it in the tank.
The last few weeks of water changes has moved the ph down to 7.2 and I hope to get it further to 7.0 eventually. What I don't understand is:
1) What happened to my town water that it changed it's entire chemistry?
2) Why does neutral regulator drive the ph to 8.0 now?
3) Now that my town water tests closer to 7.2 can I just stop adding all this stuff to it, and maybe just give it a touch of acid buffer to lock it at 7.0? Do I really need to buffer in both directions with hard water?
4) What are other people's experiences with Acid buffer and Alkaline buffer and what amounts do you use? How much is too much?
Any of your thoughts would be appreciated. I have lost a couple more fish, but overall everyone seems much happier again in the tank now that I have it down around 7.2.