Huge pH Crash!!

[Jayann]

I am on day 16 of my 10 gallon fishless cycle. I am close to being complete but not quite there because I am not yet processing the ammonia in a 24 hour period. It is more like within 36 hours. Additionally, I have no nitirite readings ever. I guess because of my seeding material, my cycle went directly from ammonia to nitrate. Things have been going exactly as planned. I knew a 50% water change would be due soon because my nitrates were starting to read towards the high end of the chart (API Freshwater Master Kit) but, they were not quite yet off the chart and could still be read, I had not yet done the change. My pH has been dropping but literally ever so slowly. At first I had an issue with it being high after adding crushed coral (which i very shortly thereafter permanently removed) as the suggested insurance because my source water pH was quite low at 6.4. I started getting high pH readings after this which I didn't realize at the time the ammonia could raise it as well. Anyhow, I ended up doing pwc at that time to try and get the pH in a healty range for growing bacteria. It maintained at 7.8 for a short time after and then remained very steady at 7.6 ever since. Over the last few days it dropped down to 7.4 which didn't alarm me at all. Then down to 7.2 for a day. Suddenly within my last test around the 21 hour mark, my pH dropped from 7.2 to 6.4. Now I read this can be an issue towards the end of the cycle. I read about the buffers being used up and that doing a 50% water change would restore them. I bought a GH and KH test but do not understand how to read the results, nor what they mean. I do however know, this may be part of my issue if they are low from what I have read. So far since doing the pwc I have added my prime, tested my ammonia, dosed it back up to 4. I don't want to check the pH yet because I know the ammonia will be throwing it off. When can I safely test that all has settled and filterd though enough to be getting accurate readings on the pH ammonia and nitrates after a pwc. Furthermore, is this going to be a continued issue or was this the big "oh its time to change some water" moment I read about and all will be well again with my numbers and the cycle itself?

 

[Mebbid]

It's common for the pH to drop during a fishless cycle and a water change easily fixes it. I'm not sure about the GH test kit but I know the kh test measures by the numbers of drops. There should be a chart in the instruction book.

Overall it's not as big of a deal as it seems and you already fixed the problem by changing the water