pH question

[Stacey]

I noticed this morning that one of my filters stopped........ don't know how long it was out for but ammonia registered 0.25 or less. (was slightly lighter green that 0.25) I did the full range of tests and and nitrite was 0.25 (again a little lighter purple, so probably a little less) and nitrate was 10. This tank (along with all the others) had it's substrate changed from gravel to sand last week, as a result I did not change the filter cartridge then. My tanks are all usually at about 7.6, a light green on the Nutrafin high range pH test card. (All other tests are API) This time the pH test came out YELLOW, not even on the colour chart! I did a 50% water change, replaced the filter cartridge, did not add any new peat, as usual, due to the pH test results.

Tank is 10 gallon, with a Whisper filter (for a tank up to 20 gallons) and stocked with a betta and several baby ramshorn snails. (Exactly how many I'm not sure,) it also contained some of those "surprise snails" commonly brought in on plants, but I got real sick of the way they just showed up with no visible egg sacks for me to cull, and I fed my oscar a live meal tonight.......... shhh don't tell my kid!

Can anyone suggest a possible reason for the pH drop? (The test is not off, other tank tested as usual)

[Tanker]

Possibilities abound, but there is a correlation with an ammonia spike and pH. Did it come back up after the water change?

The pH test you have is a high range test for 7.0+; chance that if the test registers less than it's threshold on the scale, it simply doesn't register anything at all (and so you get a yellow that looks WAY off the charts). Eg. it may have only been at 6.7 but as it was lower than the 7.0 the test reads, it would give a false reading. I am not familiar with the exact chemical process of that test, but it sounds good in my head. The presence of a measurable amount of ammonia in the tank may have also skewed the results enough to give a false reading.

[werner]

What kind of gravel did you get rid of? It may have been buffering the water, and removing it allowed the pH to drop.

[Stacey]

Crisis apparantly averted. This mornings test results are ammonia and nitrite 0, nitrate 5. pH 7.4. A little lower than I expected for pH, but a test on the tap water revealed 7.6. The last time I tested the tapwater pH was 8.0. This was probably many months ago. I will continue to keep an eye on it. I must admit these last few months I have not used the test kits much.

Tanker, your explanation about the pH test results makes sense. The lowest the test reads is 7.4. So I don't know if it was a severe pH drop or if the results were just wonky. Fish and snails seem fine.

I have also rehomed some of the larger snails. Now there are about 20 ramshorn babies in there, all dime size or smaller. This has the added advantage of all the ramshorns old enough to breed are in one tank now, which makes egg removal easier. So, anyone want any snails?? Got a never ending supply here.

Werner, fairly sure it wasn't the gravel buffering the water........ it was that artifical painted stuff. I chose that gravel back when I was new to fish and knew that some gravels would affect the pH. The painted stuff was supposed to be inert. Now that I've been doing this for about a year, I feel I've graduated to more natural looking aquariums. (Although I still use plastic plants in with the ramshorns)