Weird Water Parameters

[DougAdel]

I've had my 20 gal tank set up for about 8 months now. I did a full fishless cycle with ammonia and after a small battle with some parasites everything has been hunky dory.

I have 2 penguin HOB filters and have been running 0 ammonia 0 nitrite and about 10 nitrate since the introduction of 2 bolivian rams and about 8 peppered cories. The rams don't get along, but have their own areas set up and have never had any real issues. They both eat well and frolic to the front when it's feeding time.

One thing I've learned from forums and LFS is to not play around with ph as it is better to have a stable ph then to mess around and have fluctuations. I hadn't checked my ph in quite some time so during some routine maintenance I decided to give it a go. Knowing that we have hard water in Edmonton i expected it to be around the 8.0 range, but the test instantly went dark purple closer to the 8.6 range. Thinking this was high I did the kh test and ended up adding about 2 drops before it turned blue (approximately 2dKH and 35.8 ppm GH/KH). I tested again today and got 8.4 on the ph and the same numbers from a brand new kh test (the other had expired so I thought I should get a new one).

The water parameters are the same today 0 ammonia 0 nitrites and about 10 nitrates. Why is my ph so high when my kh is so low? I always thought we had hard water in Edmonton, but it's coming out 1 drop to turn blue from the API KH test. The fish are behaving normally, but with the low KH I am worried that the ph has been fluctuating for quite some time and that I've done some long term damage.

Any thoughts? Should I add some alkaline buffers (I don't want the ph to go any higher though...).

EDIT: there is currently no driftwood or anything like that in the tank. I could easily put some in and I also have some indian almond leaves hanging around I could throw in too, but I'm not positive they would have any real effect.

Edited August 25, 2013 by DougAdel

[ckmullin]

you said no driftwood (that should make things acidic) how about rocks and substrate?

[creekbottom]

Make sure you know the difference between gH and kH, something you may be getting confused and it's effects on pH. Google comes up with lots of explanations on the difference. Also, you can check Edmonton's water quality, Epcor reports publicly and they are available online, google 'Edmonton water quality reports.'

I would also test the tap water or whatever water you use for water changes and compare that to Epcor so that you have some idea of the validity of the test kit.

[DougAdel]

I have some Tahitian moon sand as a substrate and have a few rocks in the aquarium as well for little caves. I did the "vinegar test" on the rocks and saw no bubbling, but I kind of doubt the validity of the test.

My understanding of gh and kh are pretty limited. I know gh is general hardness and is basically the measure of a bunch of elements that are normally found in water. kh I'm fairly certain is just dissolved carbonate. How these measurements effect ph is due to hydroxide ions being formed which is usually a direct result of kh. The actual chemistry equations I have no idea on, but this is my very basic understanding of what's happening in my tank.

I googled the water quality from the tap and my hardness test is WAY off (I assume ppm = mg/l) which would make more sense, but I just bought the blasted thing today. My ph tests were pretty similar to that of Epcor's. Do you think it could be another faulty kh tester? I bought the API one...

[jvision]

If you're just using tap water for your WCs, I don't really see how your kH could be way lower than Epcor... I think the test kit is suspect. I would see if you could get your money back.