Does this mean my test kits are off?

[cgcaver]

Im gonna post 3 sets of numbers for you guys, but I think the only ones that should really matter are for the Distilled water. Can y'all help me determine if my test kits are off, and future readings should be compensated for?

Tank

pH - 6.8
gH - 4
kH - 8
NH4 - 0ppm
NO2 - .25ppm
NO3 - 20-30pm
PO4 - 5ppm


Tap Water

pH - 7.6+ (my kit only goes this high, but I think my tap water is about 8.2)
gH - 2
kH - 6
NH4 - .5ppm
NO2 - 0ppm
NO3 - 0pm
PO4 - 1.0ppm


Distilled Water

pH - 6.0 (Shouldn't it be 7.0? This is one of the tests I was concerned about)
gH - < 1
kH - < 1
NH4 - 0ppm
NO2 - 0ppm
NO3 - 0pm
PO4 - .5ppm (Shouldn't this be 0? Another test I was worried may be off)



~ Thanks for your help guys.

 

[LittlePuff]

Where did you get the distilled water?

Kim

 

[Fishyfanatic]

Does your local water source use Chloramines instead of Chlorine? If so, that could account for the Ammonia reading in your tap water. The pH sounds right, it will normally lower after the water has been sitting overnight.

What kind of test kit are you using?

 

[cgcaver]

I got the distilled off the shelf at the grocery store.

I have aquarium pharmaceuticles (sp?) test kits.

I honestly don't care much about my tap water at all, but I was really concerned about the distilled readings, since I figured they should all be dead neutral.

 

[An t-iasg]

The Aquarium Pharmaceutical kits are good ones. How long have you had the kit - how old is it? They don't have expiration dates but I write the date that I buy it on the box, and when it's about a year old, I buy a new one.

I don't think your distilled water pH is off, though. I mix tap and RO water for my tank (my pH out of the tap is 8.2) and my RO pH is 6.2 or 6.4. I always thought that RO water and distilled water are neutral too, but my RO water is always on the acidic side.

When are you testing your tap water pH? Like Fishyfanatic says, you should test the water after it's been sitting out, at least overnight. This is called "aging". After aging, my tap water pH is 7.8 (it was 8.2 out of the tap).

Your tap water seems similar to mine. I'm wondering if you mixed up your KH and GH values. My KH (of tap water) is 3, and my GH is 9. I also noticed that your tank has a nitrite reading of .25. Is the tank cycled? Double-check the reading again and do an extra water change this week if you're still showing nitrites.

 

[hashbaz]

Could CO2 account for the PH of "pure" water not being 7.00?

 

[QTOFFER]

http://www.epa.gov/airmarkets/acidrain/experiments/exp1.html

This should explain why your distilled water pH reading seems off - scroll down to the last paragraph. Kudos to hashbaz!

Household detergents contain phosphates that never completely leave a piece of washed glassware no matter how much you rinse it. Was your distilled water sample stored in a washed glass?