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Discussion Starter · #1 ·
The pH of my tap water is at least 8.4 straight from the tap (possibly higher; impossible to tell with those garbage API test cards).

The pH of the water that's been cycling in my new tank for over a week is somewhere between 7.4 and 8.0 (again, impossible to tell using the garbage API test card).

Why does pH drop like that over time? How should I treat it? (And for cryin' out loud, why doesn't someone invent a better test?!)

I think my rocks are some kind of mudstone, which doesn't affect pH. My substrate is Eco-Complete Cichlid Sand, which is supposed to help maintain high pH, but evidently doesn't.
 

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Did you try taking a sample of the tap water in a clean glass container and leaving it set out 24 hours before testing? If not, try it. Some tap water will change in pH after it off gases after 24 hours and some does not.
 

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I think it's not uncommon for pH to be a little different in settled water vs. straight from the tap. You can test untreated running tap water vs. untreated tap water that has sat for a little while. The rested water is what you should consider your baseline. (pedit: deeda ninja'd me)

After that there are many things that can drive pH lower by consuming buffers in a setup. Usually they don't happen until you've got fish and a nitrogen cycle established. But if you're cycling does that mean you've added ammonia to start your nitrogen cycle (ie fishless cycling)? that could have an effect. Are you heating your tank? warm water vs. cold tap water can have different quantities of dissolved gasses like O2 which can effect pH. Have you added water conditioner? does your tap have chloramine or just chlorine (or none if you're on a well)? Have you tested for KH (buffers)? if they're low or non-existent, you might be more susceptible to having your pH fluctuate, for example starting high, lowering as your filtration converts fish waste to nitrate, and then jumping back up again when you water change.

Your location being Ohio, if you're on Lake Erie water like me, you're likely just fine for rift like cichlids out of the tap without doing anything special to the water for pH.
 

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Discussion Starter · #4 ·
Rhinox said:
I think it's not uncommon for pH to be a little different in settled water vs. straight from the tap. You can test untreated running tap water vs. untreated tap water that has sat for a little while. The rested water is what you should consider your baseline. (pedit: deeda ninja'd me)

After that there are many things that can drive pH lower by consuming buffers in a setup. Usually they don't happen until you've got fish and a nitrogen cycle established. But if you're cycling does that mean you've added ammonia to start your nitrogen cycle (ie fishless cycling)? that could have an effect. Are you heating your tank? warm water vs. cold tap water can have different quantities of dissolved gasses like O2 which can effect pH. Have you added water conditioner? does your tap have chloramine or just chlorine (or none if you're on a well)? Have you tested for KH (buffers)? if they're low or non-existent, you might be more susceptible to having your pH fluctuate, for example starting high, lowering as your filtration converts fish waste to nitrate, and then jumping back up again when you water change.

Your location being Ohio, if you're on Lake Erie water like me, you're likely just fine for rift like cichlids out of the tap without doing anything special to the water for pH.
Yes, I'm fishless cycling with ammonia. In fact, I'm already converting ammonia to nitrite in 24 hrs. Now I'm waiting for nitrite to convert to nitrate.
Yes, I'm heating my tank. I currently have it at 84-degrees F, because I was told high temperature helps speed growth of the nitrifying bacteria.
Yes, I added water conditioner (Kordon Novaqua Plus) to my tap water when I filled the tank nearly 2 weeks ago; have not added anything since (except ammonia).
No, I have not tested KH yet. My KH test liquid is expired. Waiting for new test bottle to arrive. (In my experience the API KH test is not accurate anyway.)
Tap water that has been sitting out in a 5-gallon bucket for several hours has the same pH as straight from the tap: at least 8.4 (possibly higher).
Tap water that has been sitting out in a 5-gallon bucket for several days has pH of 6.8 or 7.0.
The water in my cycling tank has pH somewhere between 7.4 and 8.0 (impossible to tell using the garbage API test card).
 

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Try aerating the bucket to get the accurate pH reading faster than several days.

Not the fault of the test...the chemical in the water outgasses after it exits your tap and has a chance to breathe.

I take my API test card and tube out in the sunlight and lay the tube across the various color swatches. Choose the one that is closest...or extrapolate if result is between colors.
 

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Discussion Starter · #6 ·
DJRansome said:
Try aerating the bucket to get the accurate pH reading faster than several days.

Not the fault of the test...the chemical in the water outgasses after it exits your tap and has a chance to breathe.

I take my API test card and tube out in the sunlight and lay the tube across the various color swatches. Choose the one that is closest...or extrapolate if result is between colors.
I agree that the different pH levels from the various sources (cycling tank vs. aged several hours vs. aged several days) is not the fault of the test kit. I never said that. What is the fault of the test kit is the impossibility of getting an accurate reading from the test cards. For example, on the high-range pH test card, 7.4 is darker than 7.8, and almost the same color as 8.0. (And don't even get me started on the nitrate test card, where 10ppm and 20ppm are the same color, and 40ppm is darker than 80ppm.) And no, I didn't get a defective test kit. I've been buying these kits for 20 years, and the color squares have always been inconsistent/inaccurate. Moreover, trying to compare the color of a translucent liquid to a solid printed color just doesn't work. The colors in the test tubes will never match the color squares, because they are two inherently different color saturation densities. What we need are test kits like some swimming pool test kits that have translucent plastic color squares that actually match the color saturation of water.
 

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I feel your frustration on reading the kit. 1 trick I used to do was to use a medicine dropper to make sure I was getting the precise volume of the sample, and then making a few other test tubes mixed with tap water at known ratios. That way I could have a few different data points with which to make a better guess at the true reading.

It works with ammonia and nitrate for example but probably not pH tho.
 

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I wholeheartedly agree with your observations of the API test kits. They are terrible. Personally I have not found another better option for FW use. If you check out any of the SW forums, SW API kits are the worst for SW application. Once your tank is cycled, ammonia and nitrite FW API tests are easy to read as those will(should) be zero. PH and Nitrate are a different story. I think the key is to establish consistency with water changes to avoid massive fluctuations. I am on well water and premix my water the night before water changes adding the buffers/salts to achieve the desired parameters using airstones to expedite the gas exchange. My tap tests 6.0ph but ends up resting around 7.2 with gh and kh unaffected before additives. It took quite a few tests to figure out the amount of salt/buffer I needed to raise it where I wanted but now it is quick and easy. As for nitrate, I test almost daily and do as many water changes as necessary each week to keep it the lightest orange and out of the red. For PH I did purchase an Apera device for comparison against the API test for piece of mind but that is an added expense and then it needs to be kept calibrated. I really don't use it too often any more.
 

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TROK4614 said:
For PH I did purchase an Apera device for comparison against the API test for piece of mind but that is an added expense and then it needs to be kept calibrated.
I use a pH meter myself, never liked the API tests. Had to go through several meters before finding one that was accurate and easy to re-calibrate.
 

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Discussion Starter · #10 ·
I'm glad to see I'm not the only one who recognizes the flaws with the API tests. And yes, with a little bit of trial-and-error when first setting up a tank, followed by consistent water changes and filter maintenance, etc., most hobbyists settle into a routine that works to keep water parameters in good shape. Indeed, my planted tank has pretty much been running on auto-pilot for about 8 years. I haven't done any water testing for so long that my test fluids all expired several years ago. But just think how much easier that initial set-up process would be if we had a better, more accurate test kit.

Getting back to the original topic, my current situation is pretty interesting. Straight from the tap, my water's pH is off the chart, but after aging it in buckets, it eventually seems to settle down to near neutral (7.0). But then, once in the tank (still cycling), it has a pH somewhere between 7.4 and 8.0. So maybe my rocks/substrate are raising it back up a little bit, though not quite to that perfect 8.2 that I'd like to see.
 

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Hey Smeagol,

This is totally normal. It is the creation of Nitric Acid in the cycling process. I believe it's being so pronounced because of the amounts of nitric compounds you're dealing with during fishless cycling. Normally you wouldn't see this because the numbers aren't as big and you'd do water changes. In the planted tank world, you may have heard of this as "Old Tank Syndrome" where nitric compounds which have built up over time cause a pH crash. .

See my long post on your cycling question, but it's the reason I was stopping the cycle in my box - Too much nitrogen made nitric acid and dropped the PH below 6.0 at which point it's almost impossible for BB to grow. I compensated in my case by adding cichlid salts to keep the buffering capacity of the water up and changing it out when nitrates got over 200 ppm. I was dropping mine from about a solid 7.8-8 to under 6. At this point, the API test wasn't really able to tell me with any certainty what the pH actually was. Has anyone else ever had this problem? I mean with these tests? Anyone? :D

Love always, Precious
- Deagol
 

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Discussion Starter · #12 ·
Finally got my GH and KH test kit. Here's the hardness of my tap water:

Tap water GH = 8* (143ppm)
Tap water KH = 3* (54ppm)

Are these readings low enough to warrant use of salts/buffers?
 

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KH under 4 can give you pH fluctuations. I would try crushed coral in your filters to see if that buffers your water enough to keep your pH level.
 
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