Tap pH fluctuations.

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jessebs

Aquarium Advice Apprentice
Joined
Sep 24, 2012
Messages
47
Location
Manitou Springs, CO, USA
I'm setting up a new tank and have been cycling since September. About a week ago, my cycle stalled and my pH was very low, most likely caused by driftwood in my tank.

Based on some suggestions here, I put in some crushed coral into my filter on Wednesday. It was just a tablespoon or 2 into a nylon bag. Afterwards I did close to 100% water change.

I've been testing the cycle, and it looks like it's back on track. Today I was ready to say it's done, so I tested all params. My test showed pH off the chart (above 8.8). My first thought is that I put in too much of the crushed coral, so I pulled out about 1/2, did a 70% change and tested again to see if it brought it down enough. Again, off the chart. I don't think it's a bad test kit because both pH and high-range pH show off the charts.

I test my tap. My pH is now over 8.8 from the tap. When I tested to get my baseline in October, it was 7.6. I guess for now I need to pull out the rest of the crushed coral, and the driftwood should bring it down.

This leads to several questions

Do I have any way to protect against pH swings like this coming from city utilities?
Has anyone had a similar experience?
Wouldn't doing a water change like this kill any fish that I have since it's a pretty substantial swing?
Does argonite actually raise pH or just increase buffers so it's less susceptible to change?
 
So you're telling me you have 8.8 pH of tap water(Fresh)? Thats way to alkaline for any type of fish. Even if you used a product to reduce the pH, the max you can do to reduce is .5 per day, because the shock would be too high. Also, don't use water bottles as alternative. Just make sure to have a back up plan like some reserve water with a stable pH.
 
I'm setting up a new tank and have been cycling since September. About a week ago, my cycle stalled and my pH was very low, most likely caused by driftwood in my tank.

Based on some suggestions here, I put in some crushed coral into my filter on Wednesday. It was just a tablespoon or 2 into a nylon bag. Afterwards I did close to 100% water change.

I've been testing the cycle, and it looks like it's back on track. Today I was ready to say it's done, so I tested all params. My test showed pH off the chart (above 8.8). My first thought is that I put in too much of the crushed coral, so I pulled out about 1/2, did a 70% change and tested again to see if it brought it down enough. Again, off the chart. I don't think it's a bad test kit because both pH and high-range pH show off the charts.

I test my tap. My pH is now over 8.8 from the tap. When I tested to get my baseline in October, it was 7.6. I guess for now I need to pull out the rest of the crushed coral, and the driftwood should bring it down.

This leads to several questions

Do I have any way to protect against pH swings like this coming from city utilities?
Has anyone had a similar experience?
Wouldn't doing a water change like this kill any fish that I have since it's a pretty substantial swing?
Does argonite actually raise pH or just increase buffers so it's less susceptible to change?

Are you sure this is the true pH? Try testing your tap water after 24 hours and stirring it every now and then during the 24 hours and allow it to gas off. Then see if it's still 8.8
 
Even so, my tank was just as high with only a tablespoon or two of crushed coral. To me, that definitely points to a water problem, unless both pH tests are bad.
 
Sometimes PH can change from what it is out of the tap and testing it from the tap doesn't give your true PH. Try leaving out a glass of tap water out for 24 hours (stir it occasionally) and then test PH; this is your true PH and what your tank's PH should be. For example, my tap PH is 8.4 but it gasses off to 7.2 which is what my tank's PH is. If the two numbers are very different like mine and you test right after a water change, the water will test at the PH from the tap, not the gassed off PH so that isn't too accurate.

If the true PH test (tap water sitting for 24 hours) is a lot different than your normal tank's PH then you may have just added too much coral (when you removed the coral how long did you wait to retest? It would need to circulate a while before the PH would stabilize again). Sometimes the water municipalities change things too so the PH might be different now than it was before if they're treating the water differently, so you may not need the coral at all. It'll be easier to tell once you do the 24 hour test.
 
It did gas off down to 7.4. When I got my baseline no gas off happened. Thanks for the feedback everyone!

If I do a water change with tap water will it hurt the fish, or is it essentially a false pH reading until the gas off happens?
 
I wish people would just add buffers to their water then add their water to the tank. It is so much easier to get a precise reading.

You have no idea with crushed coral what you are going to move your KH & pH to, since it is not precise. Once you reach your desired level, if the crushed coral remains it will continue to dissolve into your tank until you reach a pH of about 8.2. Also, you are adding water during water changes that is not of the same parameters of the tank water.

Scrap the crushed coral. Test your tank's KH, test your tap water KH. Add 1/4 tsp of baking soda per 5 gallons of water to increase your KH by about 1.5 degrees. Do this once per day until you reach your desired KH. Once you reach a KH of 6 or 7 or whatever you desire, stop adding baking soda to your tank.

Now you know your target KH. Add baking soda to your tap water during water changes to increase the KH of your tap water to match what your current tank water is. For example, if your tank is a 20 gallon tank with a stable pH and a KH of 8 and your tap water has a KH of 3 and you are changing 25% of the water (5 gallons) then in a 5 gallon bucket of tap water add about 3/4 tsp of baking soda along with your water conditioner and add to your tank. You know precisely what you are doing and what the parameters are.

Or you could just keep guessing and hoping with a bag of crushed coral.
 
I guess that means I need a KH test kit, which I should probably have anyway.

How does that work with something like a python? Can I just add the baking soda to the tank directly after the tap water is added?
 
I guess that means I need a KH test kit, which I should probably have anyway.

How does that work with something like a python? Can I just add the baking soda to the tank directly after the tap water is added?

Yeah. Thats pretty much the only way.
 
Neither of the stores I tried today had kH tests. pH is also steady at 7.4, so I think the coral is working out.

Wednesdays are my weekly water change day, so I'll change and just keep an eye on everything.
 
I'd just keep the coral in there. I keep some in my filters since my water is pretty soft and I've never had the PH rise on me from the coral dissolving. Also water changes shouldn't be an issue. My tap's PH is 8.4 and my tank's PH is 7.2 and I do 50% weekly water changes without issue to the fish, so I think it'll be fine.
 
I'd just keep the coral in there. I keep some in my filters since my water is pretty soft and I've never had the PH rise on me from the coral dissolving. Also water changes shouldn't be an issue. My tap's PH is 8.4 and my tank's PH is 7.2 and I do 50% weekly water changes without issue to the fish, so I think it'll be fine.

What do you do to bring your pH down from 8.4 in the tap to 7.2 in your tank? Are you using straight tap in your tank?
 
What do you do to bring your pH down from 8.4 in the tap to 7.2 in your tank? Are you using straight tap in your tank?

Yep straight tap. Once the water gasses off the PH drops on it's own, that's why it's generally recommended to leave a glass of tap water out for 24 hours and then test PH again as the PH out of the tap can change when the water gasses off. I still do water changes right out of the tap though and the PH difference doesn't seem to bother the fish any.
 
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