Ph Steadily Rising

Discussion in 'pH' started by rvanatta01, Jun 12, 2019 at 9:54 AM.

  1. rvanatta01 New Member Member

    Hello all,

    I recently built the tank pictured here. As I'd like to put Neon Green Rasboras (6.0-7.0 PH) in the tank, I chose to use distilled water with a PH of ~6.0 to fill the tank and have changed the water twice. The tank has been active for almost 2 weeks now and the plants have been in it for almost 1 week. The composition of the tank is as follows:

    Substrate: Seachem Black Flourite
    Rocks: Quartzite hand picked (tested with muriatic acid -no bubbling)
    Plants: Foreground -Dwarf Hairgrass mid -Roundleaf Lindernia
    Lighting: Nicrew LED @6500k

    I've fertilized the plants twice with Seachem flourish and they seem to be doing just fine. Unfortunately, I've been measuring PH, and it has been gradually increasing. Yesterday it read 7.52 and today it was 7.63 and has continuously been trending upwards since the last water change. Any ideas what can be causing the steady increase in PH? My first thought was the rocks, though I do feel that I took proper precautions testing them with muriatic acid prior to putting them in the tank. I know plants can cause a 'slight' increase in PH, but it doesn't seem it would account for how much it has climbed.

    Any help/thoughts would be much appreciated.


    Attached Files:

  2. Anders247 Fishlore Legend Member

    Welcome to fishlore!
    Do you know your KH and GH levels?

  3. Skavatar Well Known Member Member

  4. rvanatta01 New Member Member

    I do not yet have a way to measure GH/KH levels.

    Good to know about the fertilizer. I suppose it should stabilize soon which would determine if that is the source. My only worry is that it continue to rise. Just want to make sure I'm not missing something obvious.
  5. Skavatar Well Known Member Member

    from Seachem's website

    Calcium (Ca) 0.14%
    Magnesium (Mg) 0.11%

    Both of these elements contribute to higher GH, but not sure if it will increase the pH that much.
  6. rvanatta01 New Member Member

    Thank you for the info. If it does not stabilize over the next couple of days I will likely try removing the rocks. I don't know what else would contribute to a high PH as the Flourite is supposed to be neutral. And I don't imagine the acid test being an exact science to measure the rock's full composition.
  7. oldsalt777 Well Known Member Member

    Hello Ryan...

    Are you keeping demanding plants? Did you know low to moderate light plants don't need added fertilizers? They'll grow fine with the fertilizers the fish produce and lighting from the local hardware store. Putting chemicals into the tank water will surely affect the water chemistry and cause pretty dramatic changes in the pH. Fish won't last long in unstable water conditions. Check the lighting requirements of your plants and see if they need added ferts and gradually work up to the point you change out at least half the water weekly. This is all the fish need to be healthy.

  8. rvanatta01 New Member Member

    Thank you Old, the plants I have in the tank are Dwarf Hairgrass and Roundleaf Lindernia. My understanding is that both plants require "moderate" lighting. I decided to use fertilizer because I'm hoping for the grass to spread and fill out the tank but perhaps I'll hold off on the fertilizer and add only as needed. Much appreciated.
  9. GadgetGirl3 New Member Member

    If you're using distilled water, you absolutely have to remineralize the water with something like SeaChem's Equlibrium. Plants and fish won't thrive in distilled water. Distilled water has extremely low KH and will result in wild pH swings.
  10. rvanatta01 New Member Member

    That's good to know and makes obvious sense now that I think about it. I guess the question would be whether tap water would be more resistant to climbing in PH? Or does KH mostly provide resistance just to PH decrease?
  11. Loetje Valued Member Member

    KH is a measure for the carbonate ion. It acts as a pH buffer, so it provides (most of) the "pH-swing-resistance".
    It is a place for hydromium ions to lose their acid-component (the H+), or for hydroxide ion(OH-) to recieve an H+.
    Distilled water is mostly H2O and will swing wildly in pH except if its sealed hermetically from the environment, which your tank isnt.
    Tap water will have more buffering capacity than distilled water.

    If you still want to use distilled water for whatever reason, you need to remineralize it as suggested.

    In my high-school days, I drank a couple of bottles of distilled water. I got a huge headache. Just sayin':)
  12. GadgetGirl3 New Member Member

    I don't claim to be a water chemistry specialist as it's a very complicated subject. KH is what provides the buffering and the ability to resist pH changes. It's also called alkalinity (not be confused with the term alkaline, or buffering capacity and is a measurement of the carbonates and bicarbonates. Distilled water has zero KH and pH shifts are going to be wild. It also affects the osmotic pressure across the fish's membranes. Very hard on fish and plants. Distilled water is near perfect if you add Seachem Equilibrium which I strongly suggest you do. Is there a reason you don't want to add tap water? Most tap water, but not all, is fine for most anything you want to keep or grow. But before you switch to tap water, get an API test kit for KH and GH and test your tap water. But definitely get you some Equilibrium ASAP if you continue with distilled. I think you'll see your pH stablize. You may want to work up to a full dose of Equilibrium so as not to shock your fish! Good luck!

    Edits: typos
  13. Wraithen Well Known Member Member

    The headache was likely in your head, from something else, or you are literally starving. With our diet we dont need anything in the water. Many people in my area drink rodi as it's far safer than the firefighting chemicals in our water table.

    Also, kh does more than just keep the ph stable, it does so in one direction. More kh = higher ph. There is not really a law for kh = certain ph though. It depends on the water to begin with. However, high kh guarantees high ph. You cant have one without the other.
  14. GadgetGirl3 New Member Member

    Regardless of the issues with drinking distilled water, the OP absolutely has to remineralize the distilled water if she/he wants to continue using it.
  15. Loetje Valued Member Member

    Haha, I realized I never questioned it. I drank the water, got a headache, associated it directly with it, and accepted it at an absolute truth..
    Thanks for updating some old and bad info.

    On topic: I agree; the KH is more than a buffer. Would like to add that pH-KH link is dependant of the origin of the carbonate. If it's CO2 injection, it should lower pH:
    CO2+H2O -> H2CO3 -> H + HCO3
    Or am overlooking something?
  16. rvanatta01 New Member Member

    Thanks all, this discussion is helping a lot. Seems I should have done a bit more research on KH rather than focused solely on PH. My line of thinking was that due to its purity, at least I know what is in distilled water, but it seems that adding the extra step of mineralizing the water could be averted by simply using tap (PH: 7.0). Considering the fish I'd like to keep thrive mostly in lower PH (6.0-7.0), i'll have to just wait to see what the tank stabilizes at once I switch to tap, then reformulate my plan based on that. Currently no fish are being harmed in this process due to there being none in the tank :p and the plants actually seem to be doing just fine.
  17. Wraithen Well Known Member Member

    You are correct about the carbonic acid created with h2o and co2. I dont think that co2 counts as a part of kh though, just because kh is carbonate "hardness", not all carbonate.
  18. Loetje Valued Member Member

    Well, this maybe off topic (sorry OP :))
    The HCO3 and possible subsequent CO3 both count on the KH scale. Didn't really know for sure, so I checked wikipedia.

    So in all that should mean:
    1.) if the carbonate ions come from calciumcarbonate, magnesiumcarbonate or something like that (which I assume is the most common in fish tanks), it will raise KH and raise pH. (In short: CaCO3 + H2O -> HCO3 + OH + Ca)
    2.) If the carbonate comes from baking soda (NaHCO3) or something similar, it should raise KH and lower or raise pH dependant of current pH (in acid, it would raise pH (In short: NaHCO3 + H -> Na + H2O + CO2), in base it would lower it: (in short: NaHCO3 + OH -> Na + HCO3 + H2O))
    3.) If the carbonate ions come from injected CO2, it should raise KH and lower pH (in short: H2O + CO2 -> H + HCO3

    Thats what I remember from chemistry:)
    If I missed something, do let me know!

    Have a great day.