pH not stable

[Pjh4427]

Hello guys. I have a 75g tank with 7 discus. My question is I am having issue with my pH and kH.I can’t figure out what making my pH/kH drop. My aged aerated tap water pH is 7.9 and kH 4. I did a 100% WC the day before I got my discus and the pH was 7.9 and kH of 4 but the next day my pH was 7.6 and kH 2. I noticed my pH/kH keeps dropping every day. I am doing 30% wc every other day but still pH/kH still dropping. Right now it is pH 7.3 and kH=1. I wonder what I need to do to stabilize my pH. I am thinking adding crushed corals in it and I want to know how to do it, if any of you have experience using crushed corals to stabilize pH please let me know how. Thanks

[Charlyc11]

You need to give more info about the tank than 75g 7 discus. Planted, BB, filtration, aging time, cycle......
Crushed coral won't help on PH above 7 I have corals in mine since it's hovering on PH 7. I am not an expert but a lot of people here have been keeping Discus for decades.
Added:
I just read your first post and as a newly cycled tank you bacteria must be working overtime keeping up with your new 7 discus. Make larger water changes so the bacteria can catch up with the bioload. Those are my thoughts maybe somebody else can guide you better.

[LizStreithorst]

Do you age your water?

[dspeers]

Bottom line is that between the food and fish waste you are adding acidic compounds that are dropping your pH and kH together, adding a buffer is a short term fix at best with long term consequences as your cation (calcium in the case of coral) will constantly increase as you chase your pH. As an aside your fish also produce NH3 which is basic but is almost immediately converted to NO2 and then NO3 which is also acidic. Better to increase your water change volume to stabilize both pH and pK. Start at 50 % and see what your pH and kH are pre and post water change. Also, you indicated aged water, how long and what are the pH and kH parameters from start to end time of aging? If most of your pH and pK change is due aging then you have an acidic source in your tap water that is not fully dissolved when you initially test. In that case time for a ro or rodi filter. Alternatively if your aged water is essentially the same as what happens in your 70 gallon tank (which I doubt), you can live with that water unless your gH is very high, and use crushed coral. I disagree that CaCO3 will not affect kH if pH is not below 7. Also validate your system and get your water re-checked to ensure your pH and kH are what you think they are.

[brewmaster15]

Hello guys. I have a 75g tank with 7 discus. My question is I am having issue with my pH and kH.I cant figure out what making my pH/kH drop. My aged aerated tap water pH is 7.9 and kH 4. I did a 100% WC the day before I got my discus and the pH was 7.9 and kH of 4 but the next day my pH was 7.6 and kH 2. I noticed my pH/kH keeps dropping every day. I am doing 30% wc every other day but still pH/kH still dropping. Right now it is pH 7.3 and kH=1. I wonder what I need to do to stabilize my pH. I am thinking adding crushed corals in it and I want to know how to do it, if any of you have experience using crushed corals to stabilize pH please let me know how. Thanks

More water changes as Don suggested will stabilize the water . Crushed coral will too. I use it here alot. I would suggest using 1 cup crushed coral in a nylon stocking to start, this is placed in your canister filter. Over the next few days measure your pH and either add more or remove some until you get where you want it. You can also use oyster shells sold at chicken feed stores. There is another benefit to the crushed coral/shells. Young discus may grow better with the extra minerals in the water.

hth,
al

[Pjh4427]

Bottom line is that between the food and fish waste you are adding acidic compounds that are dropping your pH and kH together, adding a buffer is a short term fix at best with long term consequences as your cation (calcium in the case of coral) will constantly increase as you chase your pH. As an aside your fish also produce NH3 which is basic but is almost immediately converted to NO2 and then NO3 which is also acidic. Better to increase your water change volume to stabilize both pH and pK. Start at 50 % and see what your pH and kH are pre and post water change. Also, you indicated aged water, how long and what are the pH and kH parameters from start to end time of aging? If most of your pH and pK change is due aging then you have an acidic source in your tap water that is not fully dissolved when you initially test. In that case time for a ro or rodi filter. Alternatively if your aged water is essentially the same as what happens in your 70 gallon tank (which I doubt), you can live with that water unless your gH is very high, and use crushed coral. I disagree that CaCO3 will not affect kH if pH is not below 7. Also validate your system and get your water re-checked to ensure your pH and kH are what you think they are.

I am doing water change every other day so I guess my aging time is 24-48 hours. My water ph is 7.8 and kH=4 gh=6 straight from the tap after aging pH 7.9 KH=4. before water change My aquarium pH is 7.1 kH=1 or 0, after 30% WC my aquarium pH is 7.6 kH=3 but it will start dropping overnight. I only do 30% WC because I am afraid to do a large water change because of the huge difference from my aquarium pH and my aged water pH I am worried it might affect the discus. I am wondering because I have a 60g community tank that's been running for about 6 months now and that I rarely do wc but the pH is stable at 7.9. So I am really thinking there is something in my new tank that's affecting the pH.

[Pjh4427]

More water changes as Don suggested will stabilize the water . Crushed coral will too. I use it here alot. I would suggest using 1 cup crushed coral in a nylon stocking to start, this is placed in your canister filter. Over the next few days measure your pH and either add more or remove some until you get where you want it. You can also use oyster shells sold at chicken feed stores. There is another benefit to the crushed coral/shells. Young discus may grow better with the extra minerals in the water.

hth,
al

I did have 2 cups of crushed corals in media bag but I just placed it in the substrate. It has been a few days already, I did not notice any big change but it seems to hold the pH at 7.3. I was planning to add more but I guess putting it inside the filter will be more effective?

[brewmaster15]

I did have 2 cups of crushed corals in media bag but I just placed it in the substrate. It has been a few days already, I did not notice any big change but it seems to hold the pH at 7.3. I was planning to add more but I guess putting it inside the filter will be more effective?

Yes.. When the water flows through it the buffering is going to be greater.

[Pjh4427]

Yes.. When the water flows through it the buffering is going to be greater.

Ok I will try this method. Thanks