PH going higher than before CO2

Hi all, so I’ve seen this a few times with my tank where the starting pH is about 7.2 and then I add CO2 (and the pH drops to about 6.7, as expected) and then turn off CO2. Instead of the water going back to 7.2, it goes up to 7.7-7.8. It is GH 6, KH 6, pH 7.8 now. Is this common?

 

Hi all, so I’ve seen this a few times with my tank where the starting pH is about 7.2 and then I add CO2 (and the pH drops to about 6.7, as expected) and then turn off CO2. Instead of the water going back to 7.2, it goes up to 7.7-7.8. It is GH 6, KH 6, pH 7.8 now. Is this common?

CO2 off. Light still on, or light off at testing time?

 

CO2 off. Light still on, or light off at testing time?

Light turned off with CO2 turned off too at 2pm =6.7. Now it reads 7.8 at 8:45.

 

Hi all, so I’ve seen this a few times with my tank where the starting pH is about 7.2 and then I add CO2 (and the pH drops to about 6.7, as expected) and then turn off CO2. Instead of the water going back to 7.2, it goes up to 7.7-7.8. It is GH 6, KH 6, pH 7.8 now. Is this common?

Good Evening,
Is your tank heavy planted at all? Or do you have just a minimal amount of plants? Also, is there anything that could be leaching ions of carbon within your water column at night? How is your water change scheduled? Do you use liquid fertilizers? And do you run air stones at night when the lights are off?

 

Hi,
No

Good Evening,
Is your tank heavy planted at all? Or do you have just a minimal amount of plants? Also, is there anything that could be leaching ions of carbon within your water column at night? How is your water change scheduled? Do you use liquid fertilizers? And do you run air stones at night when the lights are off?

Weekly WC 20% Low to moderate amount of plants, no fish, no substrate. No air stone but have a sponge filter. I use Thrive C every 2 weeks. Had a short emergence of algae start to form but I used Tetra Algae Control and got it. It’s been happening on a few tanks since I started out and I don’t know what would leach carbon at night but I don’t think there is anything in the tank doing that. I use RO water (tests at 6.7, 1KH, 1 GH), condition it with Prime, then add equilibrium for GH, then alkaline buffer (just enough to raise the KH to 6, which only raises the ph to 7.2. It’s after CO2 injection that it bounces higher than the original pH, up to 7.7-7.8. Only possibility is that the alkaline buffer needs more time to fully raise the ph before adding CO2?

 

Did you account for evaporation? The KH buffer seems not to be used by plants or beneficial bacteria, so it could be accumulating in higher concentration. And yes, all KH, GH or pH changing products take a few hours to days to show the full level. They don't show instant changes of their full extent in the readings.

Also, why even use KH buffer? pH crashes are unbelievably rare and only happen under certain circumstances. (High animal stocking density and immense NO3 accumulation in low KH.) You're destabilizing the system by using several different products you don't even need.

Another no-need-product: You say you use RO water. As RO units have prefilters to prevent wear on the membrane, there should be no chlorine or chloramine in the water. Meaning if you use pure RO, you can also spare the Prime.

 

Did you account for evaporation? The KH buffer seems not to be used by plants or beneficial bacteria, so it could be accumulating in higher concentration. And yes, all KH, GH or pH changing products take a few hours to days to show the full level. They don't show instant changes of their full extent in the readings.

Yes I’ve accounted for evaporation and it’s happened multiple times, I’ll rule that out. So you’re saying it’s either the prime or the KH buffer and it may be due to not letting it sit out long enough. I’ll give it extra time, thanks!

 

Yes I’ve accounted for evaporation and it’s happened multiple times, I’ll rule that out. So you’re saying it’s either the prime or the KH buffer and it may be due to not letting it sit out long enough. I’ll give it extra time, thanks!

No, but if any, it's the KH buffer.
I just added, that you can leave out the Prime aswell.

You don't need either in my opinion.

 

Hi,
No

Weekly WC 20% Low to moderate amount of plants, no fish, no substrate. No air stone but have a sponge filter. I use Thrive C every 2 weeks. Had a short emergence of algae start to form but I used Tetra Algae Control and got it. It’s been happening on a few tanks since I started out and I don’t know what would leach carbon at night but I don’t think there is anything in the tank doing that. I use RO water (tests at 6.7, 1KH, 1 GH), condition it with Prime, then add equilibrium for GH, then alkaline buffer (just enough to raise the KH to 6, which only raises the ph to 7.2. It’s after CO2 injection that it bounces higher than the original pH, up to 7.7-7.8. Only possibility is that the alkaline buffer needs more time to fully raise the ph before adding CO2?

One thing affecting your water chemistry is definitely the amount of plants and you have the plants bare in the tank with no substrate? Furthermore, the combination of no substrate and no fish is not helping the process. Plants help with the buffering process, but the plants need minerals which are normally released by the substrate and assimilated by the plants through their roots. You have to keep in mind that “As plants photosynthesize, carbon dioxide levels in the water begin to drop and the amount of carbonic acid produced also falls. Thus, oxygen will also bind organics and minerals, and combined with falling carbonic acids, this causes pH LEVELS TO RISE.”

and you definitely have to add at least two air stones and have them on during the period of time when your lights are off in your tank. This will help the process explained above balance and become stable.

 

Thanks, Backblast, I will consider plant stocking, substrate and maybe just a few fish to help the plants along. This is just a storage tank for plants that I'm also using to run CO2 tests on before I buy fish, but I will spruce it up some to make the tests more worthwhile.

 

You can do a mixture of aqua soil or planting organic soil ( I used Miracle Grow’s Nature’s Own organic soil) for the lower level of the substrate. The volcanic rock is excellent media for beneficial bacteria and it acts as a natural buffer for water; it will have a tendency to naturally lower your pH. And you can cap these two lower levels with medium grade sand. Which will provide you with an excellent planting media; let alone how beautiful your tank will look with a sandy bottom and natural plants. Another benefit of using soil and volcanic rock is that it allows for even distribution of the water’s temperature and will allow the plants roots to spread and grow with no problem. Many of your plants will establish themselves very nicely within this planting material. Here is a picture of my tank and you can see the mixture of soil with sand . I allowed the soil to get mixed with the sand this way so that I could observed the roots of the plants as they grow. The other benefit of plants within a tank is that plants release allelow chemicals within the water column which act as natural buffers and maintain not only the plants healthy but also the fish. This natural balance takes about 60 days to get establish. Furthermore, plants are nature’s best filters, your tank will remain cleaner in the long run than without plants.

 

That's a great looking tank! If I decide to stop renting, I'm getting one of THOSE. Plants look terrific. My lease only allows 10 gallons. I'm using one for plant propagation/growth and on week 2 of DSM on the other - roots about 1 cm now Everybody on the forum was right when they said it is addictive and 'you will get a bigger tank'. Well I did, but it was up from 5 gallon so it wasn't hard to go to 10, lol.

I like the way the substrate made a pattern in the front glass, looks cool.

That's also some pretty clear water for having used Miracle-Gro, I've heard it really clouds the water but people love it in tanks- did you find that the sand on top limited this?

 

That's a great looking tank! If I decide to stop renting, I'm getting one of THOSE. Plants look terrific. My lease only allows 10 gallons. I'm using one for plant propagation/growth and on week 2 of DSM on the other - roots about 1 cm now Everybody on the forum was right when they said it is addictive and 'you will get a bigger tank'. Well I did, but it was up from 5 gallon so it wasn't hard to go to 10, lol.

I like the way the substrate made a pattern in the front glass, looks cool.

That's also some pretty clear water for having used Miracle-Gro, I've heard it really clouds the water but people love it in tanks- did you find that the sand on top limited this?

So as far as the organic soil (Miracle Grow) the first 3 to 4 days were the craziest while I was cycling the tank. I went with that soil because it had the lowest amount of ammonia which the soil will leach during the first 72-96 hours after exposure to water. The water will even have a strong ammonia smell to it and it will look milky. But after this occurs the smell goes away and the water becomes really clear. The plants live that stuff and have been growing healthy and lush ever since. You have to use the sand cap when you dirt the tank so that the soil does not get mixed with the water and turns your water to a dark muck which will look horrible. I layered my substrate. I used lava rock for the first layer, followed by the organic soil, and capped everything with a medium grade sand. Stay away from play sand. This type is way to find and light and will easily be picked up by your filters and ruin them in the long run.