# pH swing - does is matter?



## sfsamm (Apr 3, 2017)

Does this swing happen every day exactly the same or does it vary?
I ask as if your tank is very heavily planted it may be the cause. Plants are actually putting our some co2 at night rather than o2, in doing so with your kH at zero I imagine that it "could" be a drop from just co2 and it rises during your photoperiod because the plants again are sucking up the co2 and putting off o2.

If that's the sole cause of the swing it should not affect your stock. I don't keep CRS, I'm not patient, dedicated nor rich enough to change my liquid rock 8.2 water for them. I know that they can be really really finicky so maybe it does affect them. I did though think most varieties preferred a kH around 1-2... If yours are able to accept that it would lessen the swing your seeing and maybe help get shrimplets raised up.

Just my $.02

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## mheat (Apr 24, 2013)

Yes, the pH swing happens everyday within the photo-period. I know when plants release Oxygen during the day, it causes the pH to rise. It release CO2 during night and pH will drop. It happen naturally. Do I really need to increase the KH to 1-2? If I raise the KH, the pH will increases too.


This is the picture of my tank. It is a 5 gal tank only.









The pH swing is pretty high from 7.0 to 7.6, but it change slowly, and it should not consider as a pH shock.

I read many discussion about pH swing. Is it really that pH shock is a myth? I know it has minimum effect on fish, but shrimps are lower level, and it can be more sensitive to pH change, especially the CRS.


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## Zoidburg (Mar 8, 2016)

Your main issue could be due to the fact that you aren't using a buffering substrate to keep your pH below 7 where Caridina's, such as Crystals, would thrive in.

If you don't want to rescape the tank with a buffering substrate (one that doesn't leach ammonia, or is no longer leaching ammonia), then you may want to consider adding in containers of buffering substrate that could help lower the pH or even consider setting up a HOB or even a pump powered breeder box to circulate water over the buffering substrate.



Another thing to consider is diet... is there enough biofilm or food for the babies to eat?


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## Surf (Jun 13, 2017)

I had a big shift occur after installing a new light. MY PH was approaching 9 before the lights turned off. I solved the issue by dimming the light. Now my PH is stable at 7.


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## mheat (Apr 24, 2013)

6 months ago, same water condition, same lighting, my CRS shrimplets could survive about 80% and grow up to adult shrimps. Recently, the female shrimps still get berried, but shrimplets can't pass 3 weeks. Only a few can grow up, most of them disappeared (die). I tested the water, and can't see anything wrong. I am still look for answers.


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## Surf (Jun 13, 2017)

Try adding a fertilizer. Shrimp have many of the same nutrient needs as plants with some differences. But if you are using RO water and no fertilizers. The Salty Shrimp doesn't have all the nutrients needed. YOU plants have probably depleted the water of many trace nutrients. Your plant are probably struggling to get get what they need. Leaving little to nothing for the shrimp lets.

For example lets look at copper. Plants cannot grow without it and there will be very little in RO water. Shrimp also need it in there blood. People have iron based blood. However shrimp have copper based blood. The adult shrimp might have enough copper but the rapidly growing shrimp lets might not be getting enough. 

Try adding a trace and macro fertilizer. such as Nilocg. I don't know if it will work but it will make the water much closer to what is in naturally occurring soft water.

Liquid NPK+M 500ml | Premium Liquid Fertilizer | NilocG Aquatics


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## Deanna (Feb 15, 2017)

Your water has no buffering capacity (KH=0), so ph will move dramatically with slight changes in CO2. You should hold KH at least in the 2-3 degree region. Most go higher (4-5). This will prevent wild pH swings. I don't see your tank size, but add about 5 grams (1 teaspoon) of baking soda (not baking powder) per 30 gallons of water to move your KH by about 2 degrees. GH has nothing to do with pH, but will show up in TDS.

pH swings, especially as mild as yours (7-7.6) are not bad. TDS swings are far more impactful. They should not be moved by more than about 10% at once. Have you measured those swings when you measure pH? I think you will find they don't move at all when your pH is moving.


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## mheat (Apr 24, 2013)

I spoke to a few shrimp breeders, their KH is 0 as long as it is a low tech non CO2 tank. I used to add Carbonate to the tank to make KH=2, but at the same time the pH will also increase from 7.0 to 7.5. If I make it KH=4, the pH goes up to 7.8 immediately.

My TDS is very stable at around 150.


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## Deanna (Feb 15, 2017)

mheat said:


> I spoke to a few shrimp breeders, their KH is 0 as long as it is a low tech non CO2 tank. I used to add Carbonate to the tank to make KH=2, but at the same time the pH will also increase from 7.0 to 7.5. If I make it KH=4, the pH goes up to 7.8 immediately.
> 
> My TDS is very stable at around 150.


I understand, but then you should expect the fluctuations you are seeing without the buffering, and they don't seem that high to me. I suppose that, if you want to truly establish a stable pH level, you could buffer to 4-5 dKH, then add CO2 until your target is reached.

However, this may not be addressing your shrimp issue. Been many years since I played with shrimp breeding and i only keep Amanos in my community tank now.


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## Surf (Jun 13, 2017)

> Your water has no buffering capacity (KH=0), so ph will move dramatically with slight changes in CO2. You should hold KH at least in the 2-3 degree region. Most go higher (4-5). This will prevent wild pH swings.


Increasing KH will have no effect on the PH swing. Carbonate do nothing in the aquarium other than neutralizing acids in the water. So If your PH is 7 the increased KH will not prevent it from going up. However if the PH drops due to too much acid in the tank the carbonates will neutralize the acids and push the pH back to 7. But they will not push thePH higher than 7.


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## Zoidburg (Mar 8, 2016)

The higher the KH, the higher the pH is likely to be..... so with a KH of 2-3, the pH may be more stable between 7.2 to 7.6... that is, the pH shouldn't drop *as much*.


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## Deanna (Feb 15, 2017)

Surf said:


> Increasing KH will have no effect on the PH swing. Carbonate do nothing in the aquarium other than neutralizing acids in the water. So If your PH is 7 the increased KH will not prevent it from going up. However if the PH drops due to too much acid in the tank the carbonates will neutralize the acids and push the pH back to 7. But they will not push thePH higher than 7.


Didn't we just say the same thing?


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## mheat (Apr 24, 2013)

Again, I don't have CO2 injection. It just the process of photosynthesis. When light on, plant absorb carbon dioxide and release oxygen, pH goes up. When light off, plant absorb oxygen and release carbon dioxide, pH goes down. It is all natural. Some people said increase buffer to KH=4, and some said no need. Who is correct?

If I raise the kH to 4, pH will goes up to 7.8 or above. That is no good to CRS shrimp in such high pH environment.


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## Deanna (Feb 15, 2017)

mheat said:


> Again, I don't have CO2 injection. It just the process of photosynthesis. When light on, plant absorb carbon dioxide and release oxygen, pH goes up. When light off, plant absorb oxygen and release carbon dioxide, pH goes down. It is all natural. Some people said increase buffer to KH=4, and some said no need. Who is correct?
> 
> If I raise the kH to 4, pH will goes up to 7.8 or above. That is no good to CRS shrimp in such high pH environment.


It comes down to what you want. If you bring KH up to 4, it will raise pH, but it will also keep the pH from moving as much as it does now.

If you want pH as low as can be, without injecting CO2, keep KH as low as you can, but expect higher variability. You can try to push pH down with driftwood, catappa (Indian Almond) leaves, etc. but a good effort by those things will release tannins (which are what makes it acidic) that can make your water look like tea (in fact, some people use tea to do it). If you use those, check to make sure that your chemical media (such as Purigen) are removed if they are known to absorb tannins.

Also, try to keep the water surface still, so that CO2 exchange is minimized.


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## Surf (Jun 13, 2017)

> Again, I don't have CO2 injection. It just the process of photosynthesis. When light on, plant absorb carbon dioxide and release oxygen, pH goes up. When light off, plant absorb oxygen and release carbon dioxide, pH goes down. It is all natural. Some people said increase buffer to KH=4, and some said no need. Who is correct?
> 
> If I raise the kH to 4, pH will goes up to 7.8 or above. That is no good to CRS shrimp in such high pH


If you don't want to increase your PH then you cannot add any KH. Then you must look for another solution. On the 10/28 I mentioned I had the same problem but I had much bigger PH swings. I simply eliminated the problem by dimming the lights. This slowed plant growth somewhat but the PH stayed stable at 7.0. This worked by reducing the consumption rate of CO2 which allowed more time for the water to absorb CO2 from the air. Increasing aeration of the water may also help keep CO2 and oxygen levels stable. 

My tank is filled with RO water and I have calcium carbonate (old snail shells in the water) This keeps my PH at 7 and the KH is about 2 degrees. For Aeration my filter output spray bar is located about 1 inch above the water surface. As the water fall and hits the surface this drags air bubbles below the surface aerating the water. At the time I had My PH swings This was how my tank was set up. And As I said I simply dimmed the light and the PH immediately stabilized at 7.0. 

Dimming the lights puts the CO2 addition from the air in balance with the CO2 consumed by the plants. This results in stable CO2 levels and a stable PH.




> Also, try to keep the water surface still, so that CO2 exchange is minimized.


This is not good advise. CO2 makes the water acidic so if you want lower PH you need to gas as much as possible in the water through Aeration or through CO2 injection. If you reduce aeration CO2 will fall faster with lights on and oxygen levels will be reduced which is not good for shrimp or fish. Reducing aeration would work if you have CO2 injection since it would reduce the CO2 loss to to the air allowing more of the CO2 injected to stay in the water and PH to stay lower. Since CO2 system is not what you want you have to get CO2 form the only source available the air. So you have increase the aeration to get more of the CO2 in the air into the tank.


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## dukydaf (Dec 27, 2004)

Surf said:


> Shrimp have many of the same nutrient needs as plants with some differences.


This made my day:laugh2::laugh2::laugh2::laugh2: 



mheat said:


> *Temperature: 74F
> Water Type: R/O water
> PH: 7.0 - 7.6
> GH: 5
> ...


Hi mheat, 

as you point out this is pH bounce is natural and normal. Does it matter?, my intuition says no, but I do not have the time to experiment and prove it. So, let us assume that we would like to keep the pH as stable as possible. 

As most pointed out a KH of ~0 will have no alkalinity, so no acid buffering capacity. However pH is determined by too many things besides KH. When you expose pure H2O to the atmosphere the water will not have a pH of 7 but of about 5.5. This is because CO2 will get dissolved in the pure H2O, forming carbonic acid until there is equilibrium with the atmospheric CO2 according to Henry's Law and so on... So something is driving your pH up. This is why buffering substrates are so great for CRS. Although risky you can drive the pH down with peat, though dose in minute amounts. Maybe a KH of 1 would not harm your shrimp but hey I am no shrimp expert here. 

If you increase aeration and water surface movement your pH will not be influenced by respiration and photosynthesis. During the day, you will introduce CO2 and push out the O2 until you are at equilibrium with the atmosphere. During the night you will introduce O2 and push out CO2 until you are at equilibrium with the atmosphere. So if you have enough aeration your O2, CO2 will always be at equilibrium with the atmosphere.

For the GH, KH you have the TDS looks rather large. Maybe a water change should be done to reduce the other stuff floating around. 

All the best to you and those quite baby shrimplets.


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## Deanna (Feb 15, 2017)

Surf said:


> This is not good advise. CO2 makes the water acidic so if you want lower PH you need to gas as much as possible in the water through Aeration or through CO2 injection. If you reduce aeration CO2 will fall faster with lights on and oxygen levels will be reduced which is not good for shrimp or fish. Reducing aeration would work if you have CO2 injection since it would reduce the CO2 loss to to the air allowing more of the CO2 injected to stay in the water and PH to stay lower. Since CO2 system is not what you want you have to get CO2 form the only source available the air. So you have increase the aeration to get more of the CO2 in the air into the tank.


I disagree. CO2 readily dissolves in water, quickly replacing any that is consumed. By rippling the surface, the most you can obtain is about 1-2 ppm of CO2 in the water from atmospheric CO2. If decomposition is generating any additional CO2, you will lose that added CO2 with surface agitation.


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## clownplanted (Mar 3, 2017)

Surf said:


> If you don't want to increase your PH then you cannot add any KH. Then you must look for another solution. On the 10/28 I mentioned I had the same problem but I had much bigger PH swings. I simply eliminated the problem by dimming the lights. This slowed plant growth somewhat but the PH stayed stable at 7.0. This worked by reducing the consumption rate of CO2 which allowed more time for the water to absorb CO2 from the air. Increasing aeration of the water may also help keep CO2 and oxygen levels stable.
> 
> 
> 
> ...



Sorry but no. Not true at all. By increasing aeration you are forcing out what little co2 is in the water(low tech so 3ppm max) and reducing that even more. You can test this if you wish. 


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## mheat (Apr 24, 2013)

A lot of different opinions here. Not sure which one is right. One thing I am sure that if I raise the KH to 4 (using carbonate), the PH will up from 7 to 8. PH will be pretty much stable at 8 day and night if KH is constantly at 4. But PH 8 is not preferable for crystal shrimps.


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## arcticwolf (Mar 12, 2014)

another thing to consider ... are the shrimp getting enough to eat
Many threads on here claim adding bacteria additives or baby food really helps shrimplet survival ... i had issues with many baby's disapering until i started adding a baby food twice a week and bacter ae once a week ... now i got an ocean of shrimp in the tank


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## natemcnutty (May 26, 2016)

I have CRS that I keep between 7.4-7.6 with a KH between 2-3, and during CO2 intention, it drops to 6.8ish and then back up. The temps also roam from around 69 up to 73 and back down every day. Over two years in on this tank without issues related to pH or temp swings. Just tossing that it there as a data point.

My opinion, don't worry about the pH swing. Just make sure they have good minerals, enough food, and they'll take care of themselves 

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