Tap pH is 8 but tank was 7

I just tested my water and my tap waters ph is 8 but my tank's ph was 6.8 to 7. I'm really confused because my water is hard with gh of 10 and kh of 7 yet my ph fluctuates so much and kh is eaten away. I did a 50% water change and ph is 7.6-7.8 now. Anyone know why my ph was this low?

 

Do you have driftwood? The tannins in the wood can lower ph if it is leaching (turning the water yellowish).

 

Nope. Just live plants.

 

Do you inject CO2? Carbon dioxide will also lower ph

 

No it's a low tech moderate lighting and I use root tabs for my heavy root feeders and easy green all in one liquid fertilizer weekly.

 

Have you tried filling up a bucket with tap water and checking the ph after it sat for 24hrs(with an airstone if possible)? Usually the opposite of your situation is the result(ph rise instead of drop) but there is some water facilities that have treatments that actually remove most of the co2 from the water.once the water is out of the tap the ph will drop as the co2 gets back in to it.Its worth a shot

 

Have you tried filling up a bucket with tap water and checking the ph after it sat for 24hrs(with an airstone if possible)? Usually the opposite of your situation is the result(ph rise instead of drop) but there is some water facilities that have treatments that actually remove most of the co2 from the water.once the water is out of the tap the ph will drop as the co2 gets back in to it.Its worth a shot

 

Sorry I accidentally sent that reply. Yeah my tap ph is 7.2 then after 24 hours its 8 so I just assume it will turn to 8 after 24 hours in the tank right?

 

Sorry I accidentally sent that reply. Yeah my tap ph is 7.2 then after 24 hours its 8 so I just assume it will turn to 8 after 24 hours in the tank right?

Yeah most likely.The rise in ph is what most people deal with but I figured it was worth a shot as some people have a drop.I dont use tap water now but when I did it was nearly identical to yours but with around 7.6ph.i switched to ro water because it was solid as a rock and I could barely get the ph .1 lower with driftwood and catapa leaves and tannins galore.If your water parameters(nitrite ammonia nitrites) are staying good then you you can add crushed coral to your tank.It dissolves at a faster rate as your ph drops and buffs your water to around a 7.6ish ph.1lb of coral per 10 gallons does the trick and you can just add more as it dissolves away.Doesnt really answer the question you have about what exactally is eating your kh in between water changes but it's a great fail safe to use if you are happy to have a stable higher ph

 

Yeah most likely.The rise in ph is what most people deal with but I figured it was worth a shot as some people have a drop.I dont use tap water now but when I did it was nearly identical to yours but with around 7.6ph.i switched to ro water because it was solid as a rock and I could barely get the ph .1 lower with driftwood and catapa leaves and tannins galore.If your water parameters(nitrite ammonia nitrites) are staying good then you you can add crushed coral to your tank.It dissolves at a faster rate as your ph drops and buffs your water to around a 7.6ish ph.1lb of coral per 10 gallons does the trick and you can just add more as it dissolves away.Doesnt really answer the question you have about what exactally is eating your kh in between water changes but it's a great fail safe to use if you are happy to have a stable higher ph

Yeah idk why for a good 2 weeks it was at a stable 8. Maybe because the tank is still cycling is why? Thanks for the coral tip might look into it.

 

Yeah most likely.The rise in ph is what most people deal with but I figured it was worth a shot as some people have a drop.I dont use tap water now but when I did it was nearly identical to yours but with around 7.6ph.i switched to ro water because it was solid as a rock and I could barely get the ph .1 lower with driftwood and catapa leaves and tannins galore.If your water parameters(nitrite ammonia nitrites) are staying good then you you can add crushed coral to your tank.It dissolves at a faster rate as your ph drops and buffs your water to around a 7.6ish ph.1lb of coral per 10 gallons does the trick and you can just add more as it dissolves away.Doesnt really answer the question you have about what exactally is eating your kh in between water changes but it's a great fail safe to use if you are happy to have a stable higher ph

So I could fill a bucket with tap water a couple days before the water change and the ph would be 8 by the time the water change. Would that work?

 

What substrate do you use?

 

What substrate do you use?

caribsea eco complete

 

Whoops, let's get this straight,

Your tap water is 7.2 and tank water is 8.0?

 

Whoops, let's get this straight,

Your tap water is 7.2 and tank water is 8.0?

Tap water at first comes out at 7-7.6 range and after 24 hours the ph of it is 8. My tank water currently is 7.8-8 because I did a water change around 24 hours ago so the ph of the water I added went back to 8.

 

Tap water at first comes out at 7-7.6 range and after 24 hours the ph of it is 8. My tank water currently is 7.8-8 because I did a water change around 24 hours ago so the ph of the water I added went back to 8.

Okay that is normal as the CO2 off-gasses, the carboxylic acid levels reduce allowing the pH to climb to its true value. Nothing to worry about.

 

Okay that is normal as the CO2 off-gasses, the carboxylic acid levels reduce allowing the pH to climb to its true value. Nothing to worry about.

Does the ph change cause stress in the fish or does it affect them?

 

Does the ph change cause stress in the fish or does it affect them?

No, because there is no mineral / TDS change and no osmotic pressure change. It's simply a very weak acid dropping the pH, and then slowly raising it as the CO2 offgasses and carboxylic acid concentrations reduce.

 

No, because there is no mineral / TDS change and no osmotic pressure change. It's simply a very weak acid dropping the pH, and then slowly raising it as the CO2 offgasses and carboxylic acid concentrations reduce.

Thank you. Funny how we become almost like chemists when keeping fish.

 

I just tested my water and my tap waters ph is 8 but my tank's ph was 6.8 to 7. I'm really confused because my water is hard with gh of 10 and kh of 7 yet my ph fluctuates so much and kh is eaten away. I did a 50% water change and ph is 7.6-7.8 now. Anyone know why my ph was this low?

Idk if there is a proper way to do an update but I'm just gonna do it like this. After recent testing I have found that my tap water ph is 7.8 straight out of the tap. This is weird because it use to be lower but it might be because I couldnt read the test right since that was around a month ago. Kh is 6 and gh is 8. Now this is before 24 hours so I'll leave the water out to test in 24 hours. My tank water is ph is 7-7.2! I'm really confused why its so low because I have nothing that could be lowering the ph in the tank. Gh is 8 and kh is 4-5. Something might be eating away my kh but idk what. I did a 40% water change 3 days ago. If anyone can help it would be appreciated.

 

The organics in your substrate are buffering your water's pH.

 

The organics in your substrate are buffering your water's pH.

Wdym by this? Eco complete doesnt contain a buffer.

 

It isn't unheard of for the PH to drop during the cycling process. Lots of changes are going on during this time. I think someone already suggested adding crushed coral to help stabilize your PH up to the same level as your source water. I both use and recommend using it.

 

But isn't the whole point of crushed coral to raise kh? My tap waters kh is 6-7 surely that's a good enough buffer.

 

But isn't the whole point of crushed coral to raise kh? My tap waters kh is 6-7 surely that's a good enough buffer.

As far as I can tell the crushed coral doesn't raise my KH any measurable amount but it does stabilize my PH. Apparantly it isn't enough to buffer it if it is dropping this low once in the tank.

 

CC raises kH, that's the whole point of using it. A raise in kH from CC inevitably results in a raise in pH.


OP, how are you tesing pH?

 

CC raises kH, that's the whole point of using it. A raise in kH from CC inevitably results in a raise in pH.


OP, how are you tesing pH?

Do you see that as a good thing or something one should avoid? Are you saying CC shouldn't be used in this case? As I said, the CC doesn't raise mine any measurable amount but in my case my tap water is almost devoid of minerals. It actually has a TDS reading of 16 right now. It was 21 before we went about a month of daily rain. I thought my GH/KH testing solution had gone bad because I could not get a reading for either.

I feel sure you know more of the science behind what is happening. I only know that CC will raise and stabilize ones PH and is a simple solution.

 

Do you see that as a good thing or something one should avoid? Are you saying CC shouldn't be used in this case? As I said, the CC doesn't raise mine any measurable amount but in my case my tap water is almost devoid of minerals. It actually has a TDS reading of 16 right now. It was 21 before we went about a month of daily rain. I thought my GH/KH testing solution had gone bad because I could not get a reading for either.

I feel sure you know more of the science behind what is happening. I only know that CC will raise and stabilize ones PH and is a simple solution.

Simple yes.

It stabilizes the pH because it raises kH. kH is the buffering ability of the water to resist changes in pH. Your situation is unique because your water is so low in conductivity.

A kH as low as 0.5 or 1.0 is enough to avoid a tanks ability to swing pH. Acids produced organically through various nutrients cycles aren't strong enough to eat away all the buffering ability, even at low levels like a kH of 0.5. This is especially true when regular water changes are performed, which constantly top-off any reduction in kH that may be happening.

A simple and roe controllable way to adjust your water, would be to remineralize to a kH of 1 degree and a gH of 6-8 8.

This is done with 3 products, simply change the same amount of water with every water change, and dose these minerals in the same quantities into the new water at each water change.

Use KHCO3 for kH - aim for 1.0
Use CaSO4 for Ca (gH) - aim for 30ppm (5 ish degrees of gH)
Use MgSO4 for Mg (gH) - aim for 10-15ppm (2 ish degrees of gH)

This will result in water that is ~7.1 in pH, low TDS, and is nice and soft for the majority of common freshwater fish (African Cichlids and some Livebearers excluded). These levels are also a very good base for plants, for Neo shrimp.

 

CC raises kH, that's the whole point of using it. A raise in kH from CC inevitably results in a raise in pH.


OP, how are you tesing pH?

I'm using api master test kit.

 

I'm using api master test kit.

It's not the most accurate test but... it's a good ball park test for pH.

Could you restate your values? :

Straight tap pH?
Degassed tap ph?
Degassed tap kH?
Tank water pH?
Tank water kH?

TDS of tapwater?
TDS of tankwater?

What rocks / hardscape do you have in the tank?
What chemicals / treatments are you dosing?
What kind of tank is this?
Do you top - off the tank with tapwater?
Do you have access to a water report?

 

It's not the most accurate test but... it's a good ball park test for pH.

Could you restate your values? :

Straight tap pH?
Degassed tap ph?
Degassed tap kH?
Tank water pH?
Tank water kH?

TDS of tapwater?
TDS of tankwater?

What rocks / hardscape do you have in the tank?
What chemicals / treatments are you dosing?
What kind of tank is this?
Do you top - off the tank with tapwater?
Do you have access to a water report?

Tap water (straight out): 5 kh, 7.8-8 ph
Tap water (after 24 hours): 5 kh 7.8-8 ph.
Tank water: 2-3 kh, 6.8-7.0 ph.
I didnt know my tap water DIDNT increase after 24 hours because I swear when I tested the water before I setup the tank i got 7.4-7.6 ph straight out of tap. Maybe I was just reading the test wrong then?

I dont know TDS because I dont have a tds pen or whatever.

No hardscape atm just plants.

29 gallon aqueon tank.

I dont top off.

I just use prime every 24 hours to detoxify ammonia as the tank is basically cycled just been stuck with 0.25ppm ammonia for about 4 days now.

The water report says that for my county water hardness (dont know If it means gh or kh) is above 10.5 mg/l.

My main problem is why the tank's ph and kh is so low. My kh in the tank just yesterday was around 4.

 

I'm wondering if dosing Prime every day is causing some issues,...

 

I'm wondering if dosing Prime every day is causing some issues,...

It says on the bottle that it wont alter ph but who knows.

 

Wdym by this? Eco complete doesnt contain a buffer.

Until you do 5-6 big water changes in the first month or so it messes with your water parameters. After that it doesn't.

 

Until you do 5-6 big water changes in the first month or so it messes with your water parameters. After that it doesn't.

It said on the bag that it wouldn't alter tank ph, that's the whole reason I got it because my tap water is basically perfect for guppies.

 

Until you do 5-6 big water changes in the first month or so it messes with your water parameters. After that it doesn't.

And also if anything I've heard that eco complete raises ph not lowers it.

 

And also if anything I've heard that eco complete raises ph not lowers it.

Another update. I may know the reason. Do API root tabs have any effect on ph? As mentioned I have decently hard water with a kh of 5-6. I have a total of 3 root tabs buried decently deep. This doesnt make since as I cant see 3 root tabs lowering the ph form 7.8-8 all the way to 6.8-7.

 

Another update. I may know the reason. Do API root tabs have any effect on ph? As mentioned I have decently hard water with a kh of 5-6. I have a total of 3 root tabs buried decently deep. This doesnt make since as I cant see 3 root tabs lowering the ph form 7.8-8 all the way to 6.8-7.

No the tabs wont do anything to pH

I'm wondering if your water is treated differently than the majority of us.

Are you using the high or low range pH test consistently every time?

 

No the tabs wont do anything to pH

I'm wondering if your water is treated differently than the majority of us.

Are you using the high or low range pH test consistently every time?

Yes I use both every time I test. I did a 20% water change and it raided the ph to around 7.4. Hopefully I can slowly raise the ph back up with water changes.

 

What all is in the tanks full system?

Decor, plants, substrate, filter media anything else? Could you let us know what is exactly in the tank?