Ph Dropping

[Spooky76]

Hiya,

I recently put some C02 into my tank, using the small cannister and yeast, sugar and bicarb, all seemed to be going well. It was only rated for a 70l tank so figured with mine being a 125l I would be OK.

MY friend suggested I watch my PH, so I have started to test it as soon as I get home. I checked last night and it has dropped from about 6.8 to about 5.5.

I am worried that I should be adding something else to stabalise the PH. So really my question is should I be doing something else ? Or should I stop C02 ASAP ?

Any helps appreciated - I am very new to the whole c02 thing

Thanks

 

[Themuleous]

Whats your kh? A 30ppm level of co2 should only reduce the pH by 1 point, i.e, from say 6.6 to 5.6. Yours has dropped 1.3. Either the test kit is wrong or have no KH left. I suspect the test kit.

Sam

 

[Colin_T]

probably not enough plants for the CO2 going in and not enough carbonate hardness (KH) to stabilise the PH.
A piece of limestone would help but better off adding some KH buffer and getting that up.

 

[Spooky76]

Hey guys - there are lots of plants in the tank, around 20 I think...
Its a digital PH tester and works fine in my other tank, so I had no reason to think it was wrong.
I will take some Kh tests tonight.
Can you but Kh buffer off the shelf ?

 

[Colin_T]

should be able to but I can't think of what they used to use. I think it was calcium carbonate (chalk) and you put some in a container of water and shake hell out of it. Then after a while the chalk settles to the bottom and you use a small amount of the clean water above it. Don't quote me on that tho coz it's been a long time.

 

[Spooky76]

Hiya -just got home and tested PH... With digital meter, liquid and strips, its about 5.5 - 5.9 all 3 say the same thing.

Kh is worryingly low though, around 4-5 so I have stopped the c02 until I can stabilise my PH / Kh levels.

I will do some research see what I can add to increase my Kh value and then try again.

Luckily all the fish are OK and seem fine still.

gutted

 

[SuperColey1]

probably not enough plants for the CO2 going in and not enough carbonate hardness (KH) to stabilise the PH.
A piece of limestone would help but better off adding some KH buffer and getting that up.

Doesn't matter how many plants you have. If there are none and you are running 30ppm it is the same as if you have a jungle with 30ppm.

30ppm is the concentration in the water and not how much you are injecting so no matter if you have no plants or loads of them Co2 with a standard KH will only reduce the Ph by 1ish.

Therefore must be KH that is the cause of the crash.

Andy

 

[Spooky76]

Hi Andy - thanks for the info.

I will TRY to get something to add some buffer to my tank. My tap water Ph and Kh are higher than my tank, so I will start doing 10% water changes to try to get my Ph back to around 6.5 before I start anything again also my Kh usually is about 9 so I need to get that back up again.

Will it crash again as soon as I start C02 ? Do I need it alot higher before I start again ?

 

[Themuleous]

Just to reassure you, a KH of 4 to 5 is perfect and will NOT result in a pH crash if it stays at these levels. My tanks run at around 1dKH!!! With no problems.

However, if the KH has dropped recently then that could explain the pH drop. My first guess would be wood, do you have any in the tank? Some types of wood will remove KH from the water.

BTW I would start the CO2 again, providing the KH doesn't drop below 1KH then the pH will NOT swing dramatically. Its old school to think 4KH or lower causes a crash, it doesn't.

I would monitor the KH and pH for the next few days to see if there is a trend. Personally I dont like adding anything more than I have to, to my tanks so I wouldn't advise adding more KH to bring the pH up. That in itself could cause the pH to rise dramatically and damage your fish. Lets get to the root of the problem and fix that first

Sam

 

[Dave Spencer]

Luckily all the fish are OK and seem fine still.

Spooky,

I have a tank with around 1 - 2dKH, a pH around 6, CO2 at around 30ppm and lots of wood in there. Here`s what I do.......

......I sat back, have a beer and enjoy watching my healthy plants and fish. Oh, and I never bother testing.

Dave.