Raising low pH

[Su James]

Hi,

We've got a 50 gallon well planted tank on the go at the moment. I'm hoping to add co2 to it soon but have an issue. The pH is about 6.5 and as I understand it will get even lower when I add co2. I don't want the pH too low as it'll upset the snails...

Apart from plants there is a "clay" gravel and some slate as scaping. I've come to the conclusion that the slate is reducing the pH. Would anyone else agree? I popped some slate in a jar of tap water and tested the pH a few days later and it was very low. I was surprised as I'd assumed slate was inert.

The tank looks pretty good and I'm really loath to take out all the slate so I was looking for advice as to how to raise the pH. At the moment there is a net bag of shell chips in the filter which has made no impact.

Cheers,
Su

 

[Tim Harrison]

I doubt it very much it's usually fairly inert, that's why it's used in construction. If anything it would probably increase pH. It's metamorphosed shale - a mixture of clay, silt, and other minerals such as calcite.
I don't think you need worry either way. Have a read of this and the links within...http://www.ukaps.org/forum/threads/co2-injection-leading-to-large-decrease-in-ph.23327/#post-239549

 

[RossMartin]

I thought the issue with a PH that is changing is what is changing it. For example injecting CO2 isn't the same as having some hardscape that is doing it.....i could well be wrong but i'm sure one of the clever guys will correct me!

 

[Julian]

I thought the issue with a PH that is changing is what is changing it. For example injecting CO2 isn't the same as having some hardscape that is doing it.....i could well be wrong but i'm sure one of the clever guys will correct me!

pH is pH regardless of what is changing it. I think your talking about the reaction that occurs inside a drop checker if tank water is used instead of 4dkh water.

 

[RossMartin]

No, i read somewhere that a PH drop caused by adding CO2 isn't as serious as a PH drop caused by some hardscape for example. I can' remember where i read it though. I'm sure is was something by Ceg.

 

[ian_m]

No, i read somewhere that a PH drop caused by adding CO2 isn't as serious as a PH drop caused by some hardscape for example. I can' remember where i read it though. I'm sure is was something by Ceg.

pH down is caused by the weak acid carbonic acid produced by carbon dioxide and the pH up from hardscape is the weak bicarbonate usually from calcium carbonate. As both are weak they have virtually no effect on fish or plants who generally don't care about pH values.

 

[Julian]

pH down is caused by the weak acid carbonic acid produced by carbon dioxide and the pH up from hardscape is the weak bicarbonate usually from calcium carbonate. As both are weak they have virtually no effect on fish or plants who generally don't care about pH values.

Is it safe to say that most hardscape does not cause pH to drop, only increase? Are there any that might make it drop?

 

[ian_m]

Are there any that might make it drop?

Usually organic based "things" leaking organic acids, peat, drift wood and even dead fish.

 

[dw1305]

Hi all,

The pH is about 6.5 and as I understand it will get even lower when I add co2. I don't want the pH too low as it'll upset the snails...

I think your pH will upset your snails long term whatever happens.

There are details in the linked thread, but when you add CO2 you are altering the CO2 ~ HCO3 equilibrium, which isn't the same as changing the water chemistry.

Have a look at <"pH drop and high ..."> & <"Nerite Snail in high tech">.

cheers Darrel

 

[RossMartin]

Cheers Darrel,

That was the link i was thinking of, i perhaps didn't explain myself very well....in my defense i just got off the plane after getting back from Mexico!

 

[Su James]

Thanks guys. I'll have a read through and get my head around it.