why'd my pH sink?

[hc8719]

in my 20 gallon cycling tank, the pH randomly took a dive to 7.8

it has some LR, BR, and argonite sand (tiny CC). what could have caused the dive, the pH was at 8.1 about 2 weeks ago.

more importantly, how do i get it back up? i can add some CC i orginally took out and replaced (many weeks ago) but it shouldn't have dived like that, right?

 

[DragonForce]

PH swings between 7.8-8.1 are common IMO in smaller tanks. You can use a buffer to bring it back up. I like to use kent superbuffer-dKH. If you do not have a refugium your PH can swing at night time and go back up when the lights have been running for a while. Things do start to become more stable with time.

 

[hc8719]

thanks for the quick reply, so this is normal? though i dont have any fish yet, will this affect them?

i had just checked my pH a few minutes ago, and its just after 9PM in Ohio, so i guess that fits

 

[Sadielynn]

do you have a glass top if so that will cause your PH to drop but is normal to drop with lights out as well

 

[hc8719]

bare top tank, no glass or egg crate

 

[lando]

Ph will swing with the photo-period. It will increase with light and decrease with darkness. Try testing the same time a couple times a day (once at night when the lights have been on all day and once in the morning after the tank has been dark). As mentioned, surface agitation and gas exchange can make a difference. I would be reluctant to add a buffer to such a small amount of water volume. Surface agitation and regular PWC should keep buffering levels where they need to be.

 

[melosu58]

I would be reluctant to add a buffer to such a small amount of water volume. Surface agitation and regular PWC should keep buffering levels where they need to be.

I have to agree

 

[roka64]

I would try the natural way as well. As suggested, try to measure at the same time every day.

 

[tecwzrd]

Even if it does swing from 8.1 to 7.8 measuring at the same time each day it's not only normal for new tanks (less then 4 months) but also fairly harmless even if you did have fish. Fish/inverts can easily adjust to ph changes like that as long as it isn't sudden which more then likely isn't the case.

As Lando mentioned pwc will balance it out over time and adding buffers is only a short term fix which can be more harmful then helpful if overdosed.

 

[roka64]

I tried the buffer, but I could never get my pH stable. It just became a pain to add every day or so.

 

[Hara]

not to mention that it should still be cycling, during which time, ph is rarely stable.

 

[hc8719]

thanks