pH Dropping During Cycling

[Juano908]

Just wonder why my tank pH is dropping from 7.97 to 7.56 in less than 24 hours.

Tank it’s been cycling fishless for almost 4 weeks, I added a raw shrimp and some Microbacter7 at the beginning, I tested the water for Ammonia and NO3 and they are both at 0ppm.
I’ve been ghost feeding some pellets once a week.

Thanks in advance for your input.

 

[Deep dive coral]

Do you have a skimmer running? And do you have power heads turning over the water and breaking the surface? Sounds like not enough gas exchange.

 

[RomoFL]

Have you had a lot of people come by within the 24hrs? Seems like maybe CO2 has increased?

 

[Mykawl]

I think that’s normal during the initial nitrogen cycle

 

[Juano908]

Do you have a skimmer running? And do you have power heads turning over the water and breaking the surface? Sounds like not enough gas exchange.

Yes to both, windows were open all day yesterday.

 

[Juano908]

Have you had a lot of people come by within the 24hrs? Seems like maybe CO2 has increased?

Not the case this time.

 

[Dal-Reef]

I think that’s normal during the initial nitrogen cycle

I would agree.. Part of the normal process. Now if it stays down for extend amount of time something else is going on. I am on the 3rd week of the cycle and last night added Fritz Turbo Start to finish out the cycle and my PH has dropped

 

[Mykawl]

Tried searching for an actual paper on the topic but can’t find it just remember reading something about the mass amounts of bacteria breeding during this process and consuming nutrients will effect pH.

 

[Mykawl]

Not sure why that screenshot is blurry but I think the answer is in that reply must be co2 related, bacteria consuming oxygen? Idk but I’m curious

 

[smartwater101]

Not sure why that screenshot is blurry

No worries, it's crisp when you click on it

 

[Deep dive coral]

I had an issue where my PH was high due to not enough CO2 in the system. I've lowered my turbulence on the surface and the PH has come down and normalized.

 

[Brew12]

Not the case this time.

Check your alkalinity. Some time alk will plummet in a new tank for one reason or another.

 

[RomoFL]

This is happening to me now but my pH is still good..

 

[Juano908]

Just got home and the pH is currently at 7.78
I’ll check the Alk just to see if it’s low.

 

[Juano908]

Alk is currently at 7.22, pretty sure it went down even tho I did not tested at the beginning, I’m using Brightwell NeoMarine Saltmix.

 

[Juano908]

Should I dose to bring the Alk up to 8.00 or just leave it?

 

[Deep dive coral]

No reason to dose. Do a small WC.

 

[Brew12]

Alk is currently at 7.22, pretty sure it went down even tho I did not tested at the beginning, I’m using Brightwell NeoMarine Saltmix.

That looks to be normal for the salt mix at 1.025 or just a little low for 1.026. I wouldn't do anything but wait. No reason to dose.

I suspect you are just at a point where you have more CO2 being created by the microbials in your tank than you have CO2 consumer and air exchange to remove them. A pH at 7.7 isn't bad during a cycle so I wouldn't worry about it too much.