new cycling tank - low pH

[nano cool]

I 'm a newbie with salt water (I've been into freshwater planted tanks for quite sometime though). Luckily I came across these forums. They have been very helpful!

 

I setup a 12g JBL nano cube two days ago with 15 lb live rock, 4 lb aragonite sand, and DI water-Instant Ocean mix. The pH of my saltwater was 8.2 initially.

 

Within 12 hours of setting my tank up, the pH had dropped to 7.6. I then added Seachem Reef buffer to bring the pH to 8.4 (my dKH was raised from 5.56 to 12.3). The pH dropped to 8.2 about 12 hrs later, and now (approx 24 hr later) the pH has dropped to 7.8. Currently, my ammonia is about 0.25 and nitrites are measurable at 0.3-0.4.

 

My questions are:

 

1- Should I be striving to keep my tank's pH at 8.2-8.4 with the Reef buffer throughout the cycling process? I'm assuming that my low pH is being caused by die off of the live rock?

 

2- Why am I detecting nitrites so quickly after setting up the tank (i.e., less than 48 hrs)? I assumed that it would take several days for the bacteria to develop to siginificant levels in order to detect nitrites?

 

Thanks for all your help!

[lizbeth]

1. no

 

2. It depends what condition the live rock was in. And it depends on how you read the test results.

 

Just let the cycle happen.

[Tempest]

Do NOT add buffers during the cycle. The pH is probably dropping due to acidic products caused by the cycle (breakdown of dead matter). Once the cycle is over test the pH and for Magnesium, Calcium and Alkalinity - if these are in balance and your water is good (no ammonia, etc.) then the pH should level out to where you want it.

[nano cool]

Thanks for the advice. I have not added any additional reef buffer since. My pH has been fluctuating between 8.2 to 7.8. The total ammonia is about 0.25, and nitrites are about 30 ppm.

[koolyce]

Mmm....ok for the ph can be low if you ave all LR, but if you have like 2-3 pounds of LR and 15 pounds of base rock....how the ph can be low? Because water have amoniac and nitrite?

 

For cycling, I use a moly also.