pH and cycling

[krow]

I am cycling my new 55 gal. and I noticed my pH has dropped from 8.2 to 7.8 over a period of 6 days. From what I gathered, the pH usually rises. I was wondering if it dropping like that is normal?
Also I am curing my lr in the tank and was wondering if i should scrub off the white decaying sponges ( I'm guessing that is what they are).

 

[beefcake]

I had the same thing happen to me. Tested my water on 1/23/03 and ph was 8.6. Retested 5 days later and ph is now 7.7 .

 

[yetex]

If it was me i wouldn't worry about the sponge, I had some sponges decay during my cycle and the cycle completed in 16 days

 

[barracuda]

It does matter at what time of the day you chech your PH. Usually PH is at its highest levels during the daylight and low during the night time, especially second half of the night. PH swing is always possible from 7.8 to 8.4 . But 7.8 during the day is kind a low.
There is another mesurment which is not less imporatant called Alkalinity. Alkalinity is a measurment of buffer capacity of the sea water and responsible for PH stability. When adjusting PH, Alk should also be adjusted and brought to acceptable levels.
Check "Poll: What everybody keeps their alk. at " thread posted in the reef forum and there is your answer for Alk value.
Good luck!

 

[col]

I wouldn't worry about Ph until tank has cycled.

 

[beefcake]

There is no Alk tester in my kits. What is it? Should I be worried about it ?

 

[broomer5]

I don't know for sure - maybe some other's here can help.
My guess - as we cycle our tanks and initiate the nitrogen cycle - we know the tankwater chemistry is changing ~ right.
We mix up the saltwater - and pH is say 8.2
Everything looks great.
Then we introduce a fish, or piece of shrimp or die off from live rock ~ and we start to see measureable amounts of ammonia/ammonium.
As the bacteria population explodes with this new ammonia food source - we start seeing other "nitrogen" compounds ~ such as nitrite.
Then the nitrate.
I'm no chemist - so I can't say for sure - but I'd bet that the pH drop in a cycling tank is due to various acids that are being formed.
Acids have H+ ions in their structure
So possibly - some of the NO2 nitrite forms with free H+ ions that are always available in the tankwater - and forms nitrous acid HNO2 ?
Possibly the nitrate that is being produced bonds with some free hydrogen ions and becomes HNO3 nitric acid ?
I think this has something to do with the drop in pH.
My tanks pH have always dropped somewhat during the initial cycle too.
Note: They typical pH swings we see in our tanks are normally not present until we either have fish, algae or more often a combination of both.
It's a CO2 gas thing - and has little to do with the dropping pH in a newly set up cycling tank. I'm pretty sure the new tank pH drops is due to the new acids that are forming.

 

[barracuda]

I completely agree with Broomer5 statement and just wanna make an addition to his words. Our sea water has a PH of about 8.2 . It's more alkaline, or in other words more basic. Whatever decays within the system, it produces acids. (PH measured from 1 - 14, where 1-7 is acids, 7-14 basic, alkaline) Due to low PH value of the acids, our sea water PH tends to drop. IMO When your first part of cycle will be completed (Ammonia at 0.0ppm and nitrites are high), then your PH will be much more stable. When i was cycling my tanks and adjusting PH, i was adjusting the Alkalinity also. I never noticed PH drops during the cycle.
Beefcake, you will need this test if you want to run saltwater tank. You can buy it online also.

 

[beefcake]

Maybe I'll pick up a test kit for that tomorrow. It almost sounds as if I was to change the Alkaline level, the Ph would change with it. Is this the case ? I'm a bit confused on this issue. I also heard that putting in calcium has an effect on alk levels too. I do have a KH test unit. I've noticed most test kits are KH/Alk combined. Are they the same thing?
Hopefully I can figure this out with a little help.

 

[barracuda]

There are some products, that are responsible for Alkalinity adjustments. I read about Seachem's REEF BUILDER. When i had low alk in my tank i used Tropic Marin's TRIPPLE BUFFER. Worked very good for me without affecting PH. Just don't use calcium additive during the alkalinity adjustment.

 

[captgut]

5 days into cycle and ph went from 8.3 to 8.6 amonia is top of scale no idea what or if this means anything using only what
used to be live rock to cycle

 

[barracuda]

I personally wouldn't worry about PH 8.6 at this time. High ammonia indicates that your cycle has begun. Ammonia now is the food for your nitrifying bacteria. Ammonia should fall down within next week or so. Meanwhile nitrite should rise. When nitrite goes up it indicates that first type of nitrifying bacteria started to multiply. Then the same thing will happen with the second type of bacteria, which converts nitrite to nitrate.