pH drops like a rock

[Mano]

So my tank has been cycling for just under a month and all the water parameters are awesome, N03 is almost completely gone and I'm almost ready to add fish... except my pH keeps dropping. Yes, doing a water change makes a great difference, but it only lasts a few days.

 

An example, On the 15th I performed a water change, and 12 hours later, the pH registered at 8.2. I thought I was good to go, but when I tested it today, the 17th, it was back down to 7.8. I have a good bit of surface agitation in the tank and the lights run for 8 hours a day. I use RO/DI water with ultraviolet treatment at every water change, and generally do 2 gallon changes for my 10g tank.

 

I know you are supposed to leave a cycling tank alone to let it 'work itself out,' but I am wondering if I can look at adding a pH buffer since the tank it so near the end of the cycle. I have also read that adding an air stone to the tank can help raise the pH. Thoughts, comments, solutions? I appreciate it all.

[glennr1978]

be patient. this is normal in such a young tank.

[TimothyUhl]

Eventually, you'll need to start testing your water anyhow. Go ahead and get a kit. I use the API Saltwater and API Reef test kits both.

 

Test your DKH/Carbonate Hardness specifically. If it's already high (8-12) then adding buffer will do you no good and your PH swings are caused by something else. If it's low, then increasing your alkalinity with an additive could help.

 

Diagnose first, then prescribe.

 

ETA: If I'm not mistaken, most agree that performing water changes during a cycle slows it down.

[reefdan]

ETA: If I'm not mistaken, most agree that performing water changes during a cycle slows it down.

 

yeah slows it down but makes it easier on any hitchhikers

[TimothyUhl]

yeah slows it down but makes it easier on any hitchhikers

 

Excellent point.

[Mr. Fosi]

... I am wondering if I can look at adding a pH buffer since the tank it so near the end of the cycle. I have also read that adding an air stone to the tank can help raise the pH.

 

No, don't think about pH buffer.

 

Are you testing at the same time of day each day?

 

When during your light cycle are you doing these pH tests?

 

An airstone (or a skimmer) can help boost your pH if your pH is being dragged down by excess dissolved CO₂ but before you do that, you should answer the questions above.