PH a little low???

[moorea2]

I have 120 gallon display with a 75 gallon sump fuge that just recently finished its cycle.
(Actually I do not know when it finished cycling as I have a ph probe that was not calibrated properly and the PH was reading in the high 9's for about three months. Last week I did a ph test with my kit and found out that the ph probe was wrong recalibrated it and I have between 8.12 - 8.17 all week.)
This evening it dropped to 8.01.
The tank has a bunch of flow between the closed loop system and the return pump.
I have my lights almost on an alternating 24 hour schedule. The florecents in the display tank run from 11:30am – 9:30pm the MH's run from 12:00pm – 9:00pm. The light in the fuge is running from 10:00pm – 10:00am.
I do not know if this makes a difference but I just added a chiller about 30 hours ago. The tank was running hotter then I wanted it. I have a reefkeeper2 and the lights were not on for most of my cycle as the tank was running about 82 - 84 degrees with the hood fan on 24/7 and I had the cuttoff on my lights at 82 degrees. The chiller has kept the tank at a steady 78 - 79 degrees and for a little over 24 hours now my lights have come on and off properly as described above. And now at the end of the day... the PH has dropped to 8.01!
I am topping off an average of 2 gallons a day although sometimes as much as 3 or 4.
My salt levels are fine and I am using DI water.
Other levels:
Alkalinity 3.5 meq/l
Nitrate 7.5 (ish)
Nitrite 0
Free Amonia 0
Total Amonia 0.1 (ish)
I also added 1/2 lb of Chaetomorpha to the fuge yesterday after the chiller got the temp stable.
So what is up with the PH? Now that I have my lighting and heating on track will it continue to drop? Is 8.0 - 8.17 really to low? I've looked at a bunch of low ph posts and those seem to all be in the mid to low 7's. If mine is to low how can I get it up. I do not want to use chemicals or buffers if not necessary.

 

[lion_crazz]

8.0 is not really a low pH. If it drops any further I would say it is low, but it is fine where it is now. Have you tested your calcium level?

 

[moorea2]

Thanks for the reply Lion,
Thanks for the reply, I kind of figured that 8.0 was not too low as all the other post for low ph where in the 7's. My worry is that it will continue to drop (which it has when I posted it was 8.07 now it is 8.05)
My test kit does not contain a calcium test. So I guess I will have to get one.
Now that my cycle has completed I am getting ready to do a water change. Hopefully this will bring up the ph a bit. I made the water last night. It has been sitting with a power head and heater since then.
My problem is I only have one clean 5 gallon bucket. I could get another but it takes my DI sysyem about a day to fill it. I am doing around 3 gallons of top off a day. If I made anymore then 5 gallons not only would a water change take me about 4 days to complete but I would not have the water to do my top off's and my pump would be running dry.
(I know it is about 3 gallons because my DI holding tank is 3 gallons and my top off's usually deplete it and then I still drip water for about an hour after that to get to my line)
So is a weekly 5 gallon change to little for my 120 DT, I have around 53 gallons of water in my fuge?

 

[reefnut]

5g a week is fine if it works for your tank. I'd do a larger water change just coming out of your cycle though. You can go to walmart and get a 40g rubbermade tub and use a powerhead to pump it up to the display tank.
I agree a PH of 8.0 is fine, especially just coming out of a cycle. What you really want to watch is your alkalinity and calcium levels. Alkalinity has a direct effect on PH and calcium has a direct effect on alkalinity as alkalinity has a direct effect on calcium. A alk level of 3.5 meq/l is good with a calcium level of around 430ppm.
Simply put... keep your alkalinity above 3.0meq/l or so and balanced with your calcium and the PH will fall in line unless you have other problems with in the tank. https://www.saltwaterfish.com/vb/showthread.php?t=175205

 

[moorea2]

OK I did the 5 gallon water change. I also added about 2 gallons of top off after the water change.
I added a power head to the fuge for increased flow.
I waited about 3 hours after the water change. My PH increased from 8.04 (this mornings reading) to 8.07 but my alkalinity is now down. The numbers from earlier post are from a few days ago (with the exception of PH as I have a constant reading on my probe and I check it daily.) Todays numbers are:
ph 8.07 (this matches my ph probe exactly)
Alkalinity 2.5
Nitrate 7.5
Nitrite 0
Free Amonia .1 (maybe .2)
Total Amonia .2 (maybe .3)
I have not been adding food or anything to the tank as there is only live rock and sand in there and the addition of the cheato two days ago.
What is going on with my PH and Alkalinity and Amonia (and who knows what my calcium is as I do not have a test kit for that yet) how can I get them back up.

I was planning on ordering my clean up crew tomorrow... should I wait or will this maybe help.
I have started the SLOW process of filling my 5 gallon bucket with DI water a few minutes ago. Should I do another water change as soon as it is ready tomorrow or should I hold off.

 

[reefnut]

Get a second opinion from your LFS on the ammonia. What is the alkalinity of your newly mixed saltwater? also, until you get a calcium reading it's hard to say what's going on with the alkalinity.