ph @ 7.92? good or bad

[Islander84]

during the day my ph sits steady at 7.92....at night it hits about 7.87 is this good or bad. i have a calcium reactor running and gfo...but also running a refugium full of chaeto and a reef octopus skimmer 3000lph.....the tank is 144 gal w 75 gal sump

[Randy Holmes-Farley]

That's OK. Not perfect, but certainly fine.

I discuss such issues here:

The "How To" Guide to Reef Aquarium Chemistry for Beginners, Part 3: pH
http://reefkeeping.com/issues/2007-05/rhf/index.php

from it:

What is the Acceptable pH Range for Reef Aquaria?
The acceptable pH range for reef aquaria is an opinion, rather than a clearly defined fact, and certainly varies based on who is providing the opinion. This range also may be quite different from the "optimal" range. Justifying what is optimal, however, is much more problematic than justifying what is simply acceptable. I suggest that the pH of natural seawater, about 8.2, is an appropriate goal, but reef aquaria can clearly operate in a wide range of pH values with varying degrees of success. The pH of highly successful coral reef aquaria often deviates substantially from pH 8.2 for at least part of the day. In my opinion, the pH range from 7.8 to 8.5 is a acceptable for reef aquaria, with several caveats. These are:

1. That the alkalinity is at least 2.5 meq/L (7 dKH) and preferably higher at the lower end of this pH range. This statement is based partly on the fact that many reef aquaria operate acceptably in the pH 7.8 to 8.0 range, but many of the best examples of these types of aquaria incorporate calcium carbonate/carbon dioxide reactors which, while tending to lower the pH, also tend to keep the carbonate alkalinity fairly high (at or above 3 meq/L.). In this case, any problems associated with calcification at these lower pH values may be offset by the higher alkalinity. Low pH stresses calcifying organisms primarily by making it harder for them to obtain sufficient carbonate to deposit skeletons. Raising the alkalinity may mitigate this difficulty by supplying extra bicarbonate to them.

2. That the calcium level is at least 400 ppm. Calcification becomes more difficult as the pH falls, and it also becomes more difficult as the calcium level falls. It would not be desirable to push all of the extremes of pH, alkalinity and calcium at the same time. So if the pH is on the low side and cannot be easily changed (such as in an aquarium with a CaCO3/CO2 reactor), at least make sure that the calcium level is acceptable (~400-450 ppm). Likewise, one of the problems at higher pH (above, say, 8.2, but becoming progressively more problematic with each incremental rise) is the abiotic precipitation of calcium carbonate, resulting in a drop in calcium and alkalinity, and the resultant clogging of heaters and pump impellers. If the aquarium's pH is 8.4 or higher (as often happens in an aquarium using limewater), then it is especially important that both the calcium and alkalinity levels be suitably maintained (that is, neither too low, inhibiting biological calcification, nor too high, causing excessive abiotic precipitation on equipment).

[Gangous]

Randy my cal is 420 my alk 9-10 and ph usually aroung 8.4 is that good?

[Rockys_Pride]

during the day my ph sits steady at 7.92....at night it hits about 7.87 is this good or bad. i have a calcium reactor running and gfo...but also running a refugium full of chaeto and a reef octopus skimmer 3000lph.....the tank is 144 gal w 75 gal sump

Look at your coral, is anything receding? If not, look into replacing/recalibrating your probe.

Sent from my DROIDX using Tapatalk

[Randy Holmes-Farley]

Gangous, yes that just perfect, IMO. :)

Look at your coral, is anything receding? If not, look into replacing/recalibrating your probe.

Why do you suggest there is a probe problem?

[Islander84]

i caliberated probe in 4 and 10 solution and while it was caliberating it had off numbers(11.1 or 10.9 or something) but once the caliberation was completed and i stuck the probe in the 10 solution it was right on the money(10.0) so im assuming the probe is fine but i could be wrong

[Islander84]

Randy what do you suggest i do to bring or mantain ph around 8.2 or so

[Randy Holmes-Farley]

I wouldn't bother to do anything, but if you want to raise it, limewater and/or fresher air in the room are usually the best options.

This has more:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

[jeffreylesser]

i calibrated probe in 4 and 10 solution and while it was calibrating it had off numbers(11.1 or 10.9 or something) but once the calibration was completed and i stuck the probe in the 10 solution it was right on the money(10.0) so I'm assuming the probe is fine but i could be wrong

I have always calibrated with 7Ph and 10Ph solutions for the tank, and 4Ph and 7Ph solutions for the reactor. I am not sure if calibrating with 4 and 10 will misrepresent your Ph or not. Worst case I doubt it would be by very much. How long ago did you calibrate? I find at about 4-6 months my probes start to drift up or down in measurement(but usually up). With that said, my night time Ph is 7.95 - 8.00, and my tank is doing great. I wouldn't worry too much if your tank is happy.

[Islander84]

Maybe it was 7 instead of 4 I really don't remember its been a few months.its getting up to about 7.95 by the end of photoperiod

[Randy Holmes-Farley]

Any of those combinations should be pretty good for calibration if the fluids are accurate. Havign the calibration span the range of use is certainly the best way. :)

[jeffreylesser]

If you want piece of mind, Get new 7 and 10 solutions and recalibrate, at my LFS I think they are 1.95 each, so no great expense. If your probes are temp compensated, then float the solutions in the tank before you start. If your probes are not temp compensated then you probably want to get the packets to whatever temperature on them reads the correct Ph (There is usually a chart on the Pinpoint / Milwaukee solutions, probably somewhere around 77 / 78 ). Clean your probes before hand in a vinegar and water solution.

[Paco]

For what it's worth, due to a high number of humans in my house (seven, soon to be eight), we have high indoor CO2, especially in the summer when the A/C is on full time. My tank's range is regularly 7.5 overnight to 7.9 during the day. I used to stress about it more but it doesn't seem to be a problem. Things are growing and when they are not, it's more likely due to my own failures.

I use kalk with vinegar for supplementation and keep the KH around 9 dKH. I haven't measured calcium in ages but it should be around 425ish.