Is my pH swinging too high?

[tx_kyle]

I have a 120G display tank w/ 40G sump. System has been up 3 months. I'm currently hosting some softies but just added a couple of SPS frags. I've been manually dousing baking soda and Kent Turbo Calcium. No problems keeping Ca up but alkalinity has been lower than desired at around 7.

Starting Noon Monday, I began dousing kalkwasser (Mrs. Wages- 1 tsp/gal) via my RO/DI make-up water. Starting parms were

8.24 pH
7.4 Alk
390 CA

By 8:30 AM Wednesday (44.5 elapsed hours), I had dripped 3 gal of make-up. My parms were

8.32 pH
7.7 Alk
440 Ca

I added 3 tsp baking soda to balance alkalinity relative to Ca and to lower pH.

Currently, 5PM Thursday (32.5 hours incremental), and I've dripped an additional 1.9 gal of RO/DI and my pH is running 8.47. I'll check Alk/Ca in the morning.

I'm concerned my pH is running a little high. What do yall think? Should I just let the system stabilize a little longer or should I be doing something proactively? Thanks for your help!

[boxfishpooalot]

If it gets to 8.5+ I would stop the kalkwasser. Running a skimmer can reduce that effect largly.

The ph rose fine over a short time period, should not have been stressfull.

You might want to consider a refugium to combat low ph.

Do you have a protein skimmer on this tank?

[tx_kyle]

Yes I do have a protein skimmer. ASM G4+.

I also have refugium w/ macro algae. It's lamp runs 6PM to 12 noon. My main lights run 8:30AM to 5:00 PM.

[boxfishpooalot]

Ok, perhaps your just adding too much limewater. If you want to continue dosing this without the high ph, lower you dosage or drip/flow rate. :)

Also, are your windows open or closed? I find it very hard to get a ph that high without dripping lime and having the widows open. If I close the windows, ph can get to 7.8 easy, especially at night.

Or you can dose limewater when the refugium is off. Because at night the macro will release Co2 lowering the ph.

[jdieck]

<a href=showthread.php?s=&postid=8241074#post8241074 target=_blank>Originally posted</a> by tx_kyle

I'm concerned my pH is running a little high. What do yall think? Should I just let the system stabilize a little longer or should I be doing something proactively? Thanks for your help!

Kyle:
Limewater is a balanced additive that will add 20 ppm of Calcium for every 2.8 dKh, the same way both are consumed by corals and precipitation.
Limewater also rises PH as you may have noticed.
For this two reasons it is not recommended to use limewater to increase levels nor to increase one level over the other but rather it is a very fine way to "maintain" your levels once they are balanced.

When adding just the requirements to maintain your levels your PH will not increase to dangerous levels

So try adjusting your levels of Calcium and Alkalinity individually to your targeted levels using calcium chloride and baking soda, once the level is up to target and balanced then start the lime addition but adjust the amount or the concentration of the solution just to match the consumption.

[Randy Holmes-Farley]

I'm concerned my pH is running a little high. What do yall think?

I don't think the pH is excessive. All of the posted values look fine. :)

[tx_kyle]

Here are my Fri 8am readings. I've dripped 1.1 gal of make-up/kalkwasser in the past 15 hours.

Temp 79.0
pH 8.27
Sal 1.026
Alk 8.3 dKH
Ca 400 ppm
Mg 1350 ppm

I'm will continue to watch the pH swing during the day but I'm feeling better about the numbers. Thanks to everyone for their advice.

[Randy Holmes-Farley]

:thumbsup:

looks perfect to me.

Happy Reefing. :)