Need Help. Mysterious PH swing

[sealed]

40 gal dis. reef w 20 gal sump

2/27 Ph 8.2 DKH 11
3/4 PH 8.3 DKH 10
3/10 PH 8.3 DKH 10
3/14 Ph 8.3 DKH 10
3/14 Added G Bubble tip anemone and small drag of GSP
3/15 Ph 8.6 DKH 10 ( 10 gal water change after 8.6 reading)
3/16 Ph 8.6 DKH 10

Calc has stayed at abt 490 ppm
Haven’t done anything expect 10 gal water change (3/15) and addition of livestock above (3/14)
What’s up with this spike in PH?

 

[Hurricane Aquatics]

40 gal dis. reef w 20 gal sump

2/27 Ph 8.2 DKH 11
3/4 PH 8.3 DKH 10
3/10 PH 8.3 DKH 10
3/14 Ph 8.3 DKH 10
3/14 Added G Bubble tip anemone and small drag of GSP
3/15 Ph 8.6 DKH 10 ( 10 gal water change after 8.6 reading)
3/16 Ph 8.6 DKH 10

Calc has stayed at abt 490 ppm
Haven’t done anything expect 10 gal water change (3/15) and addition of livestock above (3/14)
What’s up with this spike in PH?

What salt are you using? From the looks of those parameters I would guess Reef Crystals.

 

[Sean Clark]

Measurement error.

 

[Randy Holmes-Farley]

You indicated in your duplicate thread in the chem forum that the two high readings were for a new and not calibrated pH meter. Problem solved. Always calibrate a new ph meter.

 

[sealed]

What salt are you using? From the looks of those parameters I would guess Reef Crystals.

Yep