Tough Decision: Extreme Ph Swing vs Dose Alk durning lights off (Apex graph provided)

[Koralcrazy]

Hi Everyone,


Please take a look at my daily Ph swing. It has always concerned me, and yes, my probe has been recently calibrated. Everyone states Ph doesn't matter, don't chase it, but this swing is ridiculous. Perhaps I wouldn't be concerned, but I am constantly dealing with very, very slow base bleaching, and slight base recession. In this graph -The first several days I was dosing 24/7. The last couple days I am dosing Alk throughout 14 hours while lights are off and then Calcium during lights on time. Which is better for the health of my sps? It seems alk would be more stable dosing 24/7, but at the same time this dramatic Ph swing is very concerning to me. Any input guys? Anyone else dosing Alk only when lights are off? How much of a swing are you experiencing?

Thanks!

Current Parameters:
Mag 1320
Alk 8.4
Calcium 430

 

[toothman]

wow, is that with kalk. 2 part, reactor.

 

[Koralcrazy]

Just use two part on this tank, dose 70 ml per day

 

[jda]

Confirm the PH readings with a second source. Hobby grade probes can be really horrible, even when tuned. You have a PH Pen?

I swing about 8.10 to 8.29, or so, every day. I have a CaRx which keeps everything pretty steady. I would spread out the dosing all day, otherwise you can/will have alk swings, which are way worse than PH swings.

Seriously, don't chase PH. My most beautiful SPS tank would swing from 7.82 to about 8.25 - it was in the basement with a lot of airborne CO2.

 

[Sisterlimonpot]

Seriously, don't chase PH. My most beautiful SPS tank would swing from 7.82 to about 8.25 - it was in the basement with a lot of airborne CO2.

this^^ +1

 

[offroadodge]

agreed my PH goes from 8.31 to 7.89. I watch the corals and let them tell me whats going on.

 

[GroktheCube]

Is the probe or its wire near the lights?

 

[Koralcrazy]

The probe is in the sump, in a dark spot...I've tested manually, it is pretty close

 

[Koralcrazy]

agreed my PH goes from 8.31 to 7.89. I watch the corals and let them tell me whats going on.

Ya, I'm watching the corals and they aren't doing good, random bleaching at base...the only thing out of line is the extreme high ph and extreme swing...

 

[emerald crab]

I dose Ca and Alk at the same time, in different areas with high flow in the sump. 1.7 ml/dose. One dose every 1/2 hour. It works for me.

 

[PeTe PoLyP]

Is the probe or its wire near the lights?

Does this make a difference? Maybe I should move mine

 

[dkeller_nc]

Your pH graph isn't reflecting the addition of kalkwasser, it's reflecting the normal photosynthetic cycle pH swing. Your change has minimized the pH swing to some extent since you're dosing alkalinity when the pH of the tank is going down because of the respiration of CO2.

If you really want to minimize these pH swings (personally, I wouldn't bother), I would add an airline so that your skimmer's air intake isn't coming from the airspace in your sump. This will assist with stripping the CO2 given off by photosynthetic organisms from the tank water at night, and may also minimize the pH rise during the day by actually putting CO2 back into the water from teh surrounding air.

Also, your post mentions adding kalk at night and then "calcium" by day. If you mean calcium in the sense of adding only a calcium chloride solution, you're likely to eventually wind up with a system depleted in alkalinity, since the kalkwasser is by definition adding a balanced alkalinity/calcium mixture, and the calcium added by day is only adding calcium, not alkalinity (so the ratios are out of whack).