Ph and Alk

[fishsince3]

Hey everyone. A rather sudden issue I've run into in the last week. My tank has suddenly had a constant drop in ph, was running 8.2/3 and is now consistently coming back at 7.7/8. This is coupled with a constant depletion of alk, it was running up near 12 now is coming back around 7/8. Both of these lead me to believe calcium would be low too but calcium is near 400-430 consistently. SG is constantly at 1.025/026. Had my LFS run magnesium and that was in line they said as well.

After dosing the next day both levels are immediately back down. None of the corals are looking happy though the other inverts all seem good.

Husbandry hasn't changed in the last 5-6 months, 30% water change every Sunday, daily glass wipe down with a mag float, clean all pumps every other week, feeding once a day in the AM.

Please help.


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[Vinny Kreyling]

All windows closed with the AC on I would guess.
Could just be more CO2 in the air.
If you get a cool day open the windows & see what happens.

 

[fishsince3]

All windows closed with the AC on I would guess.
Could just be more CO2 in the air.
If you get a cool day open the windows & see what happens.

I read that a few other places. Anyway to kind of simulate it? (in Chicago no cool days coming in any time soon)


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[Uncle99]

MG must be in the 1200-1360 level, otherwise Alk ions are just going to attach to CA ions......test MG and ensure your on the higher end of that range, then slowly bring up Alk, wait 24 hours, retest PH. 7,8 is not a bad number
If you have a skimmer and can pull outside air into the mix that will help
Or CO2 scrubber but that's kinda expensive

 

[bertoni]

I agree that pH at 7.8 is normal for a tank with the windows shut. Lots of Tanks of the Month ran at that level. The drop in alkalinity probably is simply due to coral growth. The ratio of consumption is 2.8 dKH per 20 ppm of calcium, so calcium consumption is hard to measure.

 

[Dr. Reef]

What instrument are you using to measure pH?
Also dosing alkalinity solution will bring up alk but will have a temporary effect on pH. Although if pH of 7.8 is correct then it's not bad. It acceptable.
Alk could be low due to consumption. A healthy reef tank can consume 2-4 dkh per day. Very normal.
Are you using denitrator?

Your corals are not happy because of fluctuating alk and pH.
I wouldn't chase pH but try to keep a constant slow dose of alk solution so the alk remains stable throughout the day. Consistency is the key rather than a number.

Can you ask the lfs to give us the mag result? What was the final number they concluded?

 

[JustAClownFish]

Alk of 12 is way too high anyway. Ph of 7.8-8.2 is fine. Stop stressing. Dose alk to keep it at NSW levels of around 7-8 dkh. If you want to do the chasing number games dose kalkwasser. It’ll bring your ph up.

 

[hkgar]

What is your Mag level?
I know it has been asked but it is an important measurement that is often overlooked.