pH swing? Dosing sodium bicarbonate "baking soda"

[DanSavesTheDay]

I've just noticed some RTN on a tort frag. I haven't had any alk swings since this frag was added and it was in a low light area of the tank

Could it possibly be a pH swing? My tank size is 88gallons and I usually dose my alk "baking soda" 0.6 tsp mixed in warm rodi dosed into sump at night. My alkalinity dose replenishes the daily usage of 0.3 per day. Could the baking soda lower the pH of the tank with it already being lowered from the lights being out. I have a refugium growing chaeto with an algae scrubber running 24/7.

I would love some help/input. I typically dose my alkalinity when the lights are out and was wondering if I should split it up through the day while the lights are on.

Thank you

 

[SeaDweller]

Probably not much. I dose straight baking soda to my DT when I want to bring my alk up to a certain range.

 

[C. Eymann]

Probably not much. I dose straight baking soda to my DT when I want to bring my alk up to a certain range.

^^^ agreed.


If you are going to dose it at night, why not throw that baking soda in a 350° oven for 1 hour to drive off the CO2, increasing potency and making its pH impact opposite, as in the baked baking soda will raise pH vs lower it.

 

[homer1475]

Soda ash(baked baking soda) wil increase PH instead of a slightly lowering effect of plain baking soda. It is also nearly twice as strong, so make sure you check your calculations before adding it.

Google Randy's DIY 2 part and use the ALK recipe 1.

 

[DanSavesTheDay]

It turns out that all my issues were from a faulty heater. It was keeping the tank temp around 82 degrees

 

[jda]

Like those above, I do not think that pH was your problem. Also do not think that temp at 82 was a huge deal - while I would definitely get it back down to 78, or so, I would keep looking for other possible issues like general stability or lighting.

 

[TX_Punisher]

Baked baking soda also raises alk as well, does it not?

Never used it personally but was curious about that.

 

[homer1475]

[/QUOTE]

Baked baking soda also raises alk as well, does it not?

Never used it personally but was curious about that.

Soda ash(baked baking soda) will increase PH instead of a slightly lowering effect of plain baking soda. It is also nearly twice as strong, so make sure you check your calculations before adding it.

Google Randy's DIY 2 part and use the ALK recipe 1.

 

[Bret Brinkmann]

I have a montipora and leptoseris that went through an alkalinity spike of 1.3dKH. The alkalinity is back down to normal now. The lepto is showing some necrosis and the monti is getting pale in one spot. My daily pH swing is from 8.2 to 8.5 during the 8 hour lights on time and then back down to 8.2 for the lights off portion. Is this swing too much for these corals? Did the alkalinity spike do its damage already and I just need to wait and see what happens?

I also don't have a lot of flow. Three MP10s at the 3rd from lowest setting. They are close to the powerheads, but would too little flow cause necrosis?