Suggested Daily Alkalinity Increase when adjusting dKH

[CayoHueso]

What's a safe daily increase in alkalinity levels that will not stress out corals? I've seen several different numbers. BRS's calculator recommends not increasing by more than 1.5 dKH in one day. That seems like a pretty high jump in one day. WWC's videos mention not increasing by more than .5 or 1 dKH over a period of week.

 

[Randy Holmes-Farley Verified Community Expert]

IMO, it depends on where you start, and where you want to finish, but a 0.5 dKH per day rise is usually slow enough.

 

[CayoHueso]

IMO, it depends on where you start, and where you want to finish, but a 0.5 dKH per day rise is usually slow enough.

Currently sitting at 7.9 dKH (and 7.97 pH) right now after a weekly water change. I was looking to bump to around 8.5 or 9. I have a small mixed reef with a few softies (3 mushrooms), some LPS (Blasto, Duncan, Chalice, Scoly, Candy Cane) and I just added two SPS frags (Montipora and Cyphastrea) and a heavy clean up crew.

 

[Randy Holmes-Farley Verified Community Expert]

Currently sitting at 7.9 dKH (and 7.97 pH) right now after a weekly water change. I was looking to bump to around 8.5 or 9. I have a small mixed reef with a few softies (3 mushrooms), some LPS (Blasto, Duncan, Chalice, Scoly, Candy Cane) and I just added two SPS frags (Montipora and Cyphastrea) and a heavy clean up crew.

So that's a small move and could be done in a few days. :)

 

[skiergd011013]

I have raised 1 full dkh in a day with zero negative effects. I mix up a baking soda solution and dose it in high flow slowly over the course of a few hours. Ill make up a 100 ml solution and just divide it in 3 parts. Pour some in, walk away, go back in a while, pour a little more in etc, and spread it over a few hours. I am now dosing 0.5 dkh a day to meet demand, but may have to bump that up slightly, as over a week i am still slightly dropping in alk. Corals are thriving and coralline is popping up everywhere. My target is 9 dkh because there is wiggle room on both sides of that. I have also watched PH on my milwaukee meter while dosing, and it didnt change the PH enough to register on the meter. Since you just did a wc and, depending on the salt mix, most likely just added some alk already today, i personally would wait until tomorrow, and just mix up a baking soda solution using the BRS calculator, and make the correction to your 9 dkh slowly, over a full day. Remember to subtract a few gallons from your tank volume on the calculator, to compensate for rock, sand etc. For my 20 gallon, i use 18 gallons on the calculator and it works out well when i test alk.

 

[CayoHueso]

Tested again today at the same time and it's reading 7.7 dKH (down from 7.9 dKH same time yesterday).

@Randy Holmes-Farley can you check my math and logic here... Using the BRS calculator if I want to raise the dKH by 0.5 each day until I reach 9 dKH, I'm looking at 10.71ml of the BRS Liquid Sodium bicarbonate formula daily for 3 days. That should put it at 9.2 dKH.

And if it remains at roughly a 0.2 dKH daily consumption (which I will confirm with testing again) I should be able to dose Liquid Soda ash daily at a rate of 2.14ml daily to make up for daily consumption.

 

[Randy Holmes-Farley Verified Community Expert]

I'd need to know the tank volume to check the amounts. Maybe it's posted, but I don't see it.

 

[CayoHueso]

I'd need to know the tank volume to check the amounts. Maybe it's posted, but I don't see it.

it's a 20 gallon AIO, so I put 15 gallons into the calculator to account for rock and sand and everything else

 

[Randy Holmes-Farley Verified Community Expert]

I generally do not know if BRS has accurate calculators, but this one:

https://reef.diesyst.com/chemcalc/chem_calc3.html
gives a boost of 5.3 mL per day of my recipe #1(sodium carbonate solution) and 10.7 for my recipe #2 (sodium bicarbonate solution) which BRS generally uses in their directions.

Soda ash is sodium carbonate. Make sure you are using the right version based on the solid material you have. :)

 

[CayoHueso]

For both the sodium bicarbonate and the sodium carbonate, is it better to dose over a shorter period of time or a longer period of time? I was thinking about spreading the 10.7ml dose out across 12 hours during the day when the pH is higher. My pH is Low, crests around 8.04 and falls to around 7.75 daily. I figure once I get the dKH up with the sodium bicarbonate, switching to soda ash is better since the tank has lower pH.

 

[BryanM]

I'm another user that raised mine 1dkh per day with seemingly no ill side effects.

 

[Randy Holmes-Farley Verified Community Expert]

For both the sodium bicarbonate and the sodium carbonate, is it better to dose over a shorter period of time or a longer period of time? I was thinking about spreading the 10.7ml dose out across 12 hours during the day when the pH is higher. My pH is Low, crests around 8.04 and falls to around 7.75 daily. I figure once I get the dKH up with the sodium bicarbonate, switching to soda ash is better since the tank has lower pH.

Fauna Marin has an idea that bolus dosing of sodium bicarbonate is somehow better than spread out dosing. I've not seen anything to make be accept that hypothesis. Both work OK.

For higher pH additives, I'd spread out the dosing.

 

[skiergd011013]

For both the sodium bicarbonate and the sodium carbonate, is it better to dose over a shorter period of time or a longer period of time? I was thinking about spreading the 10.7ml dose out across 12 hours during the day when the pH is higher. My pH is Low, crests around 8.04 and falls to around 7.75 daily. I figure once I get the dKH up with the sodium bicarbonate, switching to soda ash is better since the tank has lower pH.

How much are you increasing it in one day?

 

[CayoHueso]

How much are you increasing it in one day?

Currently 0.5 dKH daily for the next 3 days for the correction dose. And then 0.2 dKH using the Soda Ash for a daily consumption dose.

 

[skiergd011013]

Currently 0.5 dKH daily for the next 3 days for the correction dose. And then 0.2 dKH using the Soda Ash for a daily consumption dose.

Thats perfectly fine. 0.5 -0.6 is roughly my daily consumption, and i dose this amount daily. Id do the 0.5 dose in two halfs, an hour or so apart, into high flow. Ive done bigger raises than this with zero effects on the inhabitants. I target 9dkh and tank looks great.