How to raise alkalinity quickly?

[BradB]

I run a mostly Acropora 270 gallon display with 2 part dosing. If this drifts down (or rarely up) over several tests, I adjust the amount I dose. Occasionally, my dosing pump clogs, or I am dosing too little too long without testing, or for some other reason my Alkalinity or Calcium is low. I am not worried about Calcium. I target 10 dHk.

What is the quickest safe rate to raise it and how do I best do so? For example, if I were at 8dHk, I could use the online calculators to figure out exactly how much to raise 2dHk and just dump this all at once (slowly), but measurement and manual error could put me as high as 11dHk and I don't want to follow stressing my corals with too low alkalinity with stress from a rapid rise to too high alkalinity. Better to dose at least twice with a test in between. But I worry that testing too soon after dosing is inaccurate. How soon can I retest reliably? What usually happens is I test every day and dose conservatively after, but that ends up being a lot of testing and dosing and chasing numbers over a week or longer. Can someone recommend an optimal rate?

I also want to point out that going from 8dHk to 10dHk with corals grown in 10dHk that rapidly dropped to 8dHk is a much different scenario than raising 8dHk to 10dHk with corals that have grown for years under a stable 8dHk.

 

[arking_mark]

Rule of thumb is typically 0.25dkh per dose and 1dKH per day.

You can retest almost immediately with most products...just give it a little time to "mix" in the tank.

I just use baking soda...

 

[Randy Holmes-Farley Verified Community Expert]

I agree that the above post reasonably answers the questions.

 

[BradB]

If you are dosing 4 times a day, I am being way too conservative waiting 24 hours after I dose to test. How long is "almost immediately"? Is waiting an hour long enough?

I am either using Sodium Carbonate or Sodium Bicarbonate.

 

[Randy Holmes-Farley Verified Community Expert]

If you are dosing 4 times a day, I am being way too conservative waiting 24 hours after I dose to test. How long is "almost immediately"? Is waiting an hour long enough?

I am either using Sodium Carbonate or Sodium Bicarbonate.

Think of it like food coloring. How long after adding it would be the tank be a single color?

In a sumpless system it would be only a few minutes.

In a system with extended sumps and refugia, it will be longer.

 

[BradB]

I've never added food coloring to my tank, so I have no idea. Is food coloring reef safe? If so, it might be a good way to tell.

Conservatively, I turn over my display 6 times per hour. So this would be throughly mixed in 10 minutes if all the water in the display went to the sump before any water from the sump went back down. Of course, water doesn't work that way. I'd have to do the calculus, but I believe the food coloring would always be higher in the sump but the limit of the difference would go to zero.

 

[Tcook]

I've never added food coloring to my tank, so I have no idea. Is food coloring reef safe? If so, it might be a good way to tell.

Conservatively, I turn over my display 6 times per hour. So this would be throughly mixed in 10 minutes if all the water in the display went to the sump before any water from the sump went back down. Of course, water doesn't work that way. I'd have to do the calculus, but I believe the food coloring would always be higher in the sump but the limit of the difference would go to zero.

Don't put food coloring in your tank. It was for illustrative/ imaginary purposes. In my 120 it would be about 20 minutes.

 

[HudsonReefer2.0]

I've never added food coloring to my tank, so I have no idea. Is food coloring reef safe? If so, it might be a good way to tell.

Conservatively, I turn over my display 6 times per hour. So this would be throughly mixed in 10 minutes if all the water in the display went to the sump before any water from the sump went back down. Of course, water doesn't work that way. I'd have to do the calculus, but I believe the food coloring would always be higher in the sump but the limit of the difference would go to zero.

Randy was making an analogy to its dissipation based on diffeeent tank scenarios. Not suggesting the addition of food coloring.

 

[Randy Holmes-Farley Verified Community Expert]

I've never added food coloring to my tank, so I have no idea. Is food coloring reef safe? If so, it might be a good way to tell.

Conservatively, I turn over my display 6 times per hour. So this would be throughly mixed in 10 minutes if all the water in the display went to the sump before any water from the sump went back down. Of course, water doesn't work that way. I'd have to do the calculus, but I believe the food coloring would always be higher in the sump but the limit of the difference would go to zero.

Put a drop of food coloring in a glass of tap water and stir. That indicates how fast dissolved chemicals mix in.

I agree it will take longer to get out of a sump. An hour on most systems would be adequate.