Salt mix with higher alk/2part dosing

aaron23 · Feb 9, 2016

Morning Randy!
So yesterday after the pledge incident I did 2 10 gal water changes. It increased my alkalinity from 8 to 9.6. This was very worrisome as I was thinking this spike in alk may cause more problems for my SPS. I use IO salt and I know if alk is lower than what's in the display you can supplement the water with 2part alk, but what if it is higher? How can you lower alk in my situation? Chance salts?

Or if sticking to this salt, make sure to set the alk parameter higher in the tank for 2part dosing?

Randy Holmes-Farley · Feb 9, 2016

Unless this is a ULNS tank it is likely not a concern, but if it is, smaller water changes (not an option in a problem situation) or dropping the alk in the salt mix with a product like muriatic acid may be the best plan. A fair number of folks do that.

It also leads to less precipitation in the mixing container, probably mostly from the very low pH that results initially.

aaron23 · Feb 9, 2016

Would you happen to have a link on how to use muriatic acid? How much to dose in a WC bucket?

Thank you!

Randy Holmes-Farley · Feb 9, 2016

Sure. Here's a typical thread:

https://www.reef2reef.com/threads/h...lower-alkalinity-like-you-can-with-ph.188293/

and here's a copy and paste of my blurb on it:

You can use muriatic acid or certain freshwater buffers.
Both will lower pH similarly and a lot. There's no way around the pH lowering when reducing alkalinity. You do not want to add CO2. You want to remove CO2 from the tank via aeration.

For that reason, it is best to do it in water change water that is aerated to raise pH before using, or to do it very slowly in the tank (over many days).

The "acidity" (that being essentially negative alkalinity) of muriatic acid straight from the bottle is about 11,000 meq/L.

So adding 1/11,000 of the water volume as this acid will drop alkalinity by 1 meq/l (2.8 dKH).

I would not drop more than 1 dKH per day due to the big pH drop.

You'll need to aerate well after adding the acid to blow off the excess CO2 and bring up the pH.

You can also use Seachem Acid Buffer:

http://www.seachem.com/Products/product_pages/AcidBuffer.html