Using Muriatic Acid to Lower Alk

[c4haskett]

I use regular IO salt mix and consistently get around 10.5 Alk, 410 Cal and 1250 Mag. I like my Alk lower around 9 so I use muriatic acid to lower alk in freshly made salt. I notice when I do this my calc jumps to about 470 and mag 1500 plus. Is this normal? Any way to mitigate this? Any alternatives other than switching brands?

 

[Randy Holmes-Farley]

Are you talking about calcium in the new salt water, or the tank?

nothing should rise from that muriatic acid addition (assuming it was not contaminated), except you have prevented the precipitation of calcium carbonate.

Folks doing it in a barrel show a spotless barrel while previously they would see precipitated calcium carbonate. So it is higher, but only as high as the mix originally contained.

FWIW, I do not believe the magnesium result can be accurate, unless it's a bad batch.

 

[homer1475]

I've been using muriatic acid to lower ALK in normal purple box IO for decades. Not one single time have I ever seen calcium nor magnesium raise after dosing acid.

 

[GarrettT]

I like my Alk lower around 9 so I use muriatic acid to lower alk in freshly made salt. I notice when I do this my calc jumps to about 470 and mag 1500 plus. Is this normal? Any way to mitigate this? Any alternatives other than switching brands?

I add about 8ml of MA to my IO salt every week. It has never affected my ca or mg levels.

 

[BroccoliFarmer]

I add about 8ml of MA to my IO salt every week. It has never affected my ca or mg levels.

Out of curiosity what is your water batch size and what is your before and after alk? I have been keeping a high alk and I have been told that part of my problems are stemming from keeping alk at 11ish. Was contemplating bringing my alk down but am nervous about breaking what I have going right.

 

[GarrettT]

Out of curiosity what is your water batch size and what is your before and after alk? I have been keeping a high alk and I have been told that part of my problems are stemming from keeping alk at 11ish. Was contemplating bringing my alk down but am nervous about breaking what I have going right.

About 25 gallons. Brings Alkalinity from 11 to 8 dkh. My last batch of MA seemed to be more concentrated and required about half that amount. In the beginning, it's best to work your way up in increments.

Be sure to aerate the water at atleast 24hrs after dosing before adding to the display. I use Transchem.

Transchem Muriatic Acid 1 gal Liquid - Ace Hardware

Professional Strength 31.45% HCL (Muriatic Acid), excellent for pH reduction in swimming pools or to clean and etch masonry surfaces, excellent for pH reduction in all commercial and residential pools.Find the ACID MURIATIC GAL at Ace.

www.acehardware.com

Here's a cut and paste for standard muriatic acid. Yours is more dilute (to get less fumes and cost less):

You can use muriatic acid or certain freshwater buffers to lower alk.
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 in a reef tank, but in new salt water it is fine.

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

 

[jda]

I have never had my calcium rise after adding muriatic acid to IO - been doing it for more than a decade. Did you let the pH rise back up before you tested? Could this affect the test? (I am no chemist and I don't know, just asking).

 

[RobB'z Reef]

I've been using muriatic acid to lower ALK in normal purple box IO for decades. Not one single time have I ever seen calcium nor magnesium raise after dosing acid.

agreed, that's not a thing.

 

[c4haskett]

Sorry guys, I'm not too active on here. Yes I've let PH rise before adding to tank. Come to find. I've had a bad batch of IO. Extremely high levels of calc and mag. I thought it was the muriatic acid having some sort of affect on them but it wasn't.

 

[CrayHawk]

Sorry to revive an old thread, but is muriatic acid a viable long term solution? I use reef crystals, so my alk is always high.

 

[Randy Holmes-Farley]

Sorry to revive an old thread, but is muriatic acid a viable long term solution? I use reef crystals, so my alk is always high.

It's a fine way to lower alkalinity in new salt water.

So is sodium bisulfate, which may be safer to use being a solid and not fuming.

 

[BigReef~LittleWorld]

I have been in swimming pool service for a bit, and realized I'm using pretty much the same chemicals and slowly been trying them here and there. I have crazy high alk at the moment, and just started trying out the pool acid and I sure hope it works. It's really good to have this info to make me feel less crazy.

 

[Randy Holmes-Farley]

I have crazy high alk at the moment, and just started trying out the pool acid and I sure hope it works. It's really good to have this info to make me feel less crazy.

How high?

 

[BigReef~LittleWorld]

How high?

well if I told you. id have to tell you the myriad of other problematic reasons its my own fault..... but
I usually keep a little high just because it's always been the case, recently I went from my usual 10. something and shot up to 14.4 so did a water change really quick. oops now I'm 15 or something and tank still looks good, but I added a little Monti frag and it told me I needed to check. which is how I discovered the high number.
I am a pool person and have lots of chems to choose from. last night I added 5ml acid to a 5 gallon container and this morning the all is back down to 8 in the container. I put another ten gallons in a mixing bucket with 10ml acid and an air stone, watching to see what it looks like later. ph plummeted of course in the first container, but after a day the orig ph dive came back up to around 7.5, only around 8 hours post dose.
so I have a little bit to look forward to this evening post work.
also happened to notice my pool test kit gets the all reading to read the same in whole numbers at least, so I can now check all in a flash and very cheap.