Muriatic Acid & Water Hardness

[GregSch]

I have a 3000 gallon pond that has some exposed concrete in it, so in order to keep the ph correct I have been using muriatic acid (very sparingly and it has worked very well so far). The problem I now discovered is that the water is very soft (the KH is less than one degree). Does anyone know if the muriatic acid is what made the water so soft? And what is the best way to bring the hardness back up without increasing the ph?

[Nancy M.]

Quote: Originally Posted by GregSch I have a 3000 gallon pond that has some exposed concrete in it, so in order to keep the ph correct I have been using muriatic acid (very sparingly and it has worked very well so far). The problem I now discovered is that the water is very soft (the KH is less than one degree). Does anyone know if the muriatic acid is what made the water so soft? And what is the best way to bring the hardness back up without increasing the ph?

Greg
What is your ph without the muriatic acid added?

[PapaBear]

I'm not a big fan of Muratic acid in an active pond. That would have been better done before it was populated with fish, but since you are stocked here's my 2 cents worth.
STOP USING THE ACID!
It will be much safer for your Koi and filters if you use water changes to keep your ph in check. The acid will break precipitate carbonates out of your water and drop the bottom out of your kh numbers, which will severely mess with your water chemistry, filtration, and Koi metabolism.
Start by giving some hard numbers on your pond so more detailed advice can be given to your specific situation.
Source water ph, kh, gh. (let the water stand 4-5 hrs or aerate well for 30 min to stabilize ph before testing)
What is your stocking level, feeding schedule/volume, pond water parameters, (ph, kh, gh, Ammonia, Nitrite, Nitrate, temperature) and a good description of your pond width, depth, length, filtration, etc...
Pictures are always good too.

[RookieKoiGuy]

No more muriatic acid...it burns gills and kills good bio

RookieKoiGuy Grow out Form

[MCA]

remove the fish
add acid to drive the ph to around 5
keep adding acid until the pond stays around 5 for at least 2 days
drain the pond and wash and clean it , pipes...etc.
refill and add apprpriate dechlor

never again add acid to the pond with fish in situ!!!

cure the pond....not the fish.

[KoiCop]

Agree with the others re: using acid with fish in the pond.

As for your original question, that would depend upon:

1. Your basline (tap or well) parameters (pH, KH & GH)
2. Your pond parameters (pH, KH & GH)
3. Frequency & size of water changes

[Auntiesue]

Correct me if I'm wrong, but my understanding is that acid will only effect the KH, not the GH. It's the GH level that tells us if your water is hard or soft.

I agree with all of the others, do not use acid to control your water condition. With little or no KH you are risking a crash. I would start a series of water changes pretty quickly.

[MCA]

Water changes are not really the solution unless fresh water is free. He needs to burn off the lime in the exposed concrete. So just like curing a concrete pond, you remove fish, bypass filters, and drop the ph until it stays low. After water change, cleaning, water change....the kh and ph should not be going through the roof....at least because of lime in the exposed concrete.