My tap water is in the high 8.4 ph area. Any "natural" ways to lower it?

[David W. Russell]

I just got my system running and found out that my tap water is high in ph.  Any natural ways to lower it before I add my fish??

[Leo White Bear]

you can add either calcium carbinate or potassium carbinate to lower the pH of your water.  Your plants will also appreciate the minerials of either.

[Mike Creuzer]

I don't think adding carbonates are what's called for here. They would bring water that is lower than 7.2 up to that PH level.

You could create carbonates in the water by adding Carbon Dioxide which would help acidify the water. You could also add vinegar, which would be matabolised over time, creating carbonates in the water as well and the PH lowering will last longer than the actual vinegar does. If you use apple-cider vinegar, you add a lot of good trace minerals as well.

At least that's my understanding of things. It's been years since I've opened my chemistry books. I could be wrong here.

Leo White Bear said:

you can add either calcium carbinate or potassium carbinate to lower the pH of your water.  Your plants will also appreciate the minerials of either.

[Jim Troyer]

We have 8.3 pH water out of the tap here in Arizona. 

We add pool acid to manage the pH.  It's also known as muratic acid and can be found in grocery stores and pool supply stores in most locals.

[Sheri Schmeckpeper]

Whoops, Mike's right! You want an acid to lower your PH. Carbonates do the opposite.  We tried peat & vinegar (don't try lemon juice!) & other methods, but they don't drop it much and certainly not enough to kick the buffer. For water that's 8.4 you'd have to add a LOT of vinegar.

Jim's right, we use muriatic acid because our PH is very high like yours. Muriatic acid is safe, so don't be afraid of it. We were using about 2.5 oz to 50 gallons (in a separate prep barrel - don't add it straight to the system because you may kill fish, plants, and/or bacteria) and it would take it down to 6.8. There are two concentrations of acid, though, so start with 1.5 oz to 50 gal and see what it does (I don't remember what ours is offhand).

Bigger systems will auto-adjust as they mature, so this may be a temporary thing if your system is large enough. 

[Mike Creuzer]

Muratic acid is the commercial name for very dilute Hydrochloric acid. I am not sure I would call it 'safe', but it's safe enough to handle with reasonable care.

I am thinking that the plants & fish won't consume parts of the muratic acid like they would with a phosphoric based acid, so it will last longer in your system. Don't try to move the full 1.5 PH points all at once. Do the math to move it half a point max at a time, and then wait about 3 days with the pumps running. There is a lot of chemistry that happens when you make big changes, and it's easy to over-shoot due to unforeseen side-reactions.

With that high of a GH / KH it would take a lot to buffer it down to ~7. You may be better off building a solar-still auto top of system or finding an RO unit.

Sheri Schmeckpeper said:

Jim's right, we use muriatic acid because our PH is very high like yours. Muriatic acid is safe, so don't be afraid of it. We were using about 2.5 oz to 50 gallons (in a separate prep barrel - don't add it straight to the system because you may kill fish, plants, and/or bacteria) and it would take it down to 6.8. There are two concentrations of acid, though, so start with 1.5 oz to 50 gal and see what it does (I don't remember what ours is offhand).

Bigger systems will auto-adjust as they mature, so this may be a temporary thing if your system is large enough. 

[Mike Creuzer]

Another thing, fill a bucket full of tap water and let it sit for a few days, than test. The PH at the tap, and the PH after the gasses have equalized will often time change a few tenths.

Also, the plant and fish biological activities tend to drive the PH down over time. Getting things a bit on the high side, but livable for the plants and veg is better than getting it on the low side.

[Leo White Bear]

WHOOPS!! I replied to the wrong post one from another group.  Please disreguard my last posting to use carbonated to lower the pH.

[Linda Logan]

I have used HCL but now I would use phosphoric acid now.  After the pH goes down you will have some phosphorus

[Robert Rowe]

@David W. Russell - First - Don't rush it! - It wont hurt your fish, unless they come from an evironment with low PH. Add acid (read the book) - Don't rush it. My system, after a year, varies from 7.4 to 8.0. when its high, I add an ounce of hydrochloric acid and check it again the next day and repeat if necessary. My fish and my plants are happy and I feel no pain.

 

[Colin]

I use Lemon juice in my system when I need to lower Ph. The plus is that Lemon juice is relatively weak compared to a lot of the stronger commercial "Ph Up" acids so it is not so easy to over do it and harder to harm your fish, also a plus for me that my neighbor has a lemon tree that constantly drops lemons onto my property which are perfect for the task.

If I need to lower the Ph I simply pull a Lemon off my tree and squeeze it into one of my grow beds. In a couple of days I check the Ph again and if needed, do it again. Couldn't be easier.

[TCLynx]

Here are some blog posts about pH and tap water that might help enlighten.

ph and tap water

pH and Tap water2

To lower pH, you need to use acid or remove the hardness (Remove, carbonates and bicarbonates and alkalinity) somehow.  How much acid is needed is going to be more related to the amount of hardness in the water rather than the actual pH of the water so it can be really tricky to figure out how much acid to use simply based on your starting pH and what some one else does somewhere else.  They may have far more hardness they are counteracting than you do so if you add the same amount of acid you may overshoot.

Since you say the system is brand spanking new, you could probably go ahead and do some acid adjustment right in the system since you don't yet have anything to kill.  However, as soon as you start growing your bacteria, plants or add fish, you should do pH adjustments to top up water in a separate tank and aerate it and let it settle before you add it to your system.

Drawback with Lemon (citric acid) is that it has antibacterial qualities that can cause problems cycling up a new system.  Vinegar doesn't seem to have as long lasting effects (it breaks down) so you need quite a lot of it to counteract the carbonates.

Muratic acid tends to be long lasting and effective but keep in mind that the chemistry will break up things like calcium carbonate, the carbonates will get used up counteracting the acid and the remaining calcium and chloride will combine to form calcium chloride which is a salt.  (If you are constantly needing to use lots of acid all the time to keep your pH down, you may find issues with higher TDS and some things like strawberries might not like it.)  Collect rain water or use some RO water so you are not constantly having to use acid.

You do want some minimal amount of hardness in your system water since it will help buffer and keep the pH from getting too unstable and crashing too low.

I have used phosphoric acid but be careful when using phosphoric acid in a system near the time you also dose chelated iron or you might cause a bit of a snail die off (which might cause you to need to clean snails out/off your pump to keep from clogging it and restricting flow.

[Mike Creuzer]

I want to thumbs up or pin, or somehow mark this as the best answer.

TCLynx said:

[great stuff]