Ways to lower water ph

[Mikeyboy123]

You can't change your water...without changing your water.

If your tap water is pH 8.2 then it is likely pretty hard as well. Peat pellets, oak leaves etc aren't really going to do much because the water is likely highly buffered. I've never used water softening pillows and the like so can't comment.

What you need to do is dilute your hardness down with another water source such as RO or rain water.

I live in London and so my tap water is pretty hard and alkaline. I mix it with rainwater and then prefilter overnight with Polyfilter before doing a water change. I experimented with various ratios and have settled on a 3.75rain:1tap ratio which reduces my hardness down to GH6, KH4. I then find that the tank pH stabilises out at 6.8 with the aid of a few alder cones, oak leaves and a large catappa leaf.

I'm happy with this as it's in the range where my chili rasboras, nerite snails, pygmy corys and cherry shrimp are happy, and I don't want to go too soft as I am wary of risking a pH crash in water that has very little buffering capacity.

It's pretty easy for me to do with the small volumes I'm using for my two nano tanks, but no reason it couldn't be scaled up for larger volumes.

 

[TwoTankAmin]

You cannot lower pH in a consistent and stable way unless you can manipulate KH and often even GH to some extent.

I make my own RO/DI water. I normally use about 23 gals. every 2 weeks. If I have a special situation (like doing a dry/rainy season to trigger spawning) I may need to make an extra 50 gals. to do the rainy season.

I have owned a portable 3-Stage unit- Carbon->RO->Deionizing Resin = very close to pure water. This should be neutral pH and 0 KH and GH and pretty much anything else. In fact this is not the case. For example, there is oxygen and CO2 dissolved in water. CO2 in water creates some carbonic acid and that, in the absence of KH, causes the pH to drop clearly below 7.0.

So what is my point here? My unit, with a 75 gpd membrane in the RO was purchased over 10 years ago, I have replaced both the carbon and RO segments but not the DI one (It is overdue I think). I originally paid about $125 for it delivered and before online vendors charged you sales tax.. Today is sells for $139 + shipping + your local sales tax, if any.

In the most recent past I was also making the "pure water" for my brother because he had been buying distilled at about $1/gal. for a pair of small humidifiers which he ran in the winter when the air is dry and heaters are going as well. So for about 4 months of the year I was making about 18 gal. every week for him.

So if I add the cost of my two replacement modules which was about $60 delivered, it makes my total cost $185 over the. I made for myself 21 gal./2 weeks for the first few years. Then I told my brother to get his own unit. So now we have two. He had to spend more like $155 delivered. I batch our water year round and alternate between the two units. It is important not to allow the RO membrane to dry out. The second unit wont need replacement modules for as much as 2 more years and we got it about 2 years ago.

I cannot estimate my cost per gallon because it has been a long trail to here, But I would guess is it under 20 cents a gallon and likely way less. We batch water and store it in a lot of gallon jugs plus I use 3x5 gal. buckets, a 6 gal. water can and a 2.5 gal, gas can (never used for anything but my RO/DI water). This way we usually only run the units once every 3-4 weeks and we make about 45 - 90 gals each time. depending on the season and a few other factors.

When I do weekend events I bring my RO/DI unit and can usually hook up to almost any tap. But at the Catfish convention last Oct. the hotel changed the plumbing and it was impossible for me to connet to a tap. I tried using a pump and bucket, but it was not strong enough. So I needed 25 gals of pure water and I had to make a run to a local sypermarket. I got lucky and the distilled was on sale at 90 cents/gal. so I spent almost $23.

At the normalish $1/gal. price, I I could have bought both RO/DI units and the two replacement carts for about
$340. That would buy us 340 gals of distilled. I have batched at least 4,000 gals. with the two units. And I expect they will do a few 1,000 more before its time to get some new modules.

One can buy a units in all sorts of configurations depending on one's needs. If you need less water then a 50 gpd may be enough. And folks with big needs can spend up and get units with much higher outputs. You can get portables like I use or permanently plumbed units which do not get moved.

The one thing I do know is that it is much cheaper over time to make your own"purer" water rather than buying it by the gallon. For what it is worth, here is where we got our units. The do it all in terms of outputs https://store.afwfilters.com/water-softeners/

 

[Magnum Man]

Some may find this interesting… some not

I have an aquaculture set up outside, along the back of my house… there is no evetrough on the garage, where the tanks are, so when / if it rains, I get a fair amount of rain water blended in my tanks… which by design, allows water to overflow… it’s been really dry lately, but we’ve had an inch and a half of rain, in the last 2 days… I just tested my water ( sorry, hard to calculate how much rain water got into the tanks) but my alkalinity dropped from a Max on my test strips of 300, down to 180 on todays test, yet my PH remained on the max my test strips test of 8.4… so the rain water dropped my alkalinity, yet my PH remained the same… water parameters are fine for the Tilapia, but the rainwater didn’t change my tank readings

 

[TwoTankAmin]

It is not quite that simple. One can convert between ppm and dh by using a multiple of 17.8 ppm/1 dh. So at 180 you still had 10 dh. To drop the pH you would have needed more rain water. And the readings that changed and which you did not report any readings, would be GH which contributes to conductivity/TDS which also changed.

Buffering Capacity (KH, Alkalinity)​

Buffering capacity refers to water's ability to keep the pH stable as acids or bases are added. pH and buffering capacity are intertwined with one another; although one might think that adding equal volumes of an acid and neutral water would result in a pH halfway in between, this rarely happens in practice. If the water has sufficient buffering capacity, the buffering capacity can absorb and neutralize the added acid without significantly changing the pH. Conceptually, a buffer acts somewhat like a large sponge. As more acid is added, the ``sponge'' absorbs the acid without changing the pH much. The ``sponge's'' capacity is limited however; once the buffering capacity is used up, the pH changes more rapidly as acids are added.
Buffering has both positive and negative consequences. On the plus side, the nitrogen cycle produces nitric acid (nitrate). Without buffering, your tank's pH would drop over time (a bad thing). With sufficient buffering, the pH stays stable (a good thing). On the negative side, hard tap water often almost always has a large buffering capacity. If the pH of the water is too high for your fish, the buffering capacity makes it difficult to lower the pH to a more appropriate value. Naive attempts to change the pH of water usually fail because buffering effects are ignored.

In freshwater aquariums, most of water's buffering capacity is due to carbonates and bicarbonates. Thus, the terms ``carbonate hardness'' (KH), ``alkalinity'' and ``buffering capacity'' are used interchangeably. Although technically not the same things, they are equivalent in practice in the context of fishkeeping. Note: the term ``alkalinity'' should not be confused with the term ``alkaline''. Alkalinity refers to buffering, while alkaline refers to a solution that is a base (i.e., pH > 7).

How much buffering does your tank need? Most aquarium buffering capacity test kits actually measure KH. The larger the KH, the more resistant to pH changes your water will be. A tank's KH should be high enough to prevent large pH swings in your tank over time. If your KH is below roughly 4.5 dH, you should pay special attention to your tank's pH (e.g, test weekly, until you get a feel for how stable the pH is). This is ESPECIALLY important if you neglect to do frequent partial water changes. In particular, the nitrogen cycle creates a tendency for an established tank's pH to decrease over time. The exact amount of pH change depends on the quantity and rate of nitrates produced, as well as the KH. If your pH drops more than roughly two tenths of a point over a month, you should consider increasing the KH or performing partial water changes more frequently. KH doesn't affect fish directly, so there is no need to match fish species to a particular KH

Raising and Lowering pH​

One can raise or lower pH by adding chemicals. Because of buffering, however, the process is difficult to get right. Increasing or decreasing the pH (in a stable way) actually involves changing the KH. The most common approach is to add a buffer (in the previous section) whose equilibrium holds the pH at the desired value.
Muriatic (hydrochloric) acid can be used to reduce pH. Note that the exact quantity needed depends on the water's buffering capacity. In effect, you add enough acid to use up all the buffering capacity. Once this has been done, decreasing the pH is easy. However, it should be noted that the resultant lower-pH water has much less KH buffering than it did before, making it more susceptible to pH swings when (for instance) nitrate levels rise. Warning: It goes without saying that acids are VERY dangerous! Do not use this approach unless you know what you are doing, and you should treat the water BEFORE adding it to the aquarium.

Products such as ``pH-Down'' are often based on a phosphoric acid buffer. Phosphoric acid tends to keep the pH at roughly 6.5, depending on how much you use. Unfortunately, use of phosphoric acid has the BIG side effect of raising the phosphate level in your tank, stimulating algae growth. It is difficult to control algae growth in a tank with elevated phosphate levels. The only advantage over hydrochloric acid is that pH will be somewhat better buffered at its lower value.

One safe way to lower pH WITHOUT adjusting KH is to bubble CO2 (carbon dioxide) through the tank. The CO2 dissolves in water, and some of it forms carbonic acid. The formation of acid lowers the pH. Of course, in order for this approach to be practical, a steady source of CO2 bubbles (e.g. a CO2 tank) is needed to hold the pH in place. As soon as the CO2 is gone, the pH bounces back to its previous value.

both quotes from https://fins.actwin.com/mirror/begin-chem.html#altering

 

[Magnum Man]

so... I'll be blending in RO water into my tanks, starting that are currently quite hard, in 3 weeks to a month... I do 33% water changes every week to week & a half... I expect the 1st time ( with my waters natural buffering ) I likely won't see too much of a change, but there is likely to be a pretty big swing of things by the 2nd or 3rd, or 4th water change... ( I'll be testing a lot at this time... maybe even every 5 gallons of water exchanged, when I start running out my buffering ) I assume I'm not the only one who has been forced to do this ( add softer water to hard water tanks )... any ideas what I can expect??? my hard water fish tank, will still get tap water, but the tanks that have softer water fish, are the ones I want to mess with... & I assume at some point, I'll be adding back minerals from a supplement like

Amazon.com

www.amazon.com

BTW, the comments above about my Aquaculture set up, were really just demonstrating the buffering, if 10-20% rain water was added... I'm not trying to alter anything on that water, it's just right for the Tilapia

 

[Mikeyboy123]

so... I'll be blending in RO water into my tanks, starting that are currently quite hard, in 3 weeks to a month... I do 33% water changes every week to week & a half... I expect the 1st time ( with my waters natural buffering ) I likely won't see too much of a change, but there is likely to be a pretty big swing of things by the 2nd or 3rd, or 4th water change... ( I'll be testing a lot at this time... maybe even every 5 gallons of water exchanged, when I start running out my buffering ) I assume I'm not the only one who has been forced to do this ( add softer water to hard water tanks )... any ideas what I can expect??? my hard water fish tank, will still get tap water, but the tanks that have softer water fish, are the ones I want to mess with... & I assume at some point, I'll be adding back minerals from a supplement like

Amazon.com

www.amazon.com

BTW, the comments above about my Aquaculture set up, were really just demonstrating the buffering, if 10-20% rain water was added... I'm not trying to alter anything on that water, it's just right for the Tilapia

I understand your worry about transitioning from the current hard water to softer water and the effect that the fluctuation may have on your fish. It wasn't a concern for me as I sourced my fish from a supplier in a soft water area rather than an lfs, so I made sure I had reasonably soft water ready to receive them.

My only advice is to take it steady and gradually introduce the change. Maybe 33% per week is too abrupt. Maybe do smaller changes over a longer time period.

 

[seangee]

When I switched from rock hard tap water to RO I did a 20% change every day for a week. At the end of the week I did a 50% change and since then I do 75-80% weekly.

 

[Alice B]

I'm surprised the OP's angels are doing good... that's one of the fish I've been having trouble with... & I have been wanting to do a Discus tank, so that will only happen if I can figure this water out...

which is part of why I started this thread... my plan is here...

need info / suggestions for RO unit...

so my well water is very hard, & I'm trying to make my water more pleasant for each fish, thinking I'll need to blend some RO water during water changes until I reach my target parameters for each tank... then possibly add back some minerals down the road as needed... I currently have been...

www.fishforums.net

we have high pH in a lot of Texas, I know people that breed angels at 8.0 for sure.