How can I lower my pH, which is at a high 8.4?

[Nitro]

The pH of my tap water has always been 8.4. I've called the local water supplier and they say pH ranges from 8-8.8 in my area. I tested it myself and got 8.4 and went to PetsMart and got 8.4.

I want to know to lower pH without harming fish or using those crappy
"Proper pH 7.0" or "pH down" chemicals.

I heard to use peat balls or moss but I don't want my water looking like tea.

I have two pieces of driftwood in the tank already and doesn't seem to make a difference.

I also have a high KH and I'm confused what the "buffering" is.

Water parameters:
pH: 8.4
KH: >300 ppm
GH: 25 ppm

Ammo: 0
Nitrite: 0
Nitrate: 30

[TheOldSalt]

The Kh buffering hardness is what keeps you from being able to lower the pH. It's the karbonate hardness ( kh ). Very simplified, when the pH tries to drop, the calcium/magnesium carbonate in the water reacts with the things doing the dropping, nullifying their effect. Over time your Kh gets used up by this, and then your pH starts to drop like crazy.
What you need to do is reduce your Kh. Once it's down, your pH can come down to match.
There are chemical carbonate reducers you can buy, or use an ion exchange resin bag in your filter, or you can change half your water with distilled water ( which instantly drops your Kh in half and also lowers the pH ) , or yes, you can add peat to your filter, as peat does the ion exchange thing, stealing your karbonate.

[Nitro]

Can you please tell me EXACTLY how I would do this, like step-by-step because I heard rapid changes in pH is very stressful for fish and could be lethal.

[pinetree]

My water parameters are very similar to your's and I just leave it alone. Most fish tolerate it just fine, although if you're trying to keep and breed lower pH fish it would probably be a problem. African cichlids do particularly well in this kind of water.

[Nitro]

I'm not breeding fish. I thought their ideal pH (6.2-7.0) would better their growth, colors, etc.

Do you mind telling me your parameters please pinetree?

TheOldSalt, if I were to lower my KH in my aquarium, wouldn't a water change from the tap make the KH go up again? The KH in my tap is probably >300 ppm too.

[emc7]

What do you want to keep? When I had water like yours, I stuck to African cichlids and livebearers and they thrived. The "all fish need 7.0" is a myth created by idiots at stores who want all their fish in the same water.

If you do want to lower pH and kH long-term, it will take time and money. You should get a good method of testing both. At least a liquid test and maybe an electric meter.

Dilution or your tap water w/ RO or distilled or rainwater is a good solution, but it is a long-term commitment as you have to blend it in every water change.

If you have fish in the tank, you want to change any parameters slowly.

[pinetree]

My pH = 8.4
GH = 22
KH = 250ppm

Unfortunately, it is easier to raise those numbers than to lower them. I keep two large oranda goldfish and they're happy in my water. Perhaps if you post the type of fish you are keeping or plan to keep, people can advise you if your tap water would be an issue or not. I think it is generally better to keep your water stable and consistent, rather than try to alter it's chemistry and stress the fish with fluctuations.

[Nitro]

I'm keeping Angelfish, platies and a BN pleco.

Would this tap water affect them in any way?

I also have a Java Fern and an Anubius plant if that makes any difference.

[emc7]

angels and plecos like softer water. They can live and grow in hard, but may not breed successfully, but for soft-water fish, they are pretty tolerant. Platies will love your water. Java fern will also do fine.
If your tap is water kH is 300 (thats parts per million, so this is concentration math), your tank is likely 300 ppm. If you change water with 300 ppm tap, it will stay about the same.

If you replace tank water 10% with RO water, it will go down 270 ppm. But if you change water with tap it will go up again.

If you don't change water and "top off" evaporation with tap, the kH will climb. The minerals don't evaporate. If you top off with RO water, the tank should stay around 300. ppm. But if you don't change water, nitrate will creep up over time.

But driftwood and peat drops it. Limestone and crushed coral and the like raise it.

High hardness will resist a change in the pH.

Nitrate is acidic.

Acids like nitrate and pH lowering drops will 'consume the buffering capacity' until it is "used up" and then your pH can drop suddenly.

There are buffering products on the market. Things like SeaChem's acid regulator, acid buffer and Proper pH. In part, they work by removing carbonate from solution. Do not be surprised if the precipitate produced "snows" in the tank and covers stuff with a white powder. Use any product with great care and ease into it with increasing dosage slowly. Don't freak if the water clouds like milk, the fish usually are fine.

Adjusting water chemistry is long-term commitment, you have to make adjustments every water change and watch parameters in between and a miscalculation can kill fish.

Dilution is cheaper for a small tank. You could do a 20% water change in a 10 g with 1 g of tap and 1 g of store bought distilled water or captured rainwater. People who want to dilute water in large or multiple tanks usually buy RO units. They are pricey upfront and there is ongoing cost for replacing the ion exchange resin periodically.

[emc7]

My recommendation would be to top off with distilled or rain (put a bucket outside) water and change water with tap. This should keep things fairly constant and keep it from getting higher.

Keep an eye on nitrate, don't let it get any higher. Use water changes to keep it down under 20 (10 would be better)

Watch the fish, see if they are eating and acting normally. See how they do for a few months.

When your angels or plecoes start breeding revisit the issue.

In the mean time read up on the subject.

[Fishpunk]

RO water is how you lower the hardness and pH reliably. The best fishkeeping practice is to select fish that match your water. Matching your water to the fish is a lot more work.