How To Increase Aquarium pH – Naturally! 9

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As a follow up to my previous post 4 Simple Ways to Lower Aquarium pH Naturally, I’m writing this article to help you understand why pH levels of your water suddenly dip and how to increase it to normal levels – naturally.

Yes, it happens to almost all home aquaria owners. You thought everything’s fine and all your little water pals are happy and comfy, and the next day, you see them all lank and weak.

So you scramble to check on the water’s pH and, you guessed it right, the pH level slid down to a dangerously low scale.

Maintaining a balanced pH in your aquarium is very important in order to maintain a healthy environment in your tank.

Natural biological changes in your tank cause the pH to decrease over time, like unconsumed fish food or decaying organic matter, so you really need to constantly check the pH level and make the necessary adjustments if needed, including having to raise the pH.

And like what I’ve said before, I’m not exactly a fan of chemicals to raise pH level because with chemicals, it’s difficult to gauge whether you’re putting too much of it which may result in the drastic change in the pH of the aquarium.

Altering the water’s pH too rapidly may result in a disaster. You wouldn’t want to see your hard work going down the drain.

So better be sure than sorry. Don’t opt for the quick fix solution. The natural way is still the best way, and there are a lot of natural methods you can do to raise pH level.

Here are my top 4 natural methods to increase your aquarium pH:

1. Add crushed corals

Coral skeletons, and even most shells of molluscs, generally contain calcium carbonate which naturally increases pH. Crushed corals can be easily bought in any local fish store.

The best way to use crushed corals is to add it to your filter. At the start, you may use two to three small filter bags for your tank. This way, you can easily adjust the volume of crushed coral you want to put in your aquarium.

Crushed Coral - Increase pH

Adding crushed coral to your filter – Pix Source: Tropical Fish Keeping

If the pH level becomes too high, then you can easily remove one or two bags to decrease pH. Another way to use crushed coral is to simply get a handful and drop them at the base of your tank.

Remember, though, that the effect of crushed coral to your aquarium’s pH is gradual and you will have to wait for some hours before you notice the pH slowly rising.

2. Add dolomite chippings to your filter

You may have seen those multi-colored gravels that look really nice when they’re in the water. Well, they are there not just for aesthetic but to increase pH as well.

These kinds of stones which have rough texture with powdery coating are made of dolomite. A dolomite is a kind of mineral that naturally transforms into a stone or gravel over time. It is rich in calcium and magnesium.

Dolomite Aquarium pH

Dolomite can also be used as substrate – Pix Souce: 3Reef

White dolomite chippings are usually sold in local fish stores for use in marine or saltwater tanks to stabilize pH and alkalinity.

The best way to use dolomite chippings to raise your tank’s pH is to add them to you filter. But then you’ll get some cleaning issues because it is quite difficult to clean the filter full of chippings.

One effective way is to use gravel cleaners that are syphon-powered to make the chippings swirl around and suck the dirt out.

3. Use limestone (calcerous rocks)

Limestone is a kind of calcerous rock that contain high levels of calcium carbonate so they are really ideal for increasing pH for either saltwater or freshwater aquariums.

While these are generally used for landscaping and can be found in construction stores, limestone is a great way to cheaply and effectively stabilize the pH is your tank.

A popular type of limestone generally used to decorate the aquarium, but is actually there as pH stabilizer, is the “Texas Holy Rock”. The natural holes and ‘cave-like’ formations of this limestone are favourite hiding places for fish like catfish or cichlids.


Texas Holy Rock provides hiding places too

But use limestone sparingly. You don’t want to overcrowd your tank, and more importantly, court the risk of making your aquarium’s pH too high for your fish. Try putting in two medium-sized limestones and observe how it affects the pH.

There are also other types of calcerous rocks that help increase water pH, including Aragonite, Tuffa, Oolite, Travertine, and Dolomite (which I mentioned earlier).

Since they are cheaper, they’re a good option for naturally keeping pH at a balanced level. But make sure you don’t dump large amounts of the stones into the tank. Put in a small amount first, then test for pH, and do this until you get the ideal pH level.

4. Marcroalgae

Growing macro algae in your home aquarium has a lot of benefits, and one of them is keeping the water’s pH at a stable level. Macro algae absorb harmful carbon dioxide as they grow even as they make your tank great-looking and provide a simulated underwater environment your water species love.

What macro algae do to increase pH is to naturally co-exist with the other species and compete with other nuisance algae in the tank. It also naturally produces dissolved oxygen that circulates in your tank, making the water healthier for all the water creatures there.

Macro Algae

Caulerpa Taxilfolia a common type of macro algae – Pix Source:

Growing macro algae is the best and cheapest option for people who are just starting up with their home aquarium. It is more simple to do and less tedious than growing corals.

Macro algae are known to survive without too much maintenance and they can handle changes in the environment or even water temperature. They don’t even need any sophisticated lighting because they can thrive even with lower lighting. To learn more about algae control, read here.

Macro algae are thus better than coral as far as sustainability is concerned. And, what’s even better about them is that they supply not only the food for many of your little species, but the minerals the water needs for the ideal pH quality as well.

Your Experience

Have you had any experience in raising the pH in your tank naturally? Did you use any of the methods mentioned above?

Share your tips and experiences in the comments section below.

About Dennis Hanson

Dennis is an experienced aquarist with many years of knowledge and experience in keeping successful tanks. He also has no relations to the pop group Hanson.

9 thoughts on “How To Increase Aquarium pH – Naturally!

  1. Reply Ryan Sep 1,2014 8:39 am

    Hello. I was reading up on how to raise the Ph level in my aquarium (I am trying to start a self-replenishing triops colony, and they require at least 7-8 on the Ph scale) because I tried a commercial product called “Correct Ph, from the “Jungle” brand, and it did not change the level one bit. I am using calcium carbonate sand, which, if I read your article correctly, is supposed to raise the Ph anyway. However, I tested the water and found I indeed needed to raise the Ph some other way. Do I just need to give the sand time to affect the water?

    Also, I noticed an extra “r” in the “macroalgae” header. 🙂

  2. Pingback: Safe ways to raise pH, hardness - Newt and Salamander Forum

  3. Reply Pete Oct 9,2015 3:47 pm

    This was very helpful. Crushed coral in the filter fixed my soft water from the tap issue. Do you have a suggestion on how to prep my water change containers to increase the hardness, so that I don’t reduce the hardness each time I add water?

  4. Reply Joni Solis Nov 7,2015 10:49 pm

    Thanks for posting this article. I have well water and it is very soft with a low PH. I want to increase the kH of the water. I have added a couple of pieces of Texas Holey Rock and I bought some crushed oyster shells. But if one is using a sponge filter and not an hang on the back filter where would you put the crushed oyster shells? Also like Pete I am also wondering how to prep water for a water change so as to not shock fish with a pH change when doing it. Thanks!

  5. Reply Bob Apr 23,2016 9:21 pm

    I have been using crushed coral for sometime now, in all my tanks. 125, 55, & 45 gallons. In each tank I have Shubunkins. Lately I’ve noticed that the fish in the 125 gallon appears to be sluggish. I did a little research and someone suggested using Prime in my tanks also. Not wanting to overkill, has anyone tried using PRIME, with the CRUSHED CORAL?

  6. Reply Sharen May 2,2016 8:25 am

    Tried PH Up but pet shop said that aquarium salt is cheaper so for my 10 gallon tank dissolved 1 teaspoon in warm water until all dissolved and put into tank. Every time I now do a water change only put in about 1/5 of teaspoon as salt does not evaporate and too much salt is a bad thing. Also had some small shells which I washed and crushed and then put into tank. The fish are all happy even the new black mollies are doing well.

  7. Reply Amelia Jul 12,2016 2:40 pm

    I have two goldfish (Enya & Rhydian) and I currently the water is at 6.3 and i have been using ammonia Rocks trying to raise it to 7 but I’m having trouble doing that and my fish are quite stressed. The water was good until I went away and now it’s too low and I can’t seem to get it back to 7. Is there anything I can buy to raise other then coral or lime stone? I hear something aquarium salt but I don’t know what the effects are if I’m already using ammonia rocks.

  8. Reply StevenDon Jul 14,2017 7:28 am

    Thanks for this article, it’s very helpful, especially for the novice.

    Another option is shell grit. It’s almost like sand and does a good job.
    In regard to additives like pH up or bicarb of soda, they will raise the pH too quickly and potentially harmful the fish. Another thing that some may not know is that’s each number on the pH scale is a factor of 10, so lifting the level from 6 to 7 is 10 points, but lifting the level front 5 to 7 is 100 points. Knowing this makes it easier to understand how much harm raising, or lowering the pH too much and too quickly.
    Another point worth mentioning is that aquarium salt and the water conditioners which is basically salt with additives is harmful for scaleless fish such as cats, bristlenoses, clown loaches and a lot of others. They don’t like the salt and will get very sick if salt is used in their water.
    Another thing for novices to understand is how kh and gh effect pH. And also different fish require different pH levels. African Cichlids like their pH around 8 whereas some others like their pH around 6ish. One of my tanks which is heavily planted and has micro fish and shrimp has Co2 running during the day but not at night. The pH naturally fluctuates from around 6 when the Co2 is running and up to high 6 at night when the Co2 is off. The pH fluctuates slowly and the inhabitants are very healthy and happy. A lot to learn for the novices, and even for the experienced alike.

  9. Reply Lewis Oct 25,2018 4:52 pm


    I have African cichlids from a soda lake which is naturally pH 9-10.5, the pH of my system is currently around 8.6 and I am struggling to raise it to the natural pH of the fish.

    Does anyone have any suggestions to get the pH up?

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