How to Rise Your Reef Tank's pH?

What exactly is pH? And if it is low what can be done to raise it? All your queries related to pH in your aquarium is covered up here in this article (as described by ReefDudes):

What is pH?

Before getting into all the technicalities of pH in your tank, it is important to understand what exactly is pH. Scientifically speaking, pH is technical log measurement, but we just want to understand it in the prospect of our aquarium. Therefore in a simplified version, pH is the measurement of the relative concentration of Hydroxide ions and Hydroxyl ions.

The measurement essentially tells us if our pH is acidic or alkaline. A pH of 7 is considered neutral above seven is alkaline and below seven is acidic. 

So, pH is tied to carbon dioxide and alkalinity levels near the aquarium. As CO2 interest the water, it will make the water more acidic which in turn lowers your pH.

What Can Lower Tank's pH?

A few other things that can affect this is if your house is having a lot of content, maybe because of lots of people and pets in the house which will be adding more COto the atmosphere. This will be creating a higher concentration of COin the air which is going to make its way into the aquarium and hence lower your tank's pH.

Way to Rise the pH

Natural Oxygen

One of the first and easiest thing you can do is open with windows in your house. By releasing ore of the CO2 out of your house, you will be having a higher concentration of oxygen with lower CO2 and that in midterm will be absorbed into your tank. This alone can greatly boost your pH.

When your lights are on, your corals and other things in the tank slows the synthesizing process which is slowing done the absorbing process in the tank, but at night time this process is not happening. So, a lot of people like to run refugium which kind of macro-algae jeido in the reverse cycle.

So there are lights in your Sump which turns on when you display tank turns off so there is always photosynthesis going on. Though this will not be raising your pH a lot, for the most part, you are keeping it more stable instead of having ups and downs.

Surface Agitation

Take your powerheads and point them more towards the surface of your tank which will cause more rippling and thus more gas exchange. Another thing you can do is use an air bubbler or wooden Sersol inside your pump. This can create little micro bubbles indie you pump again injecting oxygen.

While using this method you want to make sure that the air pumps are outside so that you are pulling more fresh air into it. You can also take your air bubbler and run the holes outside of your house, but this will only work if your tank is close to the outside wall.

You can drill a little hole in the wall and you run an airline in, you can either run it into your air pump and then turn your air bubbler in the top or you can run directly into your skimmer intake. Wither one of these are going to have a huge boost on pH. 


You can use Kalkwasser in your tank. It has a pH of 11-12, so if you drip that in it is going to slow up your pH. If you are doing other dosing means then this may or may not work for you. Having a calcium reactor can also lower your pH.

Since you already have such a low pH coming out of the tank, you are injecting CO2 into the chamber and that is turn is dissolved with the coral's skeleton and that will be lowering your CO2. 

You can also use a second chamber which in turn will help raise the pH, it will give that acidic water more dwell time with the coral skeleton which will help absorb it and raise the pH. If you want quick results you can put air stone into it and it will eventually help achieve your desired pH level.

Canopy Tank

If you have a Canopy tank, you can put a PC fan in the Canopy and it blowing through. This will just bring that fresh air into the tank, rather than being ina close environment you can do a similar thing in your Pump. 

Some store sells pH buffer, it might solve your problem but that is a temporary thing and will not help in the long run. So, do avoid those.

What is the Acceptable pH of the Tank?

For a saltwater tank, anywhere from 7.6-8.9 is an acceptable range, but an ideal range would be 8.0-8.3. Though it is not necessarily something that you need to do, if your fishes are happy and your corals are growing good, at a little lower than the ideal range, you are fine.

Assuming your tank is in equilibrium with CO2 and the outside air meaning that is not going to affect the pH disturbance anymore; alkalinity will determine your pH to an extent. So, if you have higher alkalinity, it essentially buffers it and allows you to have a higher pH.

One of the biggest things is a reef tank to keep things happy is keeping it stable. So, you ultimately want to keep your alkalinity stable all the time every day, you never want to have big swings because this will stress your corals and cause more harm than good.


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