I have a 180 litre planted aquarium maturing for Altum Angelfish. My pH is currently at 7.5, nitrate 10ppm and nitrite and ammonia levels are at 0. I would like to bring the pH down to about 6.0 or 6.5 to make it a more suitable environment for the Altums. I see a few phosphate buffers on the market but I am afraid they will do damage to my plants. What other ways can I bring the pH down without using chemicals?

There are a couple of ways to reduce the pH of your aquarium without the use of additives. The first is CO₂, which will also be beneficial to your plants while achieving your pH goals. A lot of our customers are afraid of CO₂ at first but it is very easy to set up, safe and cost-effective. The CO₂ will have a downward pressure on the pH of your aquariums water. In fact, the methodology takes into account your aquariums volume and KH so by sticking to these simple guidelines you can control your pH very easily, not to mention your plants will look great.

Proper regulation of CO₂ can give you control over your pH levels

Another way to bring your pH down is with the use of aquatic botanicals. Botanicals release tannic acids into the aquarium water which will help lower your pH and soften the water. The tannins will make the water a rich red or brown colour emulating the Altums natural environment. 

There are many types of aquatic botanicals you can introduce into the aquarium each releasing various degrees of tannins. Therefore you can have a little control over the colouration of the aquarium water. For example, adding Catappa leaves to the aquarium would turn your water deep red as they produce copious amounts of tannins. However, introducing aquatic botanicals like logan leaves which do not produce as many tannins as Catappa leaves would turn the water a golden yellow tone. Aquatic botanicals are also said to provide additional benefits such as boost health and intensify colours. You will also find your Altum angels will thrive more in a blackwater environment.

Pterophyllum altum thriving in a tannin rich South American biotope

So, you have two options to lower your pH without the use of phosphates and chemicals. You can go all-natural and create an alluring tannin-rich South American biotope or a beautiful lush planted aquarium. However, do not cross the two over. CO₂ mixed with the release of tannins will make the pH very unstable resulting in a pH crash, which can be detrimental to the inhabitants.   

Want to create a tannin-rich blackwater aquarium? Check out our natural hardscape.