Controlling Your pH

It seems as though this weeks theme may actually be talking about your pH. That’s per hydrogen, not pretty hottie!

Just like your own bodies pH, it is important to know how to monitor it, change it, and control it. Yesterday’s article proved that little things such as light bulbs can adversley affect the parameter. So lets take a look at things that can change and things that you can do to control your water’s pH.

Carbon Dioxide (CO2) – Found in air, and in your water. A big part of the photosynthesis equation (seen here). Used in calcium reactors to dissolve calcium media by lowering the pH (making the water more acidic). Too much in your tank’s water, both fish and corals suffocate. It is the main factor in the changes in your pH.

Alkalinity (meq/L, or dkH) – A measure of how your water can neutralize acids to the equivalence point of carbonate or bicarbonate. In this instance, alkalinity is positively correlated with the pH of your tank’s water. The more is added (alkalinity buffer), the higher it (pH) gets. And vice versa.

Photosynthesis – Many corals (autotrophs), and all algae go through this process. The consumption (lowering) of CO2 in water through photosynthesizing helps balance the pH in aquaria. As seen in yesterday’s article, corals/algae gain energy and thus, consume more of CO2, release oxygen, and on, on (kind of like a vicious cycle, but in a positive way).

Aeration – Water turbulence or surface agitation provides much needed gas exchange between the air outside the tank, and the gases inside the water. The CO2 gases need to be equalized with the air outside (containing O2, CO2, and other gases) to regain a stable pH reading. If your air already has high concentrations of CO2, then you need to find a way to increase air exchange between the inside and outside of your house. As always, the outside air has much higher concentrations of O2 than, for example, your basement air.

Calcium Reactor – There are many improperly setup reactors in this hobby. Many of them use a single chamber to supply their needed calcium/alkalinity. As their tank’s needs increase, so does their drip rate. A recipe for a disaster, especially having 6.4 pH water displeasing 7.8 pH. A way to neutralize this swing in pH is to succeed the first chamber with another, filled with aragonite media. As the water travels, its pH regains a more neutral value, enabling you to drip much faster without any worry.

Randy Holmes-Farley, an accredited man of science and my favorite reefy chemist, wrote an article in 2004 showing how pH can have different effects on your tank’s parameters. What struck me was how we can move the pH up and down by just a little human influence. The graphs summarized everything, take a look: