pH controller

[Clare]

My CO2 controller is on a timer. It comes on two hours before the light cycle and turns off an hour before it ends.

Like I said there really is no reason to run the controller at night. Let's take my tank as an example. During the CO2 period the tank is at a pH of 4.85. Once the CO2 controller is turned off near the end of the lighting period the pH begins to rise. By the time the CO2 come back on in the later morning it's at about 5.90 or so. If my CO2 controller were running at night my pH would remain at about 4.85 all night and I would be injecting CO2 all night long, which is a waste as plants are not using CO2 at night.


Crazy pH swings are pretty much a myth. pH crashes are almost always tied to poor maintenance. Most of the best planted tanks in the world run very little to zero dKH. Plants prefer it. Most livestock doesn't care. It's an old myth but it dies hard. At beginner sites you will often see the irrational fear of low pH and pH crashes. They have fear because of what they have read not what they have experienced.

Here's a link to a good article about low pH tanks by my friend the 2hr aquarist. My tank is shown there when my dKH was at 1.00. Since then have been running it at zero for several years now.

Are bacteria affected due to low pH/KH in aquasoil tanks?

Does the low pH caused by CO2 injection or aquasoil affect livestock or bacteria in the planted aquarium? Should I use buffers to raise the pH?

www.2hraquarist.com

Thanks for this, very interesting.

 

[Clare]

You are correct. The higher KH minimizes the "crazy swings". The point is not merely to avoid dangerous levels, but to tame the transients so that the pH response will not be choppy. Fully automated means turning the solenoid on and off in response to crossing back and forth across a programmed threshold value. You will get transients. A reasonable amount of buffer resists pH change, thus providing a "cushion" to absorb sudden drops upon turn-on. A higher base-line KH value enables you to obtain a stable CO2 concentration at a comfortable pH. A dKH of at least 4 gives you some room to program a sane and sensible pH. You get still more room with 5. Testing and adjusting KH is really easy to do.

I am not pushing anything here, so do not construe my remarks as advice. I am showing that a full-auto CO2 system is possible and does work. But it is a specific methodology with protocols. If you trust your pH monitor, you don't need to consult a drop checker. With a very good quality needle valve you won't need the drop checker or the bubble counter. You will need to keep the pH probe clean and to check its calibration occasionally. This is an alternative method. Each method has its rules. Its largely a question of what rules you want to go by and in which equipment line-up you want to place your trust.

I like your aquascape. The wood is impressive.

Thank you for this info.
And thanks re wood….I confess I did spend a bit of $$ on it!

 

[Clare]

Along with “Dirty Tank Syndrome”, I’ve also heard the origins of the “pH crash” came from a beginner’s understanding of the interaction between carbonates, general hardness, and pH. Let’s look at this from the perspective of a non-plated tank fish novice…

Our Fauna become acclimated to a particular GH, and that number represents the osmotic pressures being put on each and every cell in their body. Taking a fish from dGH 15 water and plunking them into a 5 dGH tank will almost certainly result in the death of the fish. Now, when we’re talking municipal water, or groundwater in a particular location, it’s assumed that they’re going to have similar GH values between the fish store and the home tank.

Expounding from there, typical municipal or well water will also contain a specific amount of carbonate in the water, affecting the pH. What we normally see is an increase in GH will also present with an increase in KH. This isn’t true 100% of the time, but it’s good enough for the average aquarist.

From the fish-only world, and especially novice aquarists, water testing is a big taboo. They should be familiar with ammonia, nitrite, and nitrate testing, but that’s about it. When their fish suddenly die, the fish store will have them do a pH test to see what their pH is registering. The average fish store employee knows that water with drastically different pH **can** kill fish, but they don’t really know the **why**. It’s just assumed that the cause of fish distress is due to the pH.

The actual cause of death in these cases, where fish are put into water with a drastically different pH, isn’t the pH, or the KH of the water. It’s the GH of the water. A lack (or over abundance) of Calcium and Magnesium ions will affect the osmotic pressure of the livestock, and a sharp change can kill your fish.

The anecdote of the “ph crash” happens when a municipal water supply drastically changes the general hardness of their water. Aquarists don’t know what’s happening, go to the fish store, get told to check the pH, and come back with a very low pH (remember, GH and KH almost always go hand-in-hand). The fish death is blamed on a pH crash.

I have to say chaps, I wasn’t thinking that deeply about it!
….when I wrote “crazy swings” I probably overstated my concerns. Rather than referring to pH “crashes” I had just meant the pH high and lows during the 24hr period, between CO2 on and CO2 off…

…..somewhere or other I’d read that a wide variation can encourage algae, (or effect livestock) but I have no idea what that mechanism would be.

(Re the information you’ve provided….Given homestasis in the healthy human body maintains pH between 7.35-7.45 to allow best enzymatic functioning, it’s pretty impressive that the thin walled bacterium can function in such a wide pH range! Pretty cool!)