DIY co2 and PH changes

[vequalsir]

How far does a co2 injected tank swing in ph? What can I expect?

I started a DIY co2 set-up yesterday. My initial ph was 7.4 with a kh of 6.

This morning my ph dropped to 6.4 and the kh is still at 6. Tested with an API test set.

I know that the co2 will increase acidity of my water, but I did not think I'd see such a big change. Just wanted to see if it's normal.

My DIY set-up is not optimal according to what I've read here and other websites.

I'm using a sealed milk jug to ferment. The gas is being fed to an air stone at the rear of tank somewhat near my HOB filter.

[shawnhu]

What size tank? A milk jug is usually 1 gallon, enough to supply 20 gallons+

You might be overdosing, keep an eye on the fish. Pictures of the bubbles would also help.

According to this calculator, your CO2 PPM might be at 71.6, way over.

[KarlTh]

Those figures do indicate that the pH/KH/CO2 table isn't far off so I'd be concerned the levels are rather high. Might just be the pH test being less than reliable though.

[vequalsir]

The pH test is new, but I'd rather believe my ph test is off.

this is a 28gallon tank. How could I have that big of a swing an not see a kh change?

[vequalsir]

what can cause my kh/ph ratio to be off? My initial reading even before adding co2, show me to have 7.1ppm.

Something's fishy

[DoctaQ]

test your ph straight out of your tank without causing any shaking that might release co2
then shake the test tube
the difference is how much your co2 affects your ph

[Turbosaurus]

Phosphates are a buffer also and will serve to lower your pH. Did you also fertilize the tank recently? What about drift wood? Tannins are natural organic acids. Either will skew the pH/KH chart.

And if you tested first thing in the AM, remember that both your DIY CO2 AND your plants both expel CO2 into the tank during lights out.

[KarlTh]

The pH test is new, but I'd rather believe my ph test is off.

this is a 28gallon tank. How could I have that big of a swing an not see a kh change?

Because the CO2 causes the depression in pH without changing the bicarbonate concentration.

[avionics30]

With a Kh of 6, you want your Ph right around 7.0. Inject CO2 until your Ph is at 7.0 and you'll be fine. Anything more and you are approaching too high a CO2 saturation.

[DoctaQ]

i think phosphate buffers are not good for planted tanks because it might cause an algae bloom with all of the light and nutrients around. i think seachem has an alkalinity buffer that does not have that problem, but i figure that your concern here is probably the concentration of co2 in your tank
i gotta say with an HOB filter and DIY there is very little chance that you can overdose your tank on CO2 because of low amount of co2 being produced and high amount of surface agitation.
i would beleive that your KH testing method is probably off and your KH is actually much lower than you think

[jmhart]

It's nearly impossible to overdose with DIY co2. Forget the gh/KH table, like Turbosaurus said...there's so many other things going on that it's unreliable.

How are your fish? Are they acting normally? If so, you're good. If not, then let's talk.

[shawnhu]

I'm overdosing my 10G with 1L of DIY yeast. I have it hooked up with a Red Sea wood air-stone. I need to turn on the air-pump once in a while to reduce it from yellowish-green to green.

[jmhart]

I'm overdosing my 10G with 1L of DIY yeast. I have it hooked up with a Red Sea wood air-stone. I need to turn on the air-pump once in a while to reduce it from yellowish-green to green.

A) are you using 4 dkH solution in your drop checker


and B) even if you are, how do you *know* you are "overdosing"?

If your fish are healthy/behaving normally, that's what matters.

[rocker92]

What size tank? A milk jug is usually 1 gallon, enough to supply 20 gallons+

You might be overdosing, keep an eye on the fish. Pictures of the bubbles would also help.

According to this calculator, your CO2 PPM might be at 71.6, way over.

where is this calculator you keep talking about????

[KarlTh]

The fact that the pH is dropping by an entire point shows that a considerable quantity of CO2 is going into the tank. I have also managed to OD with DIY, despite the scepticism of some on here. My pH dropped over a point and the fish went very dark, subdued and breathing very fast. Within a couple of hours of raising the filter outflow and removing the CO2, they were fine.

[Cluunox]

here is a calculator with a good atricle.
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

also a downloadable calculator for personal use on that site somewhere