CO2, KH, and PH confusion!

[CaptnIgnit]

Ok, so I have a long setup to all of this so bare with me.

Last week I recieved my XP1 and hooked it up. I put my DIY co2 reactor on the output of the filter which oriented it incorrectly, but I have been too lazy to change it. A side effect of this is that a bubble builds up inside the reactor and then, once it reaches critical size, a little floods out in tiny bubbles. I decided I liked this and would see what kind of affect it had on the CO2 production. Another benefit was that the new spray bar got rid of all of the surface movement so no CO2 would be lost.

btw, I have 2 2 liter bottles hooked up to my CO2 reactor.

After a few days I noticed everything was pearling like mad. I was very happy with the way it was working and decided to check the CO2 levels. It came back with a reading of KH: 9 and pH: 6.4, aka 107 ppm of co2! I immediately started freaking out and redid the reading but it stood. None of the fish looked affected by lack of oxygen so I was debating if it was right or not. I decided to do a water change incase something was added to cause a buffer.

I checked the day after and it was still in the 90's after the water change. So I checked the day after that (after checking on the fish at night to see if they showed signs of oxygen deprivation, none) and it showed the CO2 at around 54 ppm (pH 6.7) which I found more believable. But I noticed a fish had come down with a white spot (check the unhealthy fish section for more info on that). The next day I tested as well, and it came out as 96 ppm CO2.

At this point I decided to drop one of the 2 liter bottles and see what it would show up as. I tested tonight and it was at 26 ppm CO2 (normal amount I had previously with one CO2 bottle a few weeks back).

My questions are this:

1. First, my KH is normally around 6-7 and it jumped to 9 and stayed there even after a water change (which freaks me out that it is getting that high, my tap water has a KH of 2). Tonight it is at 9.5 and only seems to be increasing. Of what I have added, what do you suppose is increasing the KH so much? I believe a rock I have increases it a little, as the water gets more acidic, does that eat away more of the rock?

2. Do you suppose the fish disease is related to the CO2 being so high? It could be a number of things, but I am worried about keeping the 2nd bottle hooked up if the CO2 gets so high.

3. Any other suggestions on what I should do?

 

[MSU Fan]

I am not sure on your other questions, but as for this one:

2. Do you suppose the fish disease is related to the CO2 being so high? It could be a number of things, but I am worried about keeping the 2nd bottle hooked up if the CO2 gets so high.

If that fish disease is ich, then it can be definitely caused by the CO2. Don't get me wrong, it's not that CO2 causes ich, but that high a level of CO2 can cause stress in fish, and stress can cause/activate ich.

If, however, the "white spots" are not ich, then I am not sure. But again, many diseases/virii/etc can be in a tank, and just not active. It takes an opportune moment (or a moment of weakness) for the malign item to attack.

I hope everything gets through this.

 

[Steve Hampton]

You must have substrate, rock, or other decorations that have calcium carbonate. Calcium carbonate is largely insoluble...but carbonic acid increases is solubility, so yes, the more CO2 in your water the more carbonic acid and the faster calcium carbonate dissolves.

 

[rkilling1]

I am pretty sure (not positive) that a CO2 level of 107 ppm or even 96 ppm would kill any fish. not because of a lack of O2, but because the CO2 within the fishes body would not be able to be removed. ie CO2 poisoning.

 

[rkilling1]

You must have substrate, rock, or other decorations that have calcium carbonate. Calcium carbonate is largely insoluble...but carbonic acid increases is solubility, so yes, the more CO2 in your water the more carbonic acid and the faster calcium carbonate dissolves.

but it is also true that the more the KH or calcium carbonate goes up so does the Ph. that still doesn't account for why your numbers are so far off. with a KH change of 2 degrees, the Ph should of increased by .7 Ph units.

 

[Steve Hampton]

Yes, as KH increases so does pH. I've seen CO2 levels at 100ppm not cause problems if O2 levels are also very high. The problems occur much lower if O2 levels are low. Thats not to say I fully believe the CO2 levels are being properly determined, several factors can interfere with either test kit reading. If the fish are fine then its not a huge problem. A simple test can reveal a better guesstimate of the CO2 levels.

Take test kit readings of pH and KH from the tank. Then, remove a pint or so of tank water and place in a bowl to sit out overnight. This allows the CO2 to outgas and return to equilibrium. Tomorrow test the pH and KH of the bowl of water left out overnight and compare the two and report back the findings here. If there is test kit interference it should show up in these comparative results.

 

[CaptnIgnit]

Ah, very good idea on the that test! although, the fact that it ran down to 26 ppm of CO2 with one 2 liter hooked up matches what it used to be in the past. that would imply that there is nothing affecting the pH outside of the CO2.

I have hooked back up the 2nd 2 liter and will let the CO2 levels run back up. Tomorrow I'll do another test and see if it is still pushing the 100ppm level.

I am debating removing the rock I have in the tank. I did a vinegar test when I first got it and it didn't bubble, but I will probably remove it and try some of the muratic acid I have on it. I can't think of anything else I have in the tank that would affect KH. I have had my Eco-Complete in there for well over a month and I'm pretty sure any affects it had on KH have long since past with all the water changes. Only other thing I have is a stealth visi-therm heater, xp1 filter, CO2 reactor (made from 2 gravel vac's and some silicone with bio balls in it) and a piece of driftwood.

 

[7Enigma]

Yes, as KH increases so does pH. I've seen CO2 levels at 100ppm not cause problems if O2 levels are also very high. The problems occur much lower if O2 levels are low. Thats not to say I fully believe the CO2 levels are being properly determined, several factors can interfere with either test kit reading. If the fish are fine then its not a huge problem. A simple test can reveal a better guesstimate of the CO2 levels.

Take test kit readings of pH and KH from the tank. Then, remove a pint or so of tank water and place in a bowl to sit out overnight. This allows the CO2 to outgas and return to equilibrium. Tomorrow test the pH and KH of the bowl of water left out overnight and compare the two and report back the findings here. If there is test kit interference it should show up in these comparative results.

CO2 and O2 are independent of each other in regards to respiration. It does not matter if you have extremely high O2 levels if you also have high CO2 levels. This is a common and dangerous misconception that we as humans have to be careful about. Carbon monoxide is so dangerous because once it binds to your hemoglobin, it does not let go. This in effect is similar to high CO2 levels, as in both cases there is no room for O2 to bind. The CO2 can only passively diffuse into the water at levels ABOVE that of the water. So if you water has 100ppm CO2 dissolved, the fish's blood can only have greater than 100ppm CO2 present.

That being said while 100ppm is too high for my liking, its possible the fish are still able to respire effectively, but their kidneys are in overdrive right now and this could definately cause opportunistic diseases such as Ich.

 

[Zezmo]

The problems from DIY co2 are the lack of control. If your reactor is in-efficient, you are unlikely to get excess CO2. If your reactor becomes more efficent, then you run a danger of overloading the co2.

Last year, when I switched to a better diffusor on my DIY CO2, i also ended up with extreme CO2 levels. Plants love it of course, the fish not so much.

In this post I detail my experiences with excess CO2 and a DIY setup. Funny, I re-read my own post now and clearly see the series of mistakes I made while learning. FWIW, pressurized is well worth it, if nothing else because it can provide a more stable and controlled enironment for the animals.
http://www.aquariumadvice.com/viewtopic.php?p=521294&highlight=#521294


Here is a post right after I built the reactor, and had it on a powerhead. note, i mention 2x 2-liter bottles, that is a typo, I had 4x 2-liter bottles at that time.
http://www.aquariumadvice.com/viewtopic.php?p=472379&highlight=#472379