CO2 Questions (new setup)

Sounds like you should be all set.
Now go here: http://www.csd.net/~cgadd/aqua/art_plant_aquacalc.htm
Download Chuck's calculator to your desktop where it will be handy for checking on nutrient dosages later and CO2 ppm now.
The CO2 content is based on the relationship of your kH to your pH.
BTW, you should make sure you have a kH of no less than 3.0°kH as a buffer to be safe for the fish. I've never used a ph/CO2 controller but I would suggest you set it at no lower than 7.0°pH and then test every 2 hours to see what kind of pH you are receiving. Once you determine how accurate the 'controller' is you will have a better idea of how to adjust. Do everything in small increments (by testing for pH) until you have no more than 20 ppm/CO2 at lights out. At that time your solenoid should turn the gas off. The bubbles/mist will not stop immediately when the gas is turned off. It typically takes a few minutes for what's in the line to be pulled through the reactor.
When the gas is turned off at night there is no reason to run O2 into the tank. There will be plenty of O2 in the water table for the fish. I ran my gas 24/7 for years without running O2 at night. Just no necessary, IMO.
Check your pH in the morning and it should have risen a couple of tenths over night while the gas was off. This is normal and not harmful to the fish. One of the reasons I frown on injecting O2 at night is that it will drive off the accumulated gas and the result will be more of a pH swing over night which is more stressful to the fish.
Then keep checking pH and adjusting CO2 flow during the next day until you find what your controller is giving you.
I would not leave it up to the controller to determine ppm, but rather keep checking pH and make sure you stay within safe CO2 limits based on the kH/pH relationship for a few weeks to be sure of the reliability of the unit. As you can see, I'm not very trusting of equipment until it shows me it's consistent and reliable. The fish come first, IMO.
I hope this is clear to you. It's really not as complicated as it seems initially.

Len

Don't inject any gas until you get your kH over 3.5°kH. Right now it is too low at 2°kH to buffer the water and protect the fish. Pick up some crushed coral at the LFS and put some in a nylon filter bag and into a filter. This will begin to buffer the water in a week or two.
I'm not sure that your numbers are correct. I would get your water tested at the LFS as well. If you take tap water let it sit on the counter and gas off for a couple of hours before testing. Tank water should be tested immediately after filling the vials. Have the LFS test for kH, gH, pH, phosphates and nitrates to double check against the numbers you've found at home. Tap water is important to know because it's your source water and every time you change water you re-fill with it.
Excel will cost you a fortune in a 125 gal. tank. If you intend to use a carbon source, pressurized would be the way to go, but there's no hurry and you really need to get that kH up before doing any injecting.

The questions are not dumb. They are the way we all learned and you will be advising people down the road, once you learn the ropes.

Len

djlen said:

Don't inject any gas until you get your kH over 3.5°kH. Right now it is too low at 2°kH to buffer the water and protect the fish. Pick up some crushed coral at the LFS and put some in a nylon filter bag and into a filter. This will begin to buffer the water in a week or two.
I'm not sure that your numbers are correct. I would get your water tested at the LFS as well. If you take tap water let it sit on the counter and gas off for a couple of hours before testing. Tank water should be tested immediately after filling the vials. Have the LFS test for kH, gH, pH, phosphates and nitrates to double check against the numbers you've found at home. Tap water is important to know because it's your source water and every time you change water you re-fill with it.
Excel will cost you a fortune in a 125 gal. tank. If you intend to use a carbon source, pressurized would be the way to go, but there's no hurry and you really need to get that kH up before doing any injecting.

The questions are not dumb. They are the way we all learned and you will be advising people down the road, once you learn the ropes.

Len

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I disagree whole heartedly.
I have run my pH from 5.8 to 6.2 with a KH of 2 and pressurized CO2, since March. No problems and crazy plant growth. That is a myth...pH crashes and the like. If you KH is around to as mine is as it comes out of my tap, it is fine. I use a pH controller and pressurized tank with an Aqua Medic reactor as well. Don't be afraid of low KH and low pH...it is your friend. The plants absolutely love it, and happy plants are happy fish!

thadius65 said:

Len,

Thanks for the info. The testing was at the LFS and then at home. The test that was used in both situation was aquarium pharm product, which is the 5ml bottle, one drop and then subsequent drops. very tedious and i got the same results as they did. PH is accurate, but I am not confident in the testing for KH. My guess is that it is very low, hence difficulty reading the test. I will get some coral.

THanks,!

Ted

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I would not do the coral thing!
That is what will cause issues. There is NO quatitative way to deliver Ca++ or Mg++ in this manner so it is out of control. I strongly disagree with this method. There os NO REASON why you have to mess with the water chemistry as long as your KH is 2 or so. Get a good KH/GH test kit and test it. 2 or more is FINE. Your plants will grow better! I grow hard to grow plants because they love this low KH and it is NOT harmful for your fish to be in a lower pH....MYTH If your plants are happy and you don't go over say about 30ppm CO2, your fish will be fine! Run an airstone at night or put your CO2 on a timer to turn off when lights go out. Do not start playing mad scientist with your water. Trust me on this. If you feel the need to play with your kh, use baking soda, NOT coral in your planted tank, but honestly you should not touch it. Be happy your kh is so low. Many others have high KH out of the tap and wish they had such a low KH to deal with. We discussed this and created real life experimentation with great results. Take a look at this thread to start, but realize...just because people did it that way in the past, doesn't maek it the way to go. http://www.plantedtank.net/forums/g...low-no-kh-low-ph-without.html?highlight=crash
Presently, I have a fast-growing plant farm...KH of 2, pH of 5.9-6.2, and even my 10 otos, considered sensitive fish, have been happy and busy since March when I put them in. My little guys have no complaints and my plants, well, I just donated another 40 bags worth of different species to my local Aquarium club, so take this advice if you so choose.

fish newby - Be very careful about the information you dispense when you know little about what you speak.
It is fact that without proper buffer, CO2 injection can cause the pH to crash. The commonly held theory on 'proper' in this case is 3.0 - 3.5°kH.
Just because you have had no issues with yours does not change the fact that not taking precautions can/will lead to heart breaking results over lost fish. I've seen it happen and I've spoken to many, many people over the years who started to inject without buffering up their water.
The kH of the water has little affect on the growth of plants. Mine have grown well at 3.5°kH for years and are now growing just as well or better at 6 - 9°kH (depending on the tank in question).
The fact that you suggest baking soda as an alternative to coral just points up how uninformed you are on this topic. Baking soda will buffer kH, but within 24 hours it's affect weakens and the kH once again reverts to form. Coral, while taking longer to act is a much more stable way of holding kH at a higher level more consistently.

Len

thadius65 said:

PH - 6.4 (due to use of peat in filter)
KH - 36

It reads that my CO2 is 24ppm and good. I am not adding any CO2 yet, but I have been adding Flourish Excel in the interim. This is a carbon additive, correct? Is this what is causing these numbers? GH is 53.7 for what that is worth.

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Normal water typically containes only a couple ppm of CO2, I dont beleive it will ever naturally rise above 5ppm but dont quote me on that one. It has also been said that Excel will not effect CO2 readings so something is definately off if you getting 24ppm. Also, make sure when you taking readings and punching numbers into calculators that you are using the right units. For example most all tests will be in either ppm or degrees. If you enter a KH value of 36 degrees when it should have been 36ppm that will make a huge difference just for example. Many things can effect your readings though, I am not the expert there, but things like phosphate buffers for example will skew the values and make the ph/kh chart invalid as-is. Basically the ph/kh chart will only work under very ideal controlled conditions. There are ways around these problems, but to complicated for me to remember off hand.

As for the low/no KH that is an interesting idea... I'll have to read more into this. But so far what I have read suggests that special attention be given to exactly what all inhabits the tank since not just everything can be placed under those conditions. If this all were true, I would still have to say its not for everyone so be carefull who suggest that this way is the only way and anything else is rediculous. As for the crushed coral I do beleive that is a proven method, not to say its required, but havent heard anything bad about it until now. I use baking soda myself, because its easy and I havent tried asking for crushed coral yet at any lfs's. But perhaps if there is truth to this low KH idea then I might consider gradually reducing my added baking soda and see what happens.