Hello all,

I am using the Milwaukee SMS122 and solenoid for my CO2 setup. Is anyone else using this setup turning their CO2 off at night? If so, I am curious how people are doing so -- what is the most sensible way?

I am thinking that cutting power to the SMS122 when lights go out might be the best way to accomplish this. Any thoughts?

Thanks,
Adam Aronson

I use a timer (be sure it has a 3 prong female receptacle), from HD, to shut mine down. However, supposedly, when you shut the lights out, the CO2 should cease to operate shortly thereafter. I use a singular timer to operate my lights and CO2 system. I have two multi plug receptacles plugged in to each other (series), then plugged into the timer, which is plugged into a power source. I plug my CO2 solenoid, pump for the reactor, and controller into one multi plug outlet. This is then plugged into my multi plug receptacle that carries the light and light fan. This is then plugged into the timer, which is in turn plugged into the wall. The reason for separating the lights and CO2 is to allow me, by flipping the on/off switch on the CO2 multiple outlet, to perform cleaning/maintenace to the CO2 units without turning off the lights and leaving me working in the dark. The multiple outlets can be had from WalMart for $3.00 apiece or so. The flexibility this system allows me far outways the cost in my opinion. An alternative, would be to plug everything into one multiple outlet (CO2 & lights), then into a timer, then into power source (outlet). This, obviously, would then shut lights and CO2 off together for a pre-determined time. I do not add any aerating device at night in my tank- never have had to, the fish do fine. :gw

Ditto.

Some use two timers and have the CO2 come on 1/2 hour before the lights and shut off the last 1 hour.

Regards,
Tom Barr

Thanks Jonathan and Tom for the suggestions.

I am fairly certain that killing power to the SMS122 will effectively prevent the solenoid from opening and any more CO2 from entering the tank so I may simply put it's AC adapter on a timer as well.

Adam

No!!! You don't need to kill the SMS122. The SMS122 and the solenoid are on two different plugs. Let the 122 monitor your pH 24x7, but have the other plug on the timer. That other plug is switched on and off by the 122 and that is what controls your solenoid.

If I'm not clear enough, let me know and I'll draw a picture

I think what they are getting at aronson is that you do not want to use the PH controlling part of the device. Just set a bubble rate which allows for say 30 to 40 ppm of Co2 during the peak of the day when photosynthesis is most active. Obviously the C02 would be less in the morning and more toward the end of the day, but it's fine.

You may think that this is a less accurate way of injecting your CO2, but consider this:

The PH controller is set to a certain PH. You enter this PH based on your KH reading and looking at the CO2 chart, right?

So say you measure KH 4' You would want a PH setting of 6.6 to achieve 30ppm CO2. You set it and forget it.

What happens if the KH changes??

Let's say the you do your weekly water change. You don't know it, but your water is now 2' KH. So now your tank is say around 3' KH (assuming 50% H20 change) You think you have 30ppm Co2 still because you see ph at 6.6, but in reality you only have 22ppm. You now may see some BBA and the plants are growing less- maybe not pearling as much and you are wondering what the problem is. The C02 is too low!!

With a calibrated constant bubble rate you will always have the same amount of C02 regardless of the KH. This allow you to enjoy your plants more and test KH less- and lets face it KH test kits aren't that accurate anyways. Will you see .5' KH change- probably not, yet it is enough to cause a C02 fluctuation. This is why I don't use a the controller part anymore, it's honestly not needed.

Jeff

when i measure kh in my 75 gal it comes up between 9 and 10 with ph of 6.5 to 6.6. if you look at the chart thats a lot of co2. is there something i'm doing wrong. using ap kh test kit and mill.digital ph tester. regards,cornhusker

Cornhusker, may want to read article on this relationship between CO2, KH, pH, at Chuck Gadd's website, http://www.csd.net/~cgadd/aqua/art_co2chart.htm. Phosphates may be the problem for what should be off scale high CO2 readings according to the chart, but if not, and the plants and fish are doing well, then there may be inaccuracies in the KH testing equipment. I set my controller @ 6.8 pH, GH @5-6, KH @ 6-7. I do have low carbonates from my test report, so I add sodium bicarbonate to the water to get my KH at that level (Hagen kit). I have gone higher on the KH with no ill effects, but that's under my conditions :gw

Call me a bit dense but I'm having a problem understanding the above concept.

When working only with a bubble rate you first need to find the rate that gives you your desired pH. Let's say you find that "sweet spot" at 1bps and let's say your KH is 6 and this gives you the 30-40mg/l of CO2 you want. Now your KH changes to 3. How will the 1bps still give you the same mg/l of CO2? You theoretically now need more CO2 injection to get the same mg/l of CO2?

Ok, now I've really confused myself!

Someone help me out here...

If you fix a particular CO2 bubble rate, then the KH and pH will vary, but, as you have set the CO2 rate, that will not vary. You will have whatever CO2 level (ppm) that particular rate will establish in your tank. Some people fixate on the bubble rate, some use the controller. I use the controller, my KH is initially low, so I can simply add sodium bicarbonate to my water to bring up the desired KH, and, according to the chart, at my selected pH on the controller, this will give me the desired CO2 level I need, or feel I need, for good plant growth. The plants determine my CO2/KH levels. If I had a high KH (17-18 degrees German) (otherwise known as rocks where I live) then the bubble rate would be the way to go, or RO water to lower the KH (I'm sure there are other methods as well but can't think of any), and maintain that CO2 level. Point to remember in all this- an erroneous pH reading will screw everything up quickly- this is the most sensitive of all your readings, if you use a test kit. :gw