Couple of Milwaukee SMS122 Questions

[FreakIndeed]

Just got an SMS122 and there were a couple of things I didn't find clear in the manual that I thought someone may be able to help me with. First, I have a little card that says to only calibrate the unit to pH7.0 for aquarium use. Does this mean that I don't do the pH4.0 "Slope" calibration?

Second, the manual says to re-calibrate the unit every month. Do most folks find this necessary? Can I save the pH7.0 solution in an airtight container and reuse it? Or do I need to stock up on some of these little packets?

Also, the manual says to soak the tip if it is dry in M10000B rinse solution to reactivate it. However this was not provided, is there something else to use?

Lastly, when using these units do I set the regulator pressure as directed in the manual and then leave the needle valve completely open?

Thanks!!!

[Plecosterone]

I have 2 of those and never calibrated for pH4 like it says and they work fine. I haven't re-calibrated mine since, one was installed over 10 months ago and the other about 4 months ago. I don't feel the need to re-calibrate just because they say to. Just check your pH once in a while and make sure it matches pretty darn close to what the controller says. I think what they mean by the tip drying out is when it has been stored for a while. I never reactivated mine and they work. Set the regulator as directed but I only leave the needle valve open enough to make sure it is all getting diffused. This will vary depending on your diffusion method. If the unit is staying on for a long time, turn the needle valve up. This will take some playing with over the first week or 2 and then you can leave it pretty much alone.

[confusion]

I bought one of those setups, and I believe it had me do the whole calibration deal with the ph4, ph7 and ph10 (IIRC). Now having said that, I *never* get the tank to have a desirable level of CO2 - I just cannot dissolve it fast enough, so for me, anyhow, the ph meter is pointless, unless I get some kind of more efficient diffuser.

[Plecosterone]

I bought one of those setups, and I believe it had me do the whole calibration deal with the ph4, ph7 and ph10 (IIRC). Now having said that, I *never* get the tank to have a desirable level of CO2 - I just cannot dissolve it fast enough, so for me, anyhow, the ph meter is pointless, unless I get some kind of more efficient diffuser.
How big is the tank and how are you diffusing the CO2? The bigger the tank is, the better the diffuser has to be. It will take time even with a good diffuser. Nothing is instant. I have a 75 & 90 gallon and the CO2 usually stays on for no more than 1-1/2 hour at a time.

[confusion]

I have a 125G tank. I start the CO2 diffusion about 1 hour before my lights come on in the morning. When the lights go off at night, the co2 goes off and an air pump turns on. There is no surface disruption, so I have had fish gasping in the morning, which prompted the air pump. If I continued the diffusion during the night, I can move the ph, but I can't move it more than about .5 while the lights are on. The plants are doing a small amount of pearling.

[loaches r cool]

I'll re ask what pleco asked...
how are you diffusing the CO2?
As in what kind of diffuser... if you cant get your co2 up then you have a problem... and if it cant be fixed youll have to adjust your light & ferts (unless you already have of course). When you say you cant move your pH more than .5 what is that from? .5 isnt a whole lot if your talking about a completely de-gassed aquarium water sample but if your just comparing it to the night time pH that might be plenty. Do you use a drop checker or any other way of testing the co2?

And for the OP, it might not be asbolutely necessary but if possible I would always do at least a two point calibration. My controller requires it. If your pH sits close to 7 under normal usage and the slope isnt too far off than no big deal. But the further you go from 7 if your slope is off it will increase. Like for every .5 pH unit your slope is off by .1 then lets say your pH is at 5.5 it could be off by .3. So it really could be up to 60ppm (if the pH were 5.2) of down to 15ppm (if the pH were 5.8) which is a lot of difference! That example might be extreme, but you get the idea.

As far as calibrating the probe if you arent going to do it every so often then dont use a controller. The calibration packs are like less than a buck and you dont have to do it very often. You can verify calibration by testing the pH with another kit, but thats not all that accurate, at least for those of us who dont seem to be able to decipher shades of green or whatever all that accurately.