# What should the PH be set at on a PH monitor?



## ethanhunter (Jul 31, 2009)

Hi,

I was looking to get a Ph controller for my 55g planted tank
http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4416+4493&pcatid=4493

What should the PH be set at? I do have tetra and rainbowfish.

If any of you used a ph controller like this one, what experience have you had with it?
Does it make eaiser to keep the ph and co2 stable in tank? Is it worth getting? I was looking to get a drop checker to.

Any advice or help is appreciated

thanks


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## Bert H (Mar 2, 2004)

I've never used a pH controller. Typically you would aim for a pH unit 1.0 below the degassed tap water (source) you use for your tank. 

I'm sure there are lots out there who will disagree with me on this one, but if it were me, I'd save my $$. With $200, you can upgrade a variety of items. A solenoid for the tank and a drop checker should work well for you (and be cheaper), though it may require a bit more 'hands-on' to get it set right. 

My 2 cents.


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## Andy Ritter (Nov 26, 2008)

Ethanhunter,

I have had that exact same pH controller for years and love it. I have never had any problems with it and highly recommend it. Every so often (3-4 months) I check the calibration using the calibration fluids sold for it, but it is rarely off by much. When it gets to the point that it doesn't keep it's calibration as good anymore, I replace the electrode (which according to the manufacturer is supposed to be replaced every 18 months, but in my case they usually last at least a couple of years).

I used to try to set my CO2 levels by counting bubbles and tweaking a needle valve, but became so frustrated with the pH swings that I finally gave up. With a pH controller (technically it's a CO2 controller), all you have to do is set up a decent flow rate with the bubble counter, and then sit back and let the controller do the rest. It automatically turns on the CO2 when the pH gets to the high set-point, and then turns off when it gets to the low one. This is especially beneficial when the lights turn off and the plants start using oxygen and giving off CO2. The controller automatically turns off the CO2 and then turns it back on again when needed (which is usually sometime after the lights come back on and the plants start using CO2 again). I don't run an air stone at night because I don't have to.

Now, answering your question involves asking some other questions. It depends on what your KH is and what the target concentration of CO2 is. In other words, it varies from tank to tank. In my case, I use a low set point of 6.8 and a high point of 6.9. I use the Reactor 1000 (also sold on Doctors Foster and Smith) hanging on the back of the tank (a 75 gallon), and it seems to me to be very efficient. When the CO2 comes on, the pH almost immediately starts going slowly back down. When the CO2 goes off, the pH will sometimes drop down to a little over 6.7 before it starts slowly creeping back up. This cycle happens all throughout the day and the fish don't seem to be stressed by it at all. I also use a drop checker with 4 KH water in it to double check the CO2 concentration. It stays light green pretty much constantly, and I have never noticed the fish "gasping", and I have pearling on the plants. I just checked the KH of the tank water the other week and noticed that it is up to 9 (my well water is around 6-7). I started using PPS pro earlier this year, and I think that I may have to tweak the MgSO4 amounts that I'm adding to keep it from going up so much. My point is that since the KH affects the pH, you have to set the controller for your tank based on how much CO2 you want. If I was to accidentally let the KH of the tank water get up too high, the controller is going to keep adding CO2 in order to maintain the set pH, which would allow the CO2 to get way too high. That's why I like the drop checker so much; I can just quickly glance at it to see if I need to worry about the CO2. You'll have to set the pH controller to settings that allow you to keep the drop checker at the amount of CO2 that you want. Hopefully you won't have to adjust the KH of the tank water in order to keep the pH where you would like it.

I hope this has helped.

Andy


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## bosmahe1 (May 14, 2005)

I'm pretty sure MgSO4 effects GH not KH. KH is effected by sodium carbonate and sodium bicarbonate.


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## bosmahe1 (May 14, 2005)

Otherwise, great explanation.


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## Andy Ritter (Nov 26, 2008)

bosmahe1, you're right, I feel stupid. :doh: 

I am so bad about researching how everything works, figuring out what to look for and how to do it, and then forgeting the whys. I just remember seeing a thread in the PPS forum where there was some discussion as to whether MgSO4 was really necessary if you have harder water, but I didn't actually go back and refresh my memory on GH and KH to see the relationship. I had already mixed up a fresh batch of PPS pro and figured I would look into it some more when I need to make more.

Sorry for the misinformation. :sorry:

Andy


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## Veloth (Jun 25, 2008)

I agree with Bert H. I would use the money for something else. I don't even use a drop checker any more, I watch my plants and my fish and so far everything is good. Of course when I get home tonight all my fish will be dead, just because I've said something about things being good.:sad:


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## cbwmn (Dec 18, 2007)

I have a Milwaukee setup and I also don't use DC's anymore.
My Milwaukee pH controller is very accurate. I check the calibration about every month or so and so far have not had to re-calibrate it.
As for drop checkers, they are not accurate. If you are content with knowing ABOUT what CO2 concentration is,
a DC is fine. But with a controller, you can easily adjust
the pH and watch your plants for pearling and the livestock for distress. Also, DC's just add more equipment inside the tank.
My solenoid and pH controller are on a timer, so everything is off at night when CO2 is not needed.
Charles


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## ethanhunter (Jul 31, 2009)

Thanks guys! I will look more into it


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