# First time CO2 set up questions



## aquascape1987 (7 Feb 2015)

Hi. As the thread title suggests,I'm just about to set up my first pressurised system and have a few questions. I'm using a 2.5 kg fire extinguisher,with a co2 art dual stage regulator with solenoid and needle valve,fed into an up aqua inline atomizer,which will be on the inlet of my fluval g6 filter. The aquarium is 190 litres and is going to be heavily planted,mainly with monte carol and sp Japan from the start. I've also got a ph controller,but I'm starting to have second thoughts about using this from what I read on here. My questions are:

What is the advised setting for the first stage valve on the regulator?

Injection rate: How many bps would you advise as  my base starting point? (Aquarium will contain fish)

How much dissolved co2 should I be aiming for as a starting point. E.g for maximum benefit to the plants, without harming the fish.I realise ill need to experiment and tweak,but really looking for a good starting point,bearing in mind I'll be keeping fish as well.

What colour would I be aiming for on my drop checker fluid,bearing in mind that my water comes from the tap soft and pH 7.5?

Could there be a useful application for the pH controller apart from using it for Co2 switching on and off in relation to pH

Thanks  in advance


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## Julian (7 Feb 2015)

Injection rate: What ever your fish can take before they start showing signs of stress.

What colour DC: aim for green DC at lights on. If you find that your pH continues to drop without leveling off after a few hours, you need more surface agitation to degass it, else your ph will drop and drop.

pH controller: I've had 3, I've come to the conclusion that they are only good for using as a safety feature. Do not use them to maintain a certain level else you will get BBA.


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## aquascape1987 (7 Feb 2015)

Thanks for that. So what would you set it at when using as a safety measure then?


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## aquascape1987 (7 Feb 2015)

Oh and what are your thoughts on a starting point bps injection rate for my size tank etc?


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## X3NiTH (7 Feb 2015)

Which controller is it?


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## aquascape1987 (7 Feb 2015)

Up aqua one. I got it all part of this package..... http://www.co2art.co.uk/collections...quarium-co2-system-for-plated-tank-up-to-500l


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## Julian (7 Feb 2015)

Find out what your fish are comfortable with, set the shut off level at that.


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## naughtymoose (7 Feb 2015)

I'm following this so that I can reduce double posting, as I will be asking the same questions soon for my 240L!


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## X3NiTH (7 Feb 2015)

There's two ways you can control with this UP controller, it has an HI and LO setting. 

The way it tells you to set it up for a freshwater tank is to use the HI setting which is the traditional method of closing the solenoid when the pH drops to a trigger point that you set, it will trigger the closing of the solenoid when the pH drops 0.05 points past your set point (as long as the solenoid power is plugged into the controller power block).

Alternatively you can use the LO setting which is intended for Saltwater use for dosing Kalkwasser, the way it operates here is that it switches on the the power when pH drops 0.05 pH past your set point and will turn off the power once it climbs 0.05pH past the set point. Instead of powering the solenoid you use either a power head or an Airpump to increase surface agitation within the tank, this increases the aperture of gas/air contact within the tank and allows the co2 to gas off.

The difference between the two methods is that the first method using the HI having solenoid control will mean all the lines will depressurise when gas switches off and there is a lag in it pressurising again when it comes back on, this means that the pH may climb beyond the 0.1pH variance (0.05 either side of set point), a variance above 0.1 is fluctuating co2 and invitation for BBA. The second method using the LO setting means the gas never switches off, the lines never depressurise so no lag and the variance remains within 0.1pH as long as the method used to increase gas transfer aperture is efficient enough. The variance of 0.1 has been said to be an acceptable fluctuation for plants not to suffer a shortfall. You can use the LO and adjust the level you off gas so that it hovers at your set point. 

I'm currently using the LO setting. 

You don't have to use it as a controller you can use it just to monitor the pH drop so you can correlate with a drop checker. You don't need to know what the exact pH off the tank as there are a few things that will influence the accuracy of the probe, the first is that if the TDS of the water is low the probe will have a hard time reading the pH, it will read but it will take a few minutes to stabilise and may be inaccurate by up to +/- 0.5 pH points. The other thing it is influenced by is impeller noise from a canister filter (stray voltage generated by a rotating magnetic field), you can test this by taking a reading with the pumps off, when you get a stable reading you turn the pumps on, if the value drifts it's being affected by stray voltage (voltage not current, current in a tank is a very very bad thing to have). I recently re calibrated my probe to tak into account this effect (set the pH to what the reading was before pumps on). What is important here is that it doesn't really matter what the pH exactly is you just need to see that the pH drops by an amount that correlates to a drop checker colour indication you desire (drop checker will lag by a couple of hours). My drop checker is always blue at lights on but my pH has dropped to a point where the DC will eventually go green/yellow some time later. This is my daily target pH but the tank pH may drift between water changes so I need to always check the drop checker to make sure I get it the colour I want at the start of each week, it's a very small drift but it's enough to cause a lot of confusion and a little bit of BBA.

Controller is just another tool, it's not foolproof but it can help you understand just how much co2 you actually need to inject to get the desired pH drop to keep your plants happy under their available lighting. You want to get the injection balanced enough for the controller never to be triggered, it's nice to know there is a back up safety net just in case something bad happens like an EOTD, I'd rather have grumpy plants and a bit of BBA than dead fish!

Since you already have it its worth trying it out just to see if you can get the 1 point pH drop and have it correlate with a green drop checker, it will at least tell you if you are going in the right direction.

Sorry that was a bit long winded, any questions feel free to ask!


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## greenmac75 (7 Feb 2015)

the point drop everybody talks about is that 0.1?


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## Andy Thurston (7 Feb 2015)

greenmac75 said:


> the point drop everybody talks about is that 0.1?


No 1.0 Or 1.2 in my tank


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## X3NiTH (7 Feb 2015)

I'm about 1.3 pH drop to get a drop checker indication of around 30ppm (negligible KH), 6.5 down to 5.2.


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## aquascape1987 (7 Feb 2015)

So the 1.0 pH drop is what we desire to achieve by injecting CO2. E.g a 1.0 pH drop from whatever the water was before injecting CO2?


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## aquascape1987 (7 Feb 2015)

And thanks for the detailed reply mate


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## naughtymoose (7 Feb 2015)

So, do you think that for a relative newbie, as I am, it is worth getting a pH controller? I ask because I may be able to get a Dennerle one for about 20 quid.


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## X3NiTH (7 Feb 2015)

aquascape1987 said:


> So the 1.0 pH drop is what we desire to achieve by injecting CO2. E.g a 1.0 pH drop from whatever the water was before injecting CO2?



It's a good number to aim for, you may need more or you may need less, it can depend on the KH (lower KH more than 1 point required, high KH maybe less than 1 point drop) and can depend on how well co2 has been gassed off before the next injection phase. I use strong aeration after lights out to degass the co2, when it reaches 6.5 (a couple of hours after lights off) I turn off the air pump and over the remainder of hours before the gas comes back on co2 from the atmosphere enters into the tank to drop the pH to 6.2. I have the UP controller set to gas of the excess via an air pump when the pH drops below 5.2 during the injection phase, I could go a lot lower with the fish being ok but my largest more mature shrimp show signs of stress below this figure and will congregate nearer the surface (small shrimp unaffected).


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## aquascape1987 (8 Feb 2015)

The only bit I don't fully get then,is.... how come everyone's aiming for the same green colour on the drop checker? If everyone is aiming for the approx 1 point pH drop,relative to whatever the ambient pH of their water was before  actively injecting CO2, and the drop checker being no more than a pH indicator solution. What I mean is,wouldn't some people's drop checker ideal colour be either more bluey or yellowish,depending upon what the pH of their water was out of the tap,some areas being more acidic,others more alkaline. Or am I misunderstanding this?


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## X3NiTH (8 Feb 2015)

naughtymoose said:


> So, do you think that for a relative newbie, as I am, it is worth getting a pH controller? I ask because I may be able to get a Dennerle one for about 20 quid.



That's a bargain price if the probe is still viable. They're great for doing pH profiles and gaining an understanding on how co2 behaves on injection and ejection (for me in low KH the pH will plummet alarmingly rapidly 3/4 of the way to a 1 point drop then get progressively harder to inject co2 over the next hour or so before lights on), and can be a good way to have safety net for the comfort of animals if too much co2 makes its way in (my concern was an EOTD using a single stage regulator).

I wouldn't recommend having it control the solenoid for the comfort of plants unless you set it well below your preferred equilibrium point to prevent any unexpected extra injection of co2 to the detriment of animals in the tank. For me having the UP set to off gas is the softer option to closing the solenoid. I have a Weipro controller in my tank also at the moment and it has control of the solenoid but it's set to a point to switch off the solenoid at a pH that I would likely see all my fish gasping at the surface and shrimp climbing out the tank, the UP switching on the airpump ensures the solenoid doesn't go off (unless the air pump fails, to be sure to be sure).


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## aquascape1987 (8 Feb 2015)

How do you rate the accuracy of the UP
X3NiTH?


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## X3NiTH (8 Feb 2015)

The drop checker is an independent system to the tank water, it should contain a known reference solution (typically 4dKH) and an indicator fluid (Bromethyl Blue). The drop checkers pH and colour change is only influenced by the amount of co2 that the tank water contains that comes out of solution and enters the bell. The drop checker will behave the same way regardless of what tank its in.

Tank pH can fluctuate due to biological influences so what it is one day may not be the same the next. For me very small variance in the 0.00s range that over the space of a week (between water changes based on EI principle) may rise by 0.02pH (+/-0.01pH accuracy of controller probe), if I feed the fish a little more then it may go the other way.



aquascape1987 said:


> How do you rate the accuracy of the UP



The UP has a finer variance than most controllers at 0.05pH either side of the set point (0.1pH total variance +/-0.01 accuracy), my Weipro variance is 0.9pH either side of the set point (0.18 +/-0.01 accuracy).

Running two together in one tank I have discovered that they won't always give me the same reading even though both are calibrated correctly and adjusted to read the same values, the UP influences the Weipro a little and will skew its readings as the pH drops so that the Weipro is out by about 0.05pH points at the full drop. The UP has two point calibration pots on the controller for pH7 and pH4 whereas the Weipro only has one for pH7 so for calibration accuracy the UP has it.

Both still read their calibration fluids accurately so my probes are still in good condition, they just don't like being in the same tank together with an actively running filter generating stray voltage (if the pump flow fluctuates then the stray voltage will fluctuate, if the stray voltage fluctuates then the probe readings fluctuate). Also depending on how low the TDS is from tank to tank I can get differing results on multiple testing. It's been no walk in the park and I've been left scratching my head on many occasions but the drop checker has ensured that I'm always going in the right direction

Between the two I prefer the UP for being able to use it to degass co2 than cut it off completely. 

As for accuracy that's a tough one because things happening in the tank can influence it greatly like TDS and impeller noise that leave me wondering, same goes for the Weipro, but they are close enough for them to be useful in conjunction with a drop checker.


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## aquascape1987 (8 Feb 2015)

Of course! The drop checker measures the pH of the atmosphere rising from the water,rather than the water it's self. Thanks man. That was a real Eureka moment ha


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## THZ (15 Mar 2015)

Hello
I've got the same controller, just labelled as PH-201 and wonder about the low hysteresis of 0.03 only. I set mine to 6.82. When reaching 6.85, CO2 starts - until going down to 6.79. For me, this is way to low, therefore the controller switches about every half hour! Do you experience the same issue?


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## aquascape1987 (16 Mar 2015)

Hi THZ, I'm yet to test it to be honest, but after advice that I got on ukaps,I was thinking of removing the power actuator and just using it as a PH meter. Eg providing a power supply to the controller and sensor bit and removing the bulky plug socket box that the solenoid plugs into. So your saying that your experience with it isn't good as it is constantly switching the co2 on and off...? 0.06 ph variance doesn't seem much in terms of pH , but  I would hazard that this is creating wild drifts in the amount of co2 dissolved in the water over the photo period,considering the colossal difference 1ph signifies. It's 10 x difference in the amount of dissolved Co2 if I'm not wrong?


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## THZ (17 Mar 2015)

Hi aquascape1987: yes, my experience isn't good as the hysteresis is by *0.03 *only! 
I set a PH value of 6.82. So, when reaching 6.85, the controller switches the co2 on. When going down to 6.79, the controller switches co2 off. I tried to reduce the amount of bubbles, so that it takes longer to reduce from 6.85 to 6.79, but when reducing the bubbles too much, the pH won't go down. It needs a certain amount of bubbles for working correctly. Due to this small hysteresis, the pH is being reduced from 6.85 to 6.79 within half an hour only. So you can imagine how often the controller switches the solenoid on and off.


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