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Discussion Starter #1
Hi,
I was just wondering if you are trying to get to a certain pH with your controller, then it shouldn't matter how many bubbles per second you use (assuming it isn't ridiculous) - is this a correct assumption since the controller will shut off at a given pH, regardless of bubble count. So question is, does bubble count (within reason) have much bearing on a tank or is it just whatever works to get the pH to the desired level from the non-CO2 normal 'high' pH? In other words, does it really matter, if you have a tank at 7pH and you want to fluctuate between 6 and 7 pH, does it really matter how fast (via bubble count) you get to 6, since the controller will keep it at a minimum anyways?

Thanks!
 

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Hi,
I was just wondering if you are trying to get to a certain pH with your controller, then it shouldn't matter how many bubbles per second you use (assuming it isn't ridiculous) - is this a correct assumption since the controller will shut off at a given pH, regardless of bubble count. So question is, does bubble count (within reason) have much bearing on a tank or is it just whatever works to get the pH to the desired level from the non-CO2 normal 'high' pH? In other words, does it really matter, if you have a tank at 7pH and you want to fluctuate between 6 and 7 pH, does it really matter how fast (via bubble count) you get to 6, since the controller will keep it at a minimum anyways?

Thanks!
If using a reactor you can overwhelm the reactor (different point depending on the size and construction of a reactor) and thus make it pretty noisy. If using a diffuser you won't have this issue, but at some point your tank will have a LOT of bubbles floating around in it. Same for infline diffuser.
 

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Discussion Starter #3
If using a reactor you can overwhelm the reactor (different point depending on the size and construction of a reactor) and thus make it pretty noisy. If using a diffuser you won't have this issue, but at some point your tank will have a LOT of bubbles floating around in it. Same for infline diffuser.
Thanks minorhero for making the distinction. I don't mind the 'Sprite' effect, just don't want to gas any fish with a short burst of excessive CO2, is all. Much appreciated.
 

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i've given this some thought with my own tanks, and i think there's still a benefit to having a reasonable co2 rate with a ph controller because the controller can fail. if you really blast the co2 (assuming your reactor can handle/process it) you'll get up to your target quickly and will have a lot of on/off controller cycles throughout the day. there's nothing wrong with that but if the controller fails in some way, you can blow past a safe point very quickly.
 

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So my situation could be very different from yours, since you didn't mention an end goal. But this is my 2 cents, if you are trying something else, ignore all this stuff. lol. But I am just using the CO2 to make sure my plants are getting at least what they need and hopefully a little more to keep growing constantly in my 75 gallon. I will probably one day sell a few clippings and things but I am not trying to make them grow their 100% fastest.

I would just try to find a good balance. CO2 levels can take awhile, even with a dialed in reactor, to give you an accurate/this instant kind of reading. If you don't have flimsy fish I suppose I wouldn't mind pounding in CO2. But in general the plants will learn to use what they have so unless you are growing for resale, I would just change it once or twice a week until you get the desired amount you want. I have dialed mine in to a good amount of bubbles, got a large defuser so I can have more of the smaller bubbles and have a spray bar that sort of ping pongs the bubbles back down through the whole water column and basically end up with no surface bubbles at all throughout the day. This took a good month of the tiniest tweaks and watching the plants and fish so none flip out all of the sudden. I also got GH and KH tests just to be sure but I am not at all close enough to the 1.0 PH drop for me to keep measuring those. I do on occasion when I want a full picture of my water parameters.
 

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I'm relatively new to CO2. The bubble counting drove me crazy. I went with an all CO2 Art setup and the needle value/bubble counter is just not that reliable and would be fast one day and blip ... blip ... blip the next. It might have been a temporary product issue as they sent me a replacement out of the blue many months later (I have not tried it yet). But I gave up checking and counting the bubbles and went with a $120 Milwaukee pH controller. Best decision ever!!! I still have the needle valve/bubble counter inline but I just put it on rather fast and let the controller deal with it.

My water is ~ 7.2pH nominal and I set the controller to turn off CO2 @ 6.3pH. Many people go lower but I'm not greedy, get plenty of growth and don't need to risk my fish. The controller really turns it into set and forget, you won't bother with the needle much anymore.

The failure modes of a controller are that (1) if your nominal pH changes, then you need to adjust the controller set point otherwise you'll get too little or too much CO2 (but that's the beauty of the pH controller, it tells you the pH 24/7!) and (2) you need to keep the probe calibrated, although I notice if they are in water 100% of the time, they don't seem to get out of calibration. When I do a water change, I push the probe further into the aquarium to make sure it's in water all the time.

The controller doesn't cost that much, I highly recommend it if you are serious about CO2.
 

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Just a note for anyone using aquasoil-type subs that lower KH, you dont want your co2 tied to a set ph level in that situation. Because as the KH drifts up and down (ie between water changes) keeping the same PH will have varying degrees of CO2. You need a rock solid KH to use a controller for CO2
 

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On the same note as Burr, you also can't use a pH controller if you have hardscape that will leech KH, like Sieryu Stone.
 

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On the same note as Burr, you also can't use a pH controller if you have hardscape that will leech KH, like Sieryu Stone.
I have loads of Sieryu Stone and I use a pH controller successfully. I keep up with water changes and after a while the Sieryu seems to not have an effect, which was mild at first to being with.

The warnings are meaningful but I would use the controller even if I had aquasoil. You just have to keep an eye on your nominal pH (usually a few hours after CO2 is off) and adjust accordingly.

I will say too I don't even use a drop checker anymore. I recommend that when starting out however!
 

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I have loads of Sieryu Stone and I use a pH controller successfully. I keep up with water changes and after a while the Sieryu seems to not have an effect, which was mild at first to being with.

The warnings are meaningful but I would use the controller even if I had aquasoil. You just have to keep an eye on your nominal pH (usually a few hours after CO2 is off) and adjust accordingly.

I will say too I don't even use a drop checker anymore. I recommend that when starting out however!
My tank leeches 3-4 degrees of hardness during the week between water changes, and that would equate to a SIGNIFICANT difference in CO2 concentrations. I suppose each tank is different, but I would never be able to get away with a CO2 controller. I would forget to change the target pH one day and gas my fish before I got home from work.
 

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My tank leeches 3-4 degrees of hardness during the week between water changes, and that would equate to a SIGNIFICANT difference in CO2 concentrations. I suppose each tank is different, but I would never be able to get away with a CO2 controller. I would forget to change the target pH one day and gas my fish before I got home from work.
Mine did that too. I would go from gh 11 --> 14 and kh 5/6 --> kh 7/8 in a week. Due to this and due to shrimp that I don't want to force into a molt with a big water change, I do daily 9-10% water changes (50g tank = ~ one 5g bucket a day). That seems to keep it stabilized. My values never move now. Also that leach effect seems to have less effect on nominal pH than I thought it would.

Any way, tank full of Seiryu, no drop checker, pH controller only, caution to the wind - no fish deaths, no algae that pops up due to CO2 fluctuations ... so far (knocking on wood) ... Tank is 7 months old.
 

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I have loads of Sieryu Stone and I use a pH controller successfully. I keep up with water changes and after a while the Sieryu seems to not have an effect, which was mild at first to being with.

The warnings are meaningful but I would use the controller even if I had aquasoil. You just have to keep an eye on your nominal pH (usually a few hours after CO2 is off) and adjust accordingly.

I will say too I don't even use a drop checker anymore. I recommend that when starting out however!
Bolded part: This can be hard to understand at first, but it doesnt work like that. Say your target PH level with co2 on is 6, and you have a controller set to kick off when the drop reaches 6, back on when it rises. That's all well and good if the KH never changes.

The reason you need a stable KH to do it this way is because the CO2 level at a specific PH changes dramatically if the KH changes. See the old familiar PH/KH chart, notice what a difference even a .5 change in KH makes to the co2 level at the same PH

505c3784999e4.jpg


If the KH is moving, the PH needs to be free to move too, otherwise there'll be massive swings in CO2 levels.
 

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Bolded part: This can be hard to understand at first, but it doesnt work like that. Say your target PH level with co2 on is 6, and you have a controller set to kick off when the drop reaches 6, back on when it rises. That's all well and good if the KH never changes.

The reason you need a stable KH to do it this way is because the CO2 level at a specific PH changes dramatically if the KH changes. See the old familiar PH/KH chart, notice what a difference even a .5 change in KH makes to the co2 level at the same PH

View attachment 1028067

If the KH is moving, the PH needs to be free to move too, otherwise there'll be massive swings in CO2 levels.
Agreed, that's a big reason (and my shrimp) I do daily water changes vs let parameters fluctuate and then reset once per week or every other. I have one set of numbers now that the tank is always at. It never changes.

I also do not target absolute maximum CO2 enrichment. I go for 7.2 --> 6.3 which leaves buffer (which I used to have it at 7.2 --> 6.5 and gradually moved it down). So that's a strategy if you want looser tolerances and/or have Seiryu. I'm not trying to win contests and also prefer trimming every other week (or I wish once a month), so I don't want maximum growth. I would not recommend this setup with its intentional loose tolerances for someone trying to maximize everything.

That chart is a rough guideline, I've seen people on here post that they supposedly accidentally had CO2 in the hundreds (based on the chart) without losing any fish. I would not risk going outside the bounds the chart shows and used it to get my tank configured, but I do wonder about its accuracy.
 

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Right, the chart is not accurate as far as calculating real time ppm. It is useful to this discussion however, because it illustrates what happens to CO2 at the same PH level if the KH changes, and the degree to which it occurs. That part is not in dispute ;)

It sounds like you have a system going to compensate pretty well and thats great. But its something folks should understand about using a controller with soil-type subs
 
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