pH controller, should I use it???

gmoney

Junior Poster
Nov 14, 2005
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I have previously run pressurized CO2 into my tank through a internal CO2 reactor (inverted gravel vac with powerhead attached). The system is controlled with a pH controller set at pH of 6.7. I am very interested in adding a bubble mist and have ordered the fine mist sweetwater airstones from aquaticeco. The point I am confused about is:
1. Whether I should continue to use the reactor and just add an airstone near a filter outlet?
2. Keep the pH monitor hooked up to control the system? Or just let it bubble in during the day? (the last Barrreport talked about ability of fish to tolerate wide pH swings, but it wasn't clear to me whether I should let this happen if I don't have to)
3. Remove the reactor and add a couple of airstones with the pH controller in place?

The tank is 75g, 220w CF, heavily planted, heavy fish load, fluorite/profile mix, with pressurized CO2 with pH controller (off at night)

Thanks,
Gary
(confused in north cackalackey) :confused:
 

gmoney

Junior Poster
Nov 14, 2005
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Re: pH controller, should I use it???

No replies, so I'll tell you what I decided.
I ordered the fine mist stones from aquatico.
I hooked up one inside of the reactor and took the sponge out of the bottom. My thought is that this would bounce larger bubbles around and maybe spit off some of the smaller mist-type bubbles.
Second, I split the line with brass t-connector and ran the second line to a fine-mist airstone underneath a powerhead on the opposite side of the tank. The pH controller was left installed, now set at 6.5-6.6.

All of these modifications were done after weekly maintenence and a moderate pruning. Now the race is on between the sides of the tank.
 

Spar

Guru Class Expert
Jun 5, 2005
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Dallas, TX
Re: pH controller, should I use it???

I generally recommend to ditch controllers. primary reason being that you no longer have controls over electronic error. if something happened to were the pH reading was not correct, the controller would automatically compensate the co2 to reach the pH that you specified. What happens when the off pH results in a co2 of 100ppm? fish die.

It is a lot safer to just know what bubble rate to expect out of your co2 system, and then just leave it and adjust as necessary later. Use the pH monitor from the controller as your basis for whether to increase/decrease your bubble count.

the difference here is that you can use common sense when manually adjusting something, where as the controller will not do this. If your pH/KH combo tells you to increase co2, yet you are now at 8 bubbles per second, you can assume that something is not right. The controller would just say, "ok, lets go to 8bps".

And fish are fine with pH changes due to co2, so don't let that sway any of your decisions.
 

gmoney

Junior Poster
Nov 14, 2005
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Re: pH controller, should I use it???

Thanks Spar. It will be hard (since I paid some bucks for it), but I guess I can disconnect my pH controller. It will still be useful for a pH monitor.
 

Jeff Bodin

Junior Poster
Feb 19, 2005
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Re: pH controller, should I use it???

Spar said:
I generally recommend to ditch controllers. primary reason being that you no longer have controls over electronic error. if something happened to were the pH reading was not correct, the controller would automatically compensate the co2 to reach the pH that you specified. What happens when the off pH results in a co2 of 100ppm? fish die.

It is a lot safer to just know what bubble rate to expect out of your co2 system, and then just leave it and adjust as necessary later. Use the pH monitor from the controller as your basis for whether to increase/decrease your bubble count.

the difference here is that you can use common sense when manually adjusting something, where as the controller will not do this. If your pH/KH combo tells you to increase co2, yet you are now at 8 bubbles per second, you can assume that something is not right. The controller would just say, "ok, lets go to 8bps".

And fish are fine with pH changes due to co2, so don't let that sway any of your decisions.

I disagree - I've had much wider pH and C02 swings without a controller, and now that I have one, I love it.

Without a controller you can have something happen and lots of CO2 inadvertantly get dumped in the tank (End of tank dump, temp swing affecting bps, mechanical error, etc...).

If a dump starts to happen (or needle valve go whacky because of a temp swing) with a controller, the solonoid turns off when the dump is happening at your given pH and it DOESN'T go lower...

And I do have very fast BPS (not sure if its 8, but wouldn't be suprised...) because of my tank needs... I could never manage it consistantly without the controller - always was winding up with very little C02 or way too much CO2.

I have a much larger trust in electronics than I do mechanicals. Electonic component MTBFs (calculated Mean Time Between Failures) generaly surpasses Mechanical MTBFs by factors from hundreds, to sometimes thousands...

As always (and shown in this thread), Milage (and opinions) may vary.

- Jeff
 

Spar

Guru Class Expert
Jun 5, 2005
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Dallas, TX
Re: pH controller, should I use it???

Jeff Bodin said:
I disagree - I've had much wider pH and C02 swings without a controller, and now that I have one, I love it.

Without a controller you can have something happen and lots of CO2 inadvertantly get dumped in the tank (End of tank dump, temp swing affecting bps, mechanical error, etc...).

If a dump starts to happen (or needle valve go whacky because of a temp swing) with a controller, the solonoid turns off when the dump is happening at your given pH and it DOESN'T go lower...

And I do have very fast BPS (not sure if its 8, but wouldn't be suprised...) because of my tank needs... I could never manage it consistantly without the controller - always was winding up with very little C02 or way too much CO2.

I have a much larger trust in electronics than I do mechanicals. Electonic component MTBFs (calculated Mean Time Between Failures) generaly surpasses Mechanical MTBFs by factors from hundreds, to sometimes thousands...

As always (and shown in this thread), Milage (and opinions) may vary.

- Jeff
Ya, this will just have to be where opinions vary :)

My main reason being that I have used a pH calibration fluid before that ended up being .5pH off from what it said it was (supposed to be 7.0, but turned out to be 6.5), but since you calibrate the unit manually (i.e. Force it) to read 7.0, you are from there on measuring pH at .5 off. Thus, your co2 rate will be significantly miscalculated. If the calibration fluid was off from the start, the user really wouldn't benefit from either method (controller or no controller), as no previous bubble rate would be on record to go off of.

But, a continuing user would wonder why the sudden sigificant increase in bubble count was required, while a controller would just start dumping in co2 to bring the pH where the controller wants it to be (i.e. .5 off in this situation).

I have had the end-of-tank dump before, so I 100% agree with you on that being a useful safety control of having a controller, but all the other factors are what keep me from having one.
 

Jeff Bodin

Junior Poster
Feb 19, 2005
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Re: pH controller, should I use it???

And I hate trying to interpret bromothymol blue. 0.5 isn't deadly unless you're not on top of your kH.

Lost $300 tank of rams and discus due to End of tank. Wasn't pretty.

- Jeff
 

jonathan11

Lifetime Charter Member
Lifetime Member
Jan 24, 2005
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Re: pH controller, should I use it???

Gary,
How are the air stones working out? Do you find any less use of CO2 with better plant growth? Do the stones require a pump/powerhead to better distribute the flow? A lot of questions, but I'm sure a lot of us would like to know the effects and results. :D :D :D :gw

Walter
 

gmoney

Junior Poster
Nov 14, 2005
7
0
1
Re: pH controller, should I use it???

Thanks for all of the input. Things seem to be going pretty well. The mist from the sweetwater stone has very fine bubbles. The stone is set below the output of a powerhead (directed slightly downward).

Since setting this system up I have noted several interesting things. The bubbles that initially came out of the sweetwater stone were fairly coarse. Over a day, they became finer...more misty. As the bubbles became finer, they were dispersed nicely by the flow of the powerhead. Here is a pic of the bubbles (not the greatest pic, but you can appreciate the small bubbles and how they are moved laterally).


Here is the other thing that I noticed. When I first hooked the airstone up, I spliced a brass t-piece into the existing line (that ran into the gravel-tube/powerhead reactor). Initially the CO2 just poured into the reactor. I figured this was due to a pressure differential because the airstone needed a higher pressure to drive it than the open end of the tubing in the reactor. So, I put an another sweetwater airstone on the end of the reator tubing (inside of the reactor). Now here is where it gets a little wierd. Both stones will not run simultaneously. One or the other will run, and it seems random which it will be. I thought that maybe Laplace's [sp?] law might be coming into effect due to different tubing lengths, but this didn't seem to explain the randomness of which stone would output. Here is a pic of the gravel vac-reactor taken just moments after the above picture. The thing to note (maybe hard from the small picture) is that there are no bubbles in it.



Can I get to the bottom line....okay here goes:

The plants seem to be doing a little better. I am noticing better pearling on the right side of the tank (side with open airstone). My Eichhornia diversifolia are showing much improved growth. I have been battling some hair algae recently on the Eichhornia.

Anyway...so far so good. I will keep posting with results. Hope this wasn't too boring.

Here is a recent full tank shot: