Another stinking reactor question

AZFish1 · May 27, 2005

Ok ... so I want to try this reactor http://www.gwapa.org/articles/inline_co2_reactor/
The article says it is used on the input side of the filter and that sounds good to me since any bubbles that get through will get chewed up by the impeller in the canister. My concern is that it might be less efficient than the in tank venturi design I am using now. Anyone have any experience with this type design? Can you get a 30 ppm co2 level with it? My tank is 50 gallons and probably holds only 40 gallons of water. I emailed the author and he said he has no problems with it clogging up or with airlocking the canister. Also said the he takes it off every six months or so and runs a garden hose through just to be on the safe side. I will be adding a clean out to it.
Once again, thanks to all in advance

hadog · May 27, 2005

Re: Another stinking reactor question

This looks interesting.....does he have a how to file? I hate trying to build things from pictures.

Could the Magum 350 do the same job I wonder?

AZFish1 · May 27, 2005

Re: Another stinking reactor question

Here it is with a parts list.... This is from the designers site. The rest of the site is worth a look too

http://www.aquaticscape.com/articles/co2reactor.htm

Greg Watson · May 27, 2005

Re: Another stinking reactor question

AZFish1 said:

Here it is with a parts list.... This is from the designers site. The rest of the site is worth a look too

http://www.aquaticscape.com/articles/co2reactor.htm
Click to expand...

In my 180 gallon tank, I switched from a "commercial" reactor almost identical to this DIY one above -->> to a slightly modified in tank Venturi Reactor built by our own Cornhusker modeled after Tom's Venturi design ...

I think I have been using it for almost a month now ...

1. I was sure that one internal venturi would not be enough, this is handling my 180 gallon tank just fine ...

2. I used to go through about one CO2 tank every three weeks, I'm on week five now ... so I know I'm using a LOT less CO2 ...

My concern is that it might be less efficient than the in tank venturi design I am using now. Anyone have any experience with this type design?
Click to expand...

I suspect that its not quite as simple as a question about how "efficient" a design is, I suspect that a lot of it has to do with flow rate of the water through the reactor ...

I suspect that at least in my case, that the higher "dedicated" flow rate of the powerhead performs better than the flow rate of my Eheim 2028 canister filter did through the inline style reactor ...

Whether one "design" is more efficient than another, I don't know ... I just suspect that there are a lot of variables to take into account that may change from one person's setup to another ...

At least in my case, the Cornhusker variation of Tom Barr's Venturi Design sure is working wonderfully for me ...

Greg

P.S. Thanks to Cornhusker, he sent me a venturi reactor to test ...

AZFish1 · May 27, 2005

Re: Another stinking reactor question

Greg
Can you let us in on the adjustments that were made?

Anyone,

Have a good external venturi design to share?

PeterGwee · May 27, 2005

Re: Another stinking reactor question

I think Tom said he is coming up with one. We just have to be a bit patient I guess.

I'm still pondering over the response time issue as yet till now.. Tom always seem to get it(It takes about an hour or so to hit the good CO2 range.). He shuts the powerhead driving the reactor off during the night, meaning the pH will rise due to off gassing but the pH will fall into the good range again said 6.4 for a KH of 3 within and hour or so. I can hit the good range within an hour or so but the CO2 seems to keep rising pass the good range into higher unsafe zones which actually meant my CO2 rate is higher than needed I guess. I just couldn't figure it out why Tom's reactors can do it... . AZfish1, what was your max CO2 level that you got with Ghazanfar Ghori's designed reactor? How fast did the CO2 level stablized?

I sure hope Tom go into detail on this reactor use topic and perhaps an article on it since quite a bit of folks still couldn't figure it out. Detailed pictures of the reactor while it is running would be best...

Regards
Peter Gwee

PeterGwee · May 27, 2005

Re: Another stinking reactor question

Hi guys, was wondering how long it will take to return back to the optimal CO2 level after a large water change?

Before water change: pH-6.4, KH-3
After water change: pH-6.9, KH-3

Mine took about 3-5hrs to return the pH back to 6.4 with CO2 injection. Is it taking too long?

PeterGwee

Not at all, depending on how big your tank is. My 46 gallon takes 24 hours to settle.

GsMollin

quote:

============================
> With high GH and KH and pH tap water, a 40-60% water change is taking my
> CO2 down to around 5 ppm (or whatever normal ppm is without supplement).
> It takes about 1-2 days (sometimes more) for the pH to recover to the
> 7.1-7.3 range I try to keep it in.

A decent CO2 system would keep the pH in a good range within 1 hour or so.
If it takes days to hit a good range, how is it that the system is able to
keep up with the plant's uptake depletion rates?

CO2 is the biggest issue for you. And it will cause the most grief if it's
not well set up and responsive.
================================
Taken off APD and the response was from Tom Barr

In this quote, Tom mention it should take only 1hr or so to return back to the optimal levels....which is why I am asking this question. Any more response and personal experiences. Thanks in advance.

PeterGwee

I don't believe that. One hour is way too fast a response time in an aquarium. Not that you can't achieve it- With a pH controller and the bubble rate kicked up you can certainly dissolve enough carbonic acid to lower pH that much in an hour. Heck, in an experiment I performed some time ago, I lowered it more than that in one second!

Here's what's really going on: You dissolve the CO2 into the water of your aquarium, and then the plants take it up from the water. So you are not directly supplying CO2 to your plants, but to the water. Now depending upon how much water is involved, and the rate of injection, you get the response time of the pH in the aquarium. This has got nothing to do with plants, just the mass of the water involved. This is called the transient response.

After a time, you get to what's called the steady state. In the steady state, the pH is dependent on the injection rate minus the consumption rate minus the escape rate of CO2. So here is where you need to be injecting enough CO2 to satisfy the uptake of your plants and the amount that escapes from the water back to the atmosphere.

If you are using an open-loop system you will get a settling time in the 24 hour range. The pH will change more rapidly than that of course. You will see most of the shift in the first 6 hours, but it won't settle to the steady state until about a day.

If you want faster, get a pH controller, and you can sure speed it up, but do you really want to? I know I don't.
Click to expand...

I did a chat with GsMollin of AB quite sometime back while Tom was still around at that time with that forum regarding reactor responsiveness issue and that is what he came out with. What do you guys think? Is 1 hour responsiveness really impossible?

Regards
Peter Gwee

Greg Watson · May 28, 2005

Re: Another stinking reactor question

Originally Posted by AZFish1
Greg
Can you let us in on the adjustments that were made?
Click to expand...

I really can't ... it uses a side mount powerhead rather than a top mounted powerhead with a venturi loop, primarily because that was the equipment that was available/ordered. Without the venturi loop, it uses a rigid input tube as a substitute ... the construction is high quality and its working incredibly well.

When you work with the materials you have available, necessity is the mother of invention, and just because something is physically put together slightly differently doesn't mean that the function is any different ...

I would encourage you to build one ... you will not be disappointed ...

The only downside is the visibility ... often one of our goals is to remove as much equipment from the tank as possible ... so one of the BIG upsides of the external inline reactor is that it is one less piece of equipment in the tank ...

In my case, I have my aquarium to enjoy ... it may not ever win any design contests, so I am slightly less concerned about the visibility of the equipment in my aquarium ... And right at the moment, the venturi is installed in the front of my aquarium so I could easily watch it function while I was testing it ... its almost a centerpiece right at the moment ...

Greg

imatrout · May 28, 2005

Re: Another stinking reactor question

I think DIY is great and a fun part of the hobby. That said, I use an AquaMedic 1000 reactor on my 150 gal. tank. It's an external ractor that I have plumbed in-line with one of my return lines. The tank is soft plumbed with 3/4" hose, but the Reator 1000 only has in/outputs at 1/2" that I had to reduce. At first I didn't like it as it REALLY slowed down the return through the reactor, but as I've learned, the slower the better so it's a good aspect.

When I do a water change, the reactor will drop my Ph from 7.7 to 7.2 in a couple of hours hence I assume it's very effecient. I got it online for about $52.00. I realize that for some this is a lot, but considering multiple trips to Home Depot and the LFS for materials, material waste, searching for, ordering and waiting for specialty parts, I think you might just come out ahead buying one. I suppose that the design for the AquaMedic 1000, specifically designed for larger tanks, may have much different characteristics than other models and designs for different applications so what I say regarding the tradeoffs may not hold true for all applications.

Tom Barr · May 28, 2005

Re: Another stinking reactor question

PeterGwee said:

I did a chat with GsMollin of AB quite sometime back while Tom was still around at that time with that forum regarding reactor responsiveness issue and that is what he came out with. What do you guys think? Is 1 hour responsiveness really impossible?

Regards
Peter Gwee
Click to expand...

Apparently not.
24 hours?
I don't think so, I have grpahing data that shows my weekly water changes on a huge 350 gal tank(70% water changes) and it drops down rather quick(3-4 hours, I have high flow and good mixing, little cross flow).

A 20 gal with a good cO2 reactor should drop rather fast.

Also, see the here for some graphing:

http://193.12.137.241/bluesboy/pHplott.php?t=2004-12-26

Certainly about 5 hours for this particular tank. Not 24 hours as GsMollin suggested. This data does not lie. Unless GsMollin has a data logger, he may not see this. I have many months of data to suport my contention.

The DIY CO2 reactor pruges the gas after it reaches good saturation levels and spits out mist that escapes and off gasses. So it should not build up too much near the end of the day. I typically do the water change in the morning.

Other factors: timing of the water change during the day/evening. Water CO2 content, CO2 might be high as well as pH. Or CO2 might be low and the pH high.

If you look on the APC thread, you will see a large range of CO2 consumption rates. This is very difficult to measure with the testing equipment they are using and the methods chosen with any accuracy and the data is all over the place.

I think CO2 consumption rates need a labeled CO2 14C.
They make gas exchange equipment for Terestrial plants but adapting these for aquatic systems is not done from what I know.

This is tough stuff to measure accurately and perhaps beyond the realm of the hobbyists.

any other factors influence CO2 consumption as well..........unless those are accounted for, hard to say much.........you'll need a standard light unit/measurement as well. No one does that in the hobby except a few reef folks with LiCor light meters. These run 600-1200$.

Regards,
Tom Barr

Tom Barr · May 28, 2005

Re: Another stinking reactor question

You'll note Blueboy did a water change at 15:00.
The solenoid kicked on about 18:00 and dropped the pH back in about 3-4 hours.

regards, '
Tom Barr

Greg Watson · May 28, 2005

Re: Another stinking reactor question

imatrout said:

I think DIY is great and a fun part of the hobby. [...] I got it [commercial reactor] online for about $52.00. I realize that for some this is a lot, but considering multiple trips to Home Depot and the LFS for materials, material waste, searching for, ordering and waiting for specialty parts, I think you might just come out ahead buying one.
Click to expand...

I just got a message from Cornhusker, he has $14.25 in parts plus shipping costs in the Venturi Reactor he built for me to test ...

Of course, that doesn't count his time ...

Greg

PeterGwee · May 28, 2005

Re: Another stinking reactor question

Tom Barr said:

You'll note Blueboy did a water change at 15:00.
The solenoid kicked on about 18:00 and dropped the pH back in about 3-4 hours.

regards, '
Tom Barr
Click to expand...

Tom, so its not always within an hour? What if the lights were switched back "on" during that period and the CO2 levels are low? Does that cause BBA issues?

Regards
Peter Gwee

PeterGwee · May 29, 2005

Re: Another stinking reactor question

Ok, I just went through blueboy's entire site and found that the reason behind the drop was a CO2 rate cranked pretty high (look at the rate of the CO2 in a movie clip) and a pH controller to shut off once the pH is attained. With no pH controller setup and at that rate, the pH is definitely going to drop further. Running the CO2 at a lower rate I doubt is going to return the pH back to the good ranges within 5 hrs isn't it?

Regards
Peter Gwee

srozell · May 29, 2005

Re: Another stinking reactor question

PeterGwee said:

Ok, I just went through blueboy's entire site and found that the reason behind the drop was a CO2 rate cranked pretty high (look at the rate of the CO2 in a movie clip) and a pH controller to shut off once the pH is attained. With no pH controller setup and at that rate, the pH is definitely going to drop further. Running the CO2 at a lower rate I doubt is going to return the pH back to the good ranges within 5 hrs isn't it?

Regards
Peter Gwee
Click to expand...

I've been playing with my pH controller and found that it could take all day before the pH would reach a "good" range if I did gradual dosing. (30 bubbles a mintute in a 20 gallon tank.)

Finally I just cranked the CO2 to 60 bubbles a minute and I usually hit my target pH by 11:00 a.m.

Of course the higher KH, the longer this may take from what I understand.

AZFish1 · May 29, 2005

Re: Another stinking reactor question

I built it yesterday and set it up last night. I did it durring water change and cleaning time. I did not check co2 after water change because I leave the filter running and I am sure most is off gassed. After everyting was filled and running for three hours I tested and had 20ppm co2 (by the chart) by this morning (about 9 hours later) there is 30ppm co2. Exactly what I was able to get in those times with the venturi reactor. I made a couple small mods to the reactor that I will try to take pics of and post durring the week. Also I put it on the output side of the canister and not the intake. There is a bit of flow loss in the tank but I think I can live with it.

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