Mazzei and Discus

[iwantdiscus]

Does anyone here run a mazzei to distribute CO2 and have discus? Do you use a ph controller? How do you measure for CO2? test kits, brand etc............

[scolley]

I do. I use a Mazzei with a pH controller. Not sure why you would ask about using these with discus, vs. fish in general. Maybe concerns about big pH swings caused by the low KH water that discus prefer?

My KH is typically around 1.2. Pretty low. And I do get swings using the Mazzei. Typically around 0.1 to 0.15. The Mazzei is so efficient that by the time the CO2 injected water circulates such that the probe sees the change to shut off the CO2 solenoid, there is still more CO2 enriched water yet to circulate to the probe. In other words, by the time the pH drop is detected, there has been enough injected to guarantee that the tank is still going to drop a bit more.

I suppose I could turn down my needle valve to restrict the flow to the Mazzei a bit more, but frankly the fish have never seemed to care.

You can check out a diagram and explanation of how I have it rigged here (http://wetplantlogic.com/wordpress/http:/wetplantlogic.com/wordpress/2008/06/07/tank-plumbing-technical-diagram/). And over at Plantedtank.net, there is a major thread somewhere on how to size them. Just do a search on Mazzei.

I have to periodically recalibrate my probe using a 2-point calbration with 4.01 and 7.01 solutions. At the same time I also recalibrate a Hanna electronic dip type probe. Testing them both against each other, using the 4.01, the 7.01, and tank water gives me a real sanity check.

For a probe I use the Neptune Systems Lab Grade probe. They are a good bit more expensive, but IMO much more accurate, and do not drift (need recalibration) nearly so often. But even then I'm lazy. I find calibration a PITA, so I've recently put a two bulb drop checker (http://www.plantedtank.net/forums/cal-aqua-labs/63704-new-double-check-co2-checker-cal.html) into my tank just to give me a visual. If the probe starts drifting, I can see it in the drop checker. And rather than going to recalibrate my probe, it's just SO much easier to adjust the pH level my controller is targeting. I know it's a little off in it's reading, but from the drop checker I know the CO2 concentration is actually correct.

Hope that helps.

PS - In low GH/KH water, or water with low TDS and other conductive materials, electronic pH probes have a tough time being accurate. So don't panic if you get different readings with different probes (even after calibration). Just verify with a chemical kit (or drop checker) and learn to compensate accordingly.

[iwantdiscus]

Thanks Scolley, I am worried about the ph swings for discus, if it was just regular typical fish, I wouldn't be so much. I have seen and read the entire mazzei thread at planted tank, thanks. But they talk about gassing the fish is easier because the mazzei is so efficient, and the last thing I want to do is gas $100 fish. These discus cost more than my saltwater friends. Haven't quite setup the tank for discus yet as I currently have a planted 75g, not big enough for discus and me IMO. Am trying to find out all I can about discus and plants, other freshwater fish and plants are easy, throw in some water and plants, good to go, well, maybe not that easy, but pretty close. I have closely read the pump journal on this site from diablocanine, what do you think about the way he has gone about that?.......thanks again Scolley, have learned a lot about discus from this site already............jeff

[scolley]

have closely read the pump journal on this site from diablocanine, what do you think about the way he has gone about that?Jeff I'm not familiar with the journal that you are referencing. Diabolocanine is one of the better informed people over at PT though. Like myself, he is inclined to get more aggressive with plumbing than is really necessary. But he is a perfectionist, not afraid to try new things, and happy to share them. So he gets a real thumbs up from me, without having read that specific thread.

The only thing about a Mazzei, vs. more traditional methods of CO2 enrichment, is that if your system fails - does not shut off - your fish will be dead in no time. It's not like you're gonna be able to fix stuff when you get home from school or work. If that thing has been going uncontrolled for a couple of hours your pH will have dropped 4-6 points, and your fish will be toast.

I don't know how fast those things work, but if sized correctly it's really fast. I'm going to estimate that mine could drop my pH from 6.5 down to 5.5 in about 15 minutes. And that's in a 180g. Again, you can use a needle valve to throttle that back, and provide yourself more breathing room. And the more I think about it... I think I'm gonna go cut my bubble rate in half, maybe even by 75%. Right now. ;)

[iwantdiscus]

Thanks for you input Scolley, but Diablocanine's sump journal is under planted show tanks and biotopes on this website(sump journal sort of). My CO2 is running fine right now, but I use a bubble diffuser, I also have a sump with minimal splashing, and don't know about CO2 levels, everything just looks to be growing well and fish don't gasp for air, Had to take out the bubble counter because it kept leaking, I just view the bubbles the diffuser is releasing into the tank. I also have overflow filtration and won't ever go without one. Current tank has operated with it for 6 years now, I never lose any fish, some are 6 years old, and if I ever have to change to marine you have to have sump and overflow, IMO.....

[iwantdiscus]

My only reason for asking is if all the fish in my tank died of CO2 gassing, I'd be out about $75, if I lose a tank of about 10-12 adult discus, I think I could be out anywhere from $1000 to $2400+, I am just concerned about a huge change or swing that I keep reading that discus don't like......If there are going to be problems, I'll just stay with a glass diffuser.....