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Does anyone know the maximum GH/KH of water so that CO2 can disolve?

Planted 42g Hex.
132W PC 6700K.
NH3 = 0
NO2 = 0
PH = 6.8
Running compressed CO2 with a membrane diffuser.
My "Red Sea" CO2 indicator used to turn green w/ 5-6 bubbles per minute. I did about a 40% water change and now I can't get it to turn green again. I've increased CO2 to 12 bubbles per minute now with no change in my Red Sea indicator and I've noticed a significant slow down in the growth of my plants. I am only guessing that my GH/KH is now to high for the CO2 to disolve.

I don't know anything about CO2 indicators and whatnot, but you need to pump more CO2 than that. 12 bubbles per minute is awfully little for a tank with ~3 watts per gallon. You should aim for more like 2 bubbles PER SECOND to get levels up where they need to be, possibly even more. When running CO2 on my 26 gallon I was pushing around 3-4 bubbles per second to get proper saturation. CO2 is limiting plant growth right now with that amount of light.

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Back in the saddle!

The "membrane diffuser" is much more efficient than the other types. I was getting "pearling" from only 5-6 bubbles per minute...even from my Anubia Lanceolata at the bottom of my tank. My GH/KH test kit was delivered today. I'll test tonight and post results of those test.

Another testament to the membrane diffuser and this is actually how I learned about it. I have a friend that has a 45 gallon tank with 192W. He was running 8 bubble per "minute" (NOT per second) and his tank looked like an alka selzter!

http://aquatic-store.com/en-us/dept_27.html
I have the 4 chamber diffuser.

Test Results:

KH = 5 Degrees German (not quite sure what that means exactly.)
GH = 2 (I think that is a little low???)
PH = 7.0

According to the chart that I have that gives me 16ppm of CO2 which again I think is a little low. Can anyone give me an idea of how to correct this problem by adjusting the GH/KH? I think 12 or less bubbles per minute with the memebrane diffuser will give me a higher CO2 level, I just don't know how to adjust the GH/KH correctly. All input is greatly appreciated!

The CO2 indicator that I have monitors my CO2 with a chemical reaction that is indicated by the color of the liquid.
Blue = low CO2
Green = Ideal
Yellow = to high

The chemical is contained in a plastic bubble that suction cups to the inside of the aquarium. CO2 enters and escapes through a hole in the bottom of the bubble.

You can't get more CO2 by adjusting your KH or GH. If you add buffers, your pH will rise and you're left with exactly the same CO2. KH and pH are a method of measuring CO2 in your tank, not a means to increase it. Like nowherman wrote, to have more CO2 in the tank, you must put more CO2 into the tank. It's really not as complicated as it sounds. I'd start with about 1 bubble per second and work up from there. Even the best diffusers/reactors can't make something from nothing.

Oh and those CO2 measuring jobbies don't last forever. I think about a month is the life expectancy. Yours is most likely done for. Just stick with pH and KH test kits to measure CO2.

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Critical Fertilator: The Micromanager of Macronutrients

CO2 Indicator Pic: [/img]

Attached Image:

I change the chemical agent about every 2 weeks...3 weeks maximum. According to the KH/PH my CO2 is already at 16ppm. If I go up to even 1 bubble per second my CO2 level is going to go through the roof. Also according to the chart if I just lower my PH by 1/4 of a point to say 6.6-6.8 my CO2 would be at 33ppm.

I guess I will try raising my bubble count to about 20 bubble per minute and recheck KH/PH tomorrow.

Putting 3, 4, 5+ bubble per second just seems like so much!
Especially when I was getting pearling from 6 bubbles per minute just 2 weeks ago. And my friend is getting an incredible amount of pearling in his 45gallon tank at 8 bubble per minute. His glosso looks alka seltzer!

I've only been doing this for about 6 months now...so I would say I am very new to planted aquariums!...but I thought that the "buffers" allowed more or less CO2 to be disolved into the water column. High carbonate hardness increases the buffering effect not allowing the CO2 to dissolve....and vice versa???

Things other than CO2 have a factor in pearling. Plants need all the other nutrients for photosynthesis. Nitrate, phosphate, and potassium are the major ones. Micros should be dosed as well. Light and CO2 is just part of the equation.

Go ahead and put the thoughts of altering pH/KH out of your head. It doesn't work that way. They are only a tool to measure, and IMO the best monitor for CO2 is your fish and plants. If your fish aren't gasping at the surface, then you don't have too much CO2 in the water. If you have some algae or your plants aren't growing fast turn it up. If your lights and CO2 seem to be right in order, and you are still having problems, then you will need to start dosing the other nutrients. With high light and CO2, you should go ahead and assume that you will need to be adding nitrates and phosphates.

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Critical Fertilator: The Micromanager of Macronutrients

Welcome to the fun of figuring out CO2!

The higher the KH the more stable your PH is going to be. It the world of CO2 this mean that if you have a high KH you are going to have to work harder to lower your PH. Thus adding more CO2.

In my case I have a PH of 8.2 out of the tap and a KH around 16-17. I have no idea what my bubbles/minute or second are but the CO2 is blasting. I aim for a PH of around 7.0 at night which gives me a bit over what I really need for CO2.



55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

I dose with Flourish twice a week, and supplement my poor substrate with Root Tabs. I only have I didn't plan on doing a planted tank because when I bought it I didn't have a clue about it. It literally grew on me...and helped my wallet to get a little lighter as well.

Anyway my:
KH = 5
PH = 7.0 yesterday
On the chart that gave me 16ppm of CO2.

I increased the CO2 to 30bpm which more than doubled last nights output. I'll check it in a few hours to see if my PH has crashed! LOL Here is a pic of my 42Hex...interested in thoughts and criticisms[img]

Attached Image:

That's a pretty nice looking tank there. From the looks of it, there's not much doubt you are getting your NO3 and PO4 from fish waste, but that's something you might want to add a little bit of to be sure.

What was the pH reading after the increased bubble count?

The other thing I noticed is that you don't have a lot of fast growers(the only one I saw was wisteria), which will limit the amount of pearling you will see IMO.

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Critical Fertilator: The Micromanager of Macronutrients

Your tank looks pretty lush! Could you take a shot from a distince? How long has it been set up?

Just a word of causion. The more light and CO2 in on and in the tank. The more ferts you are going to want in there too. Light and CO2 are your major limiting factors for plant growth.



55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

With 36 bpm my PH dropped to 6.6-6.7, KH measured out at 5.5. That gave me about 33-41ppm of CO2. It was enough to turn my CO2 indicator green within about 5 hours and yellow (to high) within about 8. I scaled it back down a little to about 25bpm and the indicator was green this AM.
I'll see how it does with a full day of light when I get home from work.

Matt: You are correct about the limited fast growers..the only other one other than the Wisteria that you noticed is a bunch of Anacharis that was out of view.

Wings: My tank has been running for about 8 months now, with plants only about 6 months. The tank was originally bought with the idea of just having fake plants and fish, but one plant here and then another plant there....then DIY CO2 threw an air stone...then finally PC lighting and compressed CO2 w/diffuser. In it's current state it's been going about 3 months. A big problem that I have is the substrate is just gravel and there is an undergravel filter. Another problem is that my tank is a Hexagon...I don't have a hood so I just have a glass top with a Coralife 96W quad on it with two 18W PC fixtures to supplement the front and back. I did some measuring and when I move I will try to build a hex shaped hood and I think I can take the Coralife apart to mount just the ballast and reflec/light. In that config. I think I can mount two of those if I can come up with extra $120! I hope to be moving in a few months at which time I will set the tank up correctly...and I've had my eye on a 150g 60x24x24! I'll try to take more pics 2nite.

hat gave me about 33-41ppm of CO2

That is pretty ideal for your CO2. Mine gets even higher than that and I don't have any problems. I also have a very high KH so my PH never crashes.

55G Planted tank thread
19G Container Pond
[IMG]http://i4.photobucket.com/albums/y118/Wingsdlc/Ric

Yeah, I agree. You should bump that right back up to your 36 bubbles per minute or whatever you had it at to get 30 ppm CO2 or above.

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Critical Fertilator: The Micromanager of Macronutrients

Thanks for the info guys! Bumping the CO2 bpm back up is no problem. I have another question though...if you don't mind. Although my KH seems to be ok at about 5.5 my GH is almost non-existent. With the test kit I have it indicates that my GH is <1. Should I try to get this back up? I was going for a softer water aquarium bcus I have Angels, but I have 15+ shrimp as well; that I am sure need the minerals/calcium for molting??? I think I ran the water softening pillow a little to long.

I have a 5lb CO2 tank...any idea how long that should last with 35+ bubble per minute? Do you use a solenoid to turn CO2 on/off for day/night? I have a solenoid, but choose to just let the CO2 run constantly.

Hi dmarkham0117

Firstly, your tank is looking really nice. Good job.

I agree with all the advice you've been receiving and these good people helped me get my C02 up & running too. I probably run just over 2 bubbles per sec. Some people do run their C02 24/7, but I think plants only use C02 when lights are on. I've heard also that if you run C02 at night, you should use an airstone (don't use an airstone when lights are on - I think it will dissipate C02 - but others will let you know if I've got that wrong).

BTW, has anyone given you this link yet http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm Sorry if it's a duplication, but I found it helpful when the guys here passed it onto me. It's a calculator of measuring CO2 levels in a planted tank & also explains about the kH myth.

This link helps work out your ferts http://www.csd.net/%7Ecgadd/aqua/art_plant_dosage_calc.htm. Here's another that might help too http://home.iprimus.com.au/clintbrearley/barr.htm

I think most of us with a solenoid do use it & they're set up to co-incide with the lighting sequence. My gas bottle is only small & it is a 35min trip to refill, so I prefer to use the solenoid.

Keep up the good work on your tank. As said, it's really pretty.

Cheers
TW

Forget about using the Co2 indicator. They are inaccurate and really only intended to give a quick eyeball of what's going on the tank. The fish will give you a better idea. If they are comfortable , ie not gasping, the Co2 level is not too high.

With your KH a pH of about 6.6 is just fine. When adusting Co2 slow steady increments are better. Suddenly increasing Co2 by 50% will drop the pH too fast and may stress the fish.

GH should be at about 3 dgh to ensure sufficient calcium and Mg availability. Use Seachem Equilibrium to do this. It's easy to dose.

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