Do you think I need a CO2 defuser?

[DaveDude77]

Hi everyone,

I've got a planted 32G aquarium with 9 plants, 5 Danios, 2SAEs & 3wpg (2.5wk cycle). I was thinking that many plants would really saturate my water with O2. I think I've read somewhere that excessive O2 makes it hard on the plants but great for algae. And lately some brown algae has been growning on my plants and substrate, and most resently some green hairy algae as well.

So, I've reduced the light time from 11hrs to 6hrs (that'll help), but I'm still wondering about the CO2. Someone has told me that I don't need CO2 for a small tank, but does anyone else have any advice on this? This is my first tank and I've done a lot of research but no text references my tank exactly, that's why I'm asking you wonderful people here.

As for the research, my head is going to explode from all this info. :boom: BUT I LOVE IT!!!

[tbemis]

I am sure there are some more knowledgeable people that will post some comments, but in my opinion you could use a DIY setup for your tank. A DIY is more cost effective than a tank and diffuser, but using a pressurized tank and diffuser you can regulate the amount of CO2. I would suggest trying the CO2 to see if it helps (it did on my 20g and I was running 2 wpg). If you don't like the results or want more control go with the pressurized system. Hope this helps.

Trevor

[werner]

For the plants to saturate the water with O2, they need to take in CO2. You have enough light that CO2 addition would be beneficial. Here's a great article on DIY CO2. Your tank is a good size to use it on- not too big.

An alternative to CO2 addition would be to try Seachem's Flourish Excel. It's basically a carbon source in a bottle. Much less messy and time consuming than DIY CO2, but more $$. However, certain plants like vals may melt if it's used in higher doses.

[Drydock]

I don't use Co2 yet, (working on it) but I don't agree with the argument that a tank can be 'too small' to add Co2. I think the issue has to be looked at as supply and demand, not total volume. I can under stock or overstock a 10 gallon tank for the demands of my plants just the same as a 200 gallon tank...

A small tank is probably too small for a pressurized setup, but I agree with Trevor that you could try a DIY setup to see if it makes a difference.

I THINK that there are tables you can use and by testing your PH and KH, you can figure out roughly what your Co2 levels are. They may only give you a rough estimate, but it might be interesting to see what your Co2 level is in your tank now before you decide that's the issue.

your tank definitely does not sound overstocked, but how big are your plants? What types?

Edited September 4, 2008 by For Lack of a Better Term

[Drydock]

Found One...

http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html

The following table is from a finnish aquaria magazine (Akvaariomaailma)

When I was a beginner I did'n quite figure this up until I saw this

table, so maybe it will be helpful to somebody else too.

---

The relationship of CO2 , pH and KH

-----------------------------------------------------------------------

\ pH |6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4 8.0

KH\ |

-----------------------------------------------------------------------

0.5 | 15. 9.3 5.9 3.7 2.4 1.5 0.9 0.6 0.2

1.0 | 30. 19. 12. 7.0 5.0 3.0 1.9 1.2 0.3

1.5 | 44. 28. 18. 11. 7.0 4.0 2.8 1.8 0.4

2.0 | 59. 37. 24. 15. 9.0 6.0 4.0 2.4 0.6

2.5 | 73. 46. 30. 19. 12. 7.0 5.0 3.0 0.7

3.0 | 87. 56. 35. 22. 14. 9.0 6.0 4.0 0.9

3.5 | 103 65. 41. 26. 16. 10. 7.0 4.0 1.0

4.0 | 118 75. 47. 30. 19. 12. 6.0 5.0 1.2

5.0 | 147 93. 59. 37. 23. 15. 9.0 6.0 1.5

6.0 | 177 112 71. 45. 28. 18. 11. 7.0 1.8

8.0 | 240 149 94. 59. 37. 24. 15. 9.0 2.4

10 | 300 186 118 74. 47. 30. 19. 12. 3.0

15 | 440 280 176 111 70. 44. 28. 18. 4.0

-----------------------------------------------------------------------

| CO2 milligrams/liter

---------------------------------------------------------------------------

Edited September 4, 2008 by For Lack of a Better Term

[werner]

Unless you are actually adding CO2, your tank's natural levels from the atmosphere and biological processes will be about 3-5ppm.

[DaveDude77]

Thanks again for everyone's help. :thumbs:

Yeah, I was thinking the same thing tbemis. The DIY idea is cheap and I could always use it for another tank when MTS sets in.

Thanks for the link to the DIY CO2 thing, Werner. I actually had read it before. Great artical though.

That's a real interesting chart FTLOABT (sorry, your name is too long and an acronym is needed ). Do you know if these values are all relative? The reason I ask is that the last time I checked I had really low KH values and yesterday I tested my pH and it was 8.2. I'm wondering if this is in relation to the low KH values and the possible low CO2 values. If so, then I should probably add some CO2 to help keep the pH down if nothing else. I'll have to wait a while first though because I just reduced the amount of light my tank gets and that should lower the O2 levels itself, right?? I understand that plants consume O2 at night. Also, I guess some of these strange numbers may be that I'm still going through my cycling stage.

AHH!!! to many variables. I can't wait for my tank to finish it's cycling and stablizes so I can really feel good about the water tests, CO2 values, yada, yada, yada. But PLEASE keep the info coming, the more the better.

Oh, one more thing. Does anyone know if it's true that Algae just loves excessive O2?

[uwish]

Just keep in mind those tables can be misleading. There are calibrated assuming ONLY carbon as the buffer in the solution.

As soon as there are other buffers present these tables do not apply.

CO2 levels can be monitored nicely by using a drop checker which are 'relatively' inexpensive and much less subjective. Plus you do not 'need' to know your GH or KH levels to use them effectively. You do however, need to have a KH of greater than 4 I think. At least mine does. Hence if you have a water softener it can cause some issues in the measurement unless you use un treated tap water.

cheers

Edited September 4, 2008 by uwish

[werner]

Oh, one more thing. Does anyone know if it's true that Algae just loves excessive O2?

Never heard of this. You can't really monitor orcontrol O2 anyways, so don't worry about it.

The best way to control algae in a planted tank is to keep the plants growing well. Plants and algae need the same nutrients to thrive. Since algae are nutrient scavengers and much simpler life form than plants, they will take an advantage in tanks where there is an imbalance between light, CO2, and nutrients levels that inhibit the plants.

If your tank is still new and cycling, don't worry about the algae yet since things will be out of whack for a while. The brown algae (diatoms) are a normal occurrence for new tanks and should go away on their own.

Read more about types of algae and their prevention here

Has your head exploded yet?

Here's more on the pH/KH/CO2 relationship

[DaveDude77]

Thanks again people. You are all great for helping myself and others out. I hope that I can become as knowledgeable as you all so that I too may be able to help others in the future.

Well, it's off to read those links. Thanks werner.

[Ruadh]

With a DIY set-up it's difficult if not impossible to control or measure CO2,

but with a bottle of gas and a proper regulator with a solinoid, it's a piece of cake.

I used a differential PH calculation the establish my CO2 level.

Take the PH level of your tank with the CO2 running about 2 bps for a day or two.

In the mean time, take a sample (a cup or so) of the tank water and let it sit over night to let the CO2 out-gas.

Compare the two readings and if there is 1 degree of difference, the CO2 water being the lower of the two, then you have close to 30 ppm of CO2.

Adjust the CO2 accordingly to obtain the 1 degree differential.

This is basically what you do with the drop checker, but I, myself, think it's more accurate to do the PH readings.

Also, if you want to spend the money, you can use a PH controller to control the CO2.

Rather, you use the CO2 to control the PH. The CO2 will stay at a very stable level, once set.

Rick

Edited September 4, 2008 by Ruadh

[jvision]

I'm from the KISS school of planted tanks. I haven't owned a test kit for years, I grow plants like crazy, and have minimal algae problems. I use the Estimative Index method of keeping plants. There is a dosing chart for the EI at the end of the articles thread in the pinned topics here in AA's planted forum.

If you Google Estimative Index, you'll likely come across a guy name Tom Barr. He's discovered a lot of great things about keeping plants - if you find any of his material, it's a good read.

[byte]

That's a real interesting chart FTLOABT (sorry, your name is too long and an acronym is needed ).

FTLOABT sounds like something the gov't would use in a web address...

Just keep in mind those tables can be misleading. There are calibrated assuming ONLY carbon as the buffer in the solution.

The CO2 charts are calibrated assuming ONLY carbonate as the buffer in the solution.

This is basically what you do with the drop checker, but I, myself, think it's more accurate to do the PH readings.

A drop checker is basically a real time pH monitor... As the CO2 goes higher or lower, the liquid changes color as the pH moves up or down. The drops used in a drop checker as the same chemical in a low range pH test kit.

[devocole]

Thanks for all the tips guys. Its helped me out too. I especially liked the link to the algae page werner. I'm going to be starting my 50 gallon planted within a month and will need everyones brains as well.