Another way to determine CO2 in our tanks

[izzat]

Have yet to run my new tank

When I had my 3 month 1ft tank, I did 30% weekly water change and pH measured was 5.5
As for KH, I am not too sure as I did not measure and I was not using CO2 for that tank.

In the case when my tank has no Fauna but only Flora, will the Flora be affected by the pH crash?

[vinz]

A word of caution: make sure that the water at ambient CO2 levels is at ambient CO2 levels. Letting it sit idle for a day does not gaurantee that the sample has diffused enough CO2. Stirring and aerating will help ALOT.

If the target pH is too low, raise KH first, then repeat the test.

[Patrick76]

I am setting up a new tank with ADA aquasoil. I assume the pH of the tank will be low with aquasoil. I intend to add in bicarbonate to increase the KH as well as the pH to 8.2-8.5 and then use CO2 to lower the pH to 6.5-6.8. The drop in pH will be approximately 1.7 which correspond to about 30 mg of CO2 in water.

Do you guy think the above is the correct way?

[Shadow]

pH and kH lowering is ADA aqusoil feature, IMO what you are doing is a waste. Adding bicarbonate probably will increase the kH for a while and back to zero the next day, until you depleted the kH lowering capability of ADA aquasoil. Don't worry about the pH, it will stabilize to around 6.2 once you completed your cycle.

[milk_vanilla]

so your intention is to increase the KH level, in order to short down your PH drop swing when you hit 30mg target CO2 ? 1.7 PH drop is too high , it might impact your fauna.

Mine was 6.8 PH during CO2 Off, and 6.3-6.4 during CO2 on. KH around 3-4 dKH.

[Patrick76]

I read in earlier post that a drop in pH of 1.7 is equivalent to 30-40 ppm of CO2 in water. Is this the optimum level to maintain?

Hi Shadow,

I am cycling the tank now. You mean that once you complete the cycle, it will stabilize at 6.2? If I am going to perform the above action after I complete the cycle, does it helps?

[Shadow]

yes it will stabilize to 6.2, currently probably your pH is around 5. You really no need to do all those action.

[Patrick76]

I have set up a low tech (non-CO2) tank and it is now going to 2 months (including 1 month of fishless and plantless cycle). I started to see some green spot aglae growing on the front and the back walls of the tank. I read in an article that green spot aglae will grow if CO2 and PO4 levels are low. I dose in my Lushgro fertilizers faithfully every alter days so I don't think that PO4 is an issue. Henceforth, I think that CO2 could be the cause.

I read in Tom Barr's report that plants do have these CO2 fixing property. I am just wondering if it could be due to this property which lead to low free CO2 in the tank. I guess KH is also an important factor as it helps to keep CO2 stable in the water.

I would like to try to maintain a certain concentration of CO2 in the tank and see if the green spot aglae goes away.

Please correct me if I am wrong.

Thanks.

[Shadow]

I don't think is that simple. I have yet to see green spot algae disappear by increasing CO2 and PO4, normally it will disappear when you reduce the light. That make me wonder, green spot in low tech tank? When you said low tech tank, I hope you are referring to low light.

[milk_vanilla]

Sometimes green spot likes direct sunlight, i used to have minor green spot in my front glass, where i have direct sunlight across my living room window. But it's minor, so i don't take this a serious matter

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[Patrick76]

I don't think is that simple. I have yet to see green spot algae disappear by increasing CO2 and PO4, normally it will disappear when you reduce the light. That make me wonder, green spot in low tech tank? When you said low tech tank, I hope you are referring to low light.

I have a 20W light over a 60 litres tank. Consider low tech right?

[Shadow]

20W that low enough to be considered low tech, maybe for your case P and CO2 can work. Any direct sunlight during a day like what milk_vanilla said?

[AQMS]

This is the topic i am looking for KH and Ph.
I have been reading about it but still kind of unsure.
Shadow, my planted tank has 8dkh and ph 6.8.
what does that tell you?
Is there a table that i can refer to?

[Patrick76]

20W that low enough to be considered low tech, maybe for your case P and CO2 can work. Any direct sunlight during a day like what milk_vanilla said?

It is near a window but the window is always closed. I am trying Seachem Excel now. Hopefully it can work.

[AQMS]

Just checked my kh.
its 12dkh and ph 6.8
the previous data was wrong.

[milk_vanilla]

Wow! you have 12 dkh, that's interesting... what kind of water you fill your tank with?

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[AQMS]

Normal water.....aka tap water
Is it ok at 12dkh? i am really not sure.
I never check for kh before, i bought the test kit because im just curious
how it works...
Can someone explain?

[milk_vanilla]

I read somewhere Some plants species may have stunt growth affected with high kh watery, if you curious you could test it by your self by lowering down the kh and see if there's growth speed up. And return it back up slowly, till your comfortable level.

But again, i did not say that dkh 12 is bad.

I never had 12 dkh watery level at the moment, mine is 3-4 dkh

[AQMS]

yup, i read about that too,
my tank is about 4weeks old, i just rescape it.
So far the plants i see no significant different because the new ones are still short
and the old ones from my previous tank probably same size.
i know you did say 12dkh is bad but u sound surprised.
Anyway how do you lower kh?
Will it effect my ph?
I think so right?

[milk_vanilla]

Mix the tap water with ro/di water will lower your kh. But it sounds costly if you running in big tank.

The other option probably is using chemical like seachem acid buffer, or sort of. But i never try using this before. Sometimes I feel guilty to the living creatures i have, by dumping lot of chemicals out there

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