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Co2 and ph

C

Craig Matthews

Member
Joined
21 Oct 2018
Messages
240
Location
Yorkshire
I've got a co2 kit coming and I live in a very hard water area so I've been using 75% to and 15% tap ive got my ph down for sometime now and is currently reading 7 on a liquid test. When I start dosing the co2 people say aim for a 1ph drop? Is that only for the duration of the lighting period then after lights out it should raise 1ph again? Does the up and down of pH everyday affect fish? It's only a 70 litre maybe I should I'm for 15ppm? Just Val's,sag,crypt,hygrophila syamensis and anubias in there ATM.
Thanks in advance.
 
Craig Matthews said:
I live in a very hard water area so I've been using 75% to and 15% tap
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75% of what ????
Water hardness makes no difference to fish or plants, unless you are after specialist fish or very fussy plants just try to work with the tap water you have got. My water is 22' (very hard) and fish spawn and plants grow, just preheat water, add dechlorinator and add to tank. Done.

The 1pH drop, is as measured by a pH probe, not a test kit, as test kits will be influenced by other ions present in the water. A pH drop of 1 unit indicates that about 30ppm CO2 is present. Provided the water is not super soft (ie anything above 4dKH, so hard water an advantage) then adding 30ppm CO2 will drop pH by one unit. Again fish and plants don't care as this is pH changes over time and using weak acids. Fish probably encounter bigger pH swings in the wild due to natural water changes.
You need to obtain this pH drop by the time your lights come on and the plants start requiring CO2. This pH should remain steady for the lighting duration, thought generally most people turn CO2 off an hour before lights off. This will require much mastering of the fine art of CO2 injection to get it right and reliable. I run an air pump before lights go off to degas any remaining CO2 and also has the effect of stirring up any settled detritus to get filtered away.
 
75% ro water.
Aha ok so trial and error I've got a drop checker coming too do I literally just add co2 until the liquid is green obviously it can take a couple of hours to change colour? I will stop wasting my money on ro water then it's full of minerals anyway benificial.
 
Just dechlorinate your water and maybe warm and you are good to go.

I start injecting CO2 2hours before lights on and have a green/yellow drop checker by then. Stays that colour i.e. stable CO2 all the time. Unstable/varying CO2 levels (normally caused by people poor distribution and flow) causes poor plant health and associated algae outbreaks.

If you don't have fish whop injection up and see what drop checker does two hours later. Then back it off the following day and further days until drop checker is green.

If you have fish increase CO2 rate slowly over a period of days till you get a green drop checker at lights on.
 
Ok I will do, drop checker came yesturday the JBL plus ph2 it has a pH colour chart refering to the kh which shows different varieties eh,kh4,kh8 and kh12? Is it very important to test for oh or can I just use the co2 mg/l colour chart? I will add very slowly maybe start with 1 bubble every 2 seconds
 
The colour mg/l and kh
 

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Just use the CO2 mg/l chart. Basically you are aiming for green.

I think the other charts are for the older JBL test kit that used tank water in indicator. You basically measured your KH and used the corresponding chart depending on your KH value.

This is too far.
upload_2018-11-15_11-59-50.png


Maybe slightly too far ?
upload_2018-11-15_12-0-47.png


Just right.
upload_2018-11-15_12-8-32.png
 

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Ok cool well I've just set it up got the reg/solenoid delivered today it's been running a couple of hours the drop checker is yet to change. I'll adjust accordingly just can't decide on the best place for the diffuser. I've got it under the outlet so see how it goes.
 

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ian_m said:
I run an air pump before lights go off to degas any remaining CO2 and also has the effect of stirring up any settled detritus to get filtered away.
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Sorry to hijack your thread.
@ian_m could you explain a bit more about why you degas your tank? I am just setting up my rescape and have a pump and timer doing nothing if this is beneficial to tank I could setup.
 
Its a good idea to have lights on hour or two when CO2 photoperiod is off so plants uptake remaining CO2, in water column,as the reverse happens with lights off -plants releasing CO2 so using a airstone at night balnces this degassing CO2. This is what Ian means
 
Carpman said:
@ian_m could you explain a bit more about why you degas your tank?
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The air coming on at 22:45 to 2:15am (lights off at 23:00), in my case, performs multiple functions:
  1. Degas CO2, which may or may not be beneficial to plants & fish. Drop checker is certainly heading "off green" after only 15 minutes of air.
  2. Causes a change in tank water flow patterns and lifts any settled detritus into the water to be filtered away. I have an air curtain tube across the back of my tank at substrate level. Works well.
  3. Clears any water surface film, that we actually haven't got, as our plants are healthy. But if we did...:rolleyes:
  4. Informs me slobbing on the sofa that it is getting late and really should be considering going to bed.:grumpy:
 
It will also give your tank more stable O2 levels as it compensates for the O2 being produced by the plants only through the potoperiod, But ever thing else filter bacteria etc uses O2 24/7 so will give more stability to the tank envioment.
 
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