D.C changing colour

Discussion in 'Carbon Dioxide (CO2)' started by Dolly Sprint 16v, 4 Jul 2009.

  1. Dolly Sprint 16v

    Dolly Sprint 16v Member

    Messages:
    1,611
    Location:
    Cheshire
    Gang@ukaps

    During no lighting time the D.C on the right hand side of the tank looses its colour, the D.C on the left hand does not loose as much colour, I know the reason why the right hand D.C has a loss of colouration. The Co2 clicks into action two hours before the lights come on and both D.C are showing lime green at the point that the tank lights come on and are the same colouration when the lights go off - should there be any need for concern that the water column looses its residual Co2 thus showing a pale blue D.C. The left hand D.C does show a slight difference in its colouration but not as much as the right hand D.C. The funny thing is that there has been a very slight break out of green spot algea on the glass on the left hand side - this would indicate a lower flow / circulation than that on the right hand side, but there is more Co2 within the water column on the left hand side of the tank as the D.C is showing a grass green colour when compared with the D.C on the right hand side which is showing pale blue.

    Any thoughts

    Paul.
     
  2. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    CO2 distribution in a tank is never homogeneous for many reasons so it's unsurprising that dropcheckers mounted at different locations behave differently. GSA is also a low PO4 indicator as well as a low CO2 indicator which sometimes makes troubleshooting tricky. On a covered tank, normally the residual dissolved gas levels are maintained quite well and the checker typically stays in the green. If it's turning blue that might suggest an injection rate increase, although one has to decide whether higher gas rate is worth it. If growth is good, the water clear and algae is negligible then driving higher growth rates and risking toxicity via higher injection may not be advisable.

    Cheers,
     
  3. Dolly Sprint 16v

    Dolly Sprint 16v Member

    Messages:
    1,611
    Location:
    Cheshire
    Thx clive

    As i stated previously the strange thing is that where there is retention of co2 within the water column (green D.C) and a slight break out of gsa, I tested tank water inc. tap water the other week for Po4 levels both readings were 5.0 mg/l, as far as I am aware there are two ways of reducing Po4 - increase Nitrates which would increase nitrites (dangerous) which would reduce Po4 levels or bag of Rowaphos within the filter - but this product would remove all Po4 and Po4 is required within the water column as it ia a macro nutrient.

    Which is better to retain Co2 within the water column or allow Co2 to escape from within the column during non tank light hours :?: .

    Regards
    Paul.
     
  4. Graeme Edwards

    Graeme Edwards Founder Staff Member

    Messages:
    1,161
    Location:
    Wirral/Chester Cheshire.
    Hi Paul,

    If it were me, i'd find a space at the opposite end of the tank away from your diffuser to host your drop checker. Find the happy medium by getting the color to what you want. I aim near the yellow if the fish are ok with it, but if your not happy with that, then stick to a pale green.

    Green spot can be down to Po4 deficiency and I have found adding Po4 when using RO helped to control and eliminate green spot.

    If you want to get rid of the Po4, why not change or add a few fast growing plants like Hygrphila Difformis or alike.

    Cheers.
     
  5. Dolly Sprint 16v

    Dolly Sprint 16v Member

    Messages:
    1,611
    Location:
    Cheshire
    Graeme

    i do not have a diffuser within the tank - in line reactor on the output side of the filter unit. This issue of different coloured DC has only happen since I refitted by sprinkle bar if you look in the very top left hand side of tank you will the bar, bar removed tonight. If you cast you mind back about a few week we had a discussion at the TGM in relation to Po4 and I sent you a pm readings of tank water v tap water. One thing I can say it that the Rosanervig I bought is doing fine. Picy attached regard tank status as of last night.

    DSCN3403.jpg

    DSCN3405.jpg

    DSCN3404.jpg

    Regards
    Paul.
     
  6. baron von bubba

    baron von bubba Member

    Messages:
    333
    Location:
    stroud, glos
    erm, are you not incorrect in thinking this?
    nitrAtes don't increase nitrites.

    and wouldnt adding nitrates only decrease PO4 levels if the plants were nitrate limited?
    in which case you should be adding nitrate anyhoo

    how would you go about retaining co2 at night?
    i guess pretty much the only way to do this would be have very little or no surface movement?

    as long as the levels are acceptable when lights come on, then how much you lose at night will make no difference to anything
     
  7. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    Yes, this is a valid assessment. Nitrification occurs in the sequence NH3=>NO2=>NO3. Therefore, increased nitrites result in increased nitrates not the reverse as stated by the OP.
    Well, there is an indirect correlation between uptake of these two in this direction. The effect of increased Phosphorous uptake is an increase in the uptake of Nitrogen.
    As mentioned earlier, covered tanks retain a goodly amount of CO2 but this amount cannot be judged solely on the dropchecker color since it's response may be a lag time of around two hours or so. Open tanks, such as those using luminaries or pendant lighting tend to retain less CO2 overnight. Some people use airstones to purge residual CO2 levels overnight to help give the fish a break from these residual levels, so tanks do retain certain levels. The advantage with that is it takes less time to bring the concentration up to the required levels prior to the photoperiod.

    Cheers,
     

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