pH / kh question for new tank

willgaze

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12 Jan 2009
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I am three weeks into cycling my heavily planted tank, with ADA amazonia substrate. The dropchecker stays bright yellow all the time (dKH 4 water), whether the co2 is on or off. Should I be worried about this, nitrates are high but the colour doesn't change after 50% water changes every other day. My pH test strips say 6.4 but they only go down to 6.4 so am am unsure whether I should be trying to raise KH (normally 3), reducing co2 or both.
Many thanks
 

Themuleous

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In terms of the Co2, it is odd that it stays yellow even with the CO2 off. How long do you leave it? It can take several hours for the CO2 level to drop and the DC to show the resulting colour change.

As for the pH, bin the test strips. They aren't very accurate. In any case, the AS will probably have sucked all the KH out of the water so the pH is likely to be much lower than 6.4. Also, I cant say Ive used AS but it is reasonable to say that the NH3 leached has turned to NO2 and then that to NO3 so you'll have lots of NO3 floating around :)

Sam
 

willgaze

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Thanks for the advice. The co2 goes off at 22.00 and comes back on at 14.00 the next day. I will buy a more accurate pH test kit and perhaps try and raise KH if it is too low. There is no sign of the filter improving no2 - no3 (I lknow it's only 3 weeks) so perhaps the cycling has stalled due to excessively low pH.
 

willgaze

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One further quiery, I've read on other threads that ADA amazonia strips KH, should I worry about this, will it interfer with filter maturation, or should I just wait until KH increases later whilst maintaining the water changes?
Thanks
 

Themuleous

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Lots of people run tanks with undetectable levels of KH and they don't have any problems at all, with anything, fish, plants, filters, etc. So basically its nothing to worry about. Trying to raise the KH is going to be a loosing battle at least for the start, AS sucks it out pretty quick by all accounts. It'll adjust back to normal as part of your normal water changes given time.

Sam
 

willgaze

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Thanks,
as far as co2 addition is concerned do I just need to guess how much too add (as dropchecker always in yellow) based on lighting, plant growth etc? I have 3 x 28W lights over a 100L cube tank, 50 cm high) and I'm running one for 7 hours and then all f3 or 2-3 hours in the middle. Co2 delivery is quite high, several drops a second and gases into a Koralia pump which distributes it around the tank.
Cheers
 
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