Amazonia distorts PH/KH->CO2 ratio? - Aquarium Design Group

krisw · 05-25-2005, 03:27 AM

Hello,

This past weekend, I finally got around to switching out the Onyx sand for ADA substrates with Amazonia/powersand in my 40G tank. Yesterday, I measured my PH and KH. Previously, with the Onyx sand, Previously, my PH was about 7.0-7.2, and my KH 3-4, thus 7-12ppm CO2. (Admittedly not optimum CO2 levels) Now, the PH is 6.4, and the KH is 3 degrees. That would mean that I have a CO2 level of 36ppm, according to Chuck Gadd's chart. This can't be possible tho. It's a 40G tank with only one DIY bottle of Yeast solution with a Hagen bubble ladder. None of the fish are showing ill signs. Infact, my apistos are displaying some of the best colors I've seen from them. Plus, I have decent water/surface circulation from a powerhead and the spraybar from the Eheim canister. I'll probably end up just doing nothing unless I see the fish starting to suffer, but I'm curious as to the explanation of this. Could it be that the Amazonia is actually invalidating the PH/KH->CO2 relationship?

**AaronT** · 06-08-2005, 08:10 AM

Jeff,

In another thread regarding Amazonia's effects on GH and KH you got an email response back from ADA saying that the effects only last about a month. Would that mean that the skewing of the KH/CO2 relationship would no longer be an issue after a while?

I know Amano goes by 'feel' and counts bubbles and uses CO2 indicators. I guess I'm asking if investing in a pH controller would be useless once I switch over in a month or so.

jsenske · 06-08-2005, 10:23 AM

IMHO, investing in a pH controller would not be necessary, unless you just want it for kicks or if you enjoy tinkering with such equipment.

I do not know enough about the all the KH, pH, etc. relationships. I have never delved into those areas much, and have not had any problems growing nice plants. I wish I could speak to this more, but it is admittedly not my strong-point. The key is to keep the water clean and provide consistent nutrition for the plants

And not to get off-topic, but:
I subscribe to the "simplify" school for the most part and when I start to get to technical, I stress myself out and it seems like things get worse in my tanks when I over-analyze them. But if you like technical/science- which many do- by all means study it with conviction. I am just trying to show that it can be done otherwise.

I say, layout your tank, plant as heavily as the layout in mind permits, go easy on nutrients and CO2 levels for the first few weeks, keep up with water changes (2 per week, 25-50% for first 3 weeks, 30% once per week after that), get your algae-eating animals (shrimp, Ocats, +nerite snails and SAEs if applicable) in the tank within the first 1-2 weeks, stay on top of emerging algae- very close observation for first 6 weeks when tank is most vulnerable, look for signs of deficiencies and increase nutrients gradually when they appear, introduce macros gradually and only if you really see a need for them (I went 5 years straight doing very nice tanks, algae-free tanks and I did not know even what a macro element was). And most importantly...enjoy. I'm not saying it's always easy, but rather that you can make it easier through common sense, diligence, and patience. Most tanks come around "on their own" when the basics are followed for 6 months or so. Prior tanks that I know had all kinds of issues the first few months almost always eventually came around after that time frame with me not doing anything more than staying consistent.
That's my philosophy. Certainly does not make the study of the intricacies irrelevant- that can certainly help, it just gives me personally a slight headache.

I can also see where this approach would only frustrate someone with a different philosophy or personality.

**AaronT** · 06-08-2005, 10:30 AM

Thanks Jeff,

That's what I wanted to hear. I'm of the same mind. My test kits basically sit there and collect dust. I usually gradually ramp up my CO2 until I notice the plants pearl just enough at the peak hours of the day.

I'm redoing a tank that is already established once my aquasoil comes in so I'm not too worried about unstable parameters seeing as how the filter is already well seeded and lack of plants is certainly not my concern thanks to Ghazanfar and his contagious collectoritis. I do plan on setting up the tank for a day and then doing a massive water change before reintroducing the fish.

dmartin72 · 06-08-2005, 07:32 PM

Jeff,

When you do water changes, do you use R/O water?

**IUnknown** · 06-09-2005, 06:24 AM

You can still use the controller, you just need to change the setpoint to get the right Co2 into the tank. You can do this by feel, like was mentioned earlier, just observing pearling. Or Tom recommended creating your own chart with the shift of the KH tanken into account.

Quote:

You can do a dirty little method to figure out your CO2 relatively close(pH is log scale though but this method is close enough in general)

Take a tap water sample, lt it sit 24 hours, measure pH/KH, should be about 3.7ppm CO2 or so.

Take a tank water sample, let it sit for 24 hours, take a pH/KH reading. Assume the CO2 content in both are equal.

Take the difference in the pH, say 0.4, add that from the tank reading.

So a pH of 6.4 is really 6.8 etc.

This is not perfect, but it's doable and relatively close.
You can transform the scale to log scale to get a closer approximation but the accuracy gained from all that is still low.

But since folks do large water changes, the humics are really regulated to the substrates and much less so to the water column after a few water changes.

I highly recommend for folks like you guys to do the add enough CO2 to get the plants all happy and then a little more, I hate controllers personally.

Test kits and other things cause more problems in some ways.
Simple is good. I'm still leary of suggesting this method though to new folks, I've seen dead fish tanks and if you kill the fish, I do not care what folks say, that's bad advice if there's a high risk of a new person doing that.

Many folks in Asia do that I see many post on that. I see that here in the USA also. But I suppose it's better than algae? hehe
Amano's done it too. I've been lucky, I killed some shrimps once, no fish to date yet.

Regards,
Tom Barr

jsenske · 06-09-2005, 09:54 AM

I use only Houston tap water- straight from the faucet for all water changes. It is run through a carbon filter to neutralize chlorine- but that's it.