ianiwane

I do 5bps into a 50 gallon tank kH is anywhere from 2-4 depends on the water out of the tap on any given day. Using an external reacter with no loss of co2.

Robert Hudson

One question, how can you even count five bubbles per second? Anything more than 1 bubble per second just looks like a steady stream to me. Its too fast too much for me to come close to counting accurately

hoppycalif

I find two bubbles per second pretty easy to count, but above that it is just an estimate. I consider mine to be 3+ bbs, but, for all I can tell, it could be 5. Since my bubbles go thru a powerhead pump I can hear each bubble hit the rotor, so that is pretty easy to count, or at least to compare to what it was yesterday.

Glouglou

Well, many scientific paper are out there on the net about low pH and the effect on life.

One that bother me is this one precising PH in relation with Nitrifying bacteria at Bio-Con Labs:

Description of who they are:

http://www.bioconlabs.com/nitribactfacts.html


Don’t look to good for me...

banderbe

Sounds like baloney to me Glouglou. I mean, at least in my experience.. my pH is easily in the mid to low 5's and I have no problem. Evolutionarily speaking it doesn't make sense either since there would have been ample opportunity for these bacteria to adapt to acidic solutions.

BryceM

First of all, in a planted tank, who cares about nitrifying bacteria? The plants take up so much that most of us have to add it back in.

I find this thread to be good food for thought. I'll throw in my random comments. First of all, it is essential to remember that one person's observations do not constitute scientific fact. I'm not aiming at anyone in particular by saying this and I don't want to sound argumentive, but it's important to remember. There are dozens of variables that aren't controlled for. I think Edward's approach of keeping fish in a KH of zero is interesting, and reveals that a lot of what we pass around as "fact" probably isn't.

Person X might like to keep 10 full-grown oscars in a 55 gallon tank while person Y has 2 endlers in a similar setup. One person's 4 watts per gallon is measured with old bulbs, no reflector, and a dirty cover while another uses brand-new AH-Supply stuff. One person's test kit says 7.4 while another's poorly calibrated probe says 6.2. Which is right? People in different areas have widely different tapwater. Fortunately, plants and fish are pretty adaptable and most everyone is able to find some approach that works. An understanding of the principles behind the physiology and chemistry is more important than trying to get parameter "X" to a certain value.

Regarding the KH/CO2/pH chart...... It works perfectly well as long as carbonic acid from CO2 is the only acid in the system and carbonates are the only buffers. Since this is never true, the chart can never be expected to be accurate. In almost every case it will overestimate the amount of CO2 present. Decomposition of fish food, fish waste, plant matter, driftwood, and other compounds will inevitably introduce organic acids that accumulate with time. Talking about ppm of CO2 is almost a useless exercize. I still think that dropping pH about 1.0 units from the degassed state is a pretty good way to get where you want to be. If you want to use a pH controller, thats perfectlyl fine, but you need to monitor the KH and degassed pH once in a while.

Regarding pearling...... This is a phenomenon that is observed when plants are producing O2 in water that is already O2 saturated. The best way to get pearling is a low fish load, tight fitting cover, intense lighting, perfect ferts, and a jungle of rapidly growing plants (stemmies). If you have a high fish load you might never see pearling. If you have only slowly metabolizing plants or a low plant density you might not overcome the rate of O2 loss to the atmosphere. Despite this, the plants can be perfectly healthy and growing quite well. If the plants aren't metabolizing due to a nutrient deficiency, no amount of CO2 will cause them to pearl.

I suspect that most of what gets reported around the internet as a "pH crash" is actually an ammonia spike. A low plant mass with an overstocked tank and a poorly functioning biofilter is a perfect setup. Nothing kills fish more quickly. A sudden increase in CO2 is also pretty impressive. I've seen this kill fish in a matter of minutes.

Being vertebrates, the biochemistry that takes place in a fish is pretty similar to our own. Hemoglobin is the carrier of oxygen in the blood stream and it looses its ability to carry oxygen when CO2 levels get too high. When humans experience a gradual increase in CO2 (such as in lung disease), blood pH goes down and our kidneys compensate by producing more bicarbonate and dumping more acid.The cellular mechanisms that compensate for high CO2 take hours or days to kick in and they're only effective to a certain point. Fish do the same thing, with much of their regulation taking place in their gills, as opposed to the kidney.

Cellular processes are also quite dependent on a stable pH inside the cell. Even a couple of tenths of a point can cause big problems. Fortunately the body has quite powerful mechanisms to regulate pH. I think Edward is right that high CO2 levels can be more toxic than low pH levels. For most people though, it's hard to understand the difference. This is probalby due to the fact that we're all accustomed to equating pH to CO2.

Still, there is a certain pH below which the fish can't adapt. This exact point differs between species. Fish that evolved in areas of low KH, like tetras and South American chiclids get along much better at lower pH levels than Rift Lake chiclids. It sounds perfectly reasonable to me that fish can survive in a pH of 3.7, although I'd recalibrate the probe once or twice to prove it. Just don't try to reproduce Edward's results without understanding how he got there. His water has no buffering capacity whatsoever. If you try to get to pH 3.7 by cranking up the CO2 you won't have to worry about the fish anymore.

Whew, what a novel....... sorry

hoppycalif

Yes, it was a novel, but a gripping page turner! I agree with everything you said, but reserve the right to change my mind tomorrow!

Skyfish

My tap Kh is 1 and I used to use bicarbonate to raise it to 4. Had a controller set at PH6.4. I knew what my Co2 was. This week I switched to ADA AS/PS and my Ph just dropped to 6.0 without adding Co2 and Kh was at 0. I am not using the controller anymore. I added bicarbonate and kH raised to 2.3 but at my 1st water change it was back to 0 and PH had dropped to 5.7. After a day back up again at 6.0. Now after reading this thread, I am not going to do add any buffer. Let it sit at 0. But my question is how do we know how much Co2 is present in the water column? With new/old plants in this new setup it will take a few weeks to stabalize. But I want to be rest assured that I have enough Co2 going in there. It's 75G, 3bps, dissolved through an inline Rex reactor. The Stellata and Umbrosum are showing signs of growth already.

Your findings are based on normal gravel with let's say peat base or not. But what about with ADA substrate where it brings everything down? Sorry if this is a dumb question.

hoppycalif

If you use the same reactor and the same bubble rate you should have very near the same amount of CO2 dissolved in the water. From there you can watch to see if BBA starts sprouting up - if it does you need more CO2. You can watch the fish to see if they seem distressed - if so you may be too high on CO2. And, you can watch the plants to see how well they grow, how much pearling they do, and from that decide if you need more CO2. There really isn't any accurate way to actually measure how much CO2 is in the water without spending a lot of money for much more sophisticated testing equipment. And, since our standard of 20-30 ppm CO2 is based on people's inaccurate measurements we can't even say what the optimum real CO2 concentration is.

Skyfish

Thanks hoppy. In a new setup with AS and PS you can't add fish for at least 4 weeks, so we'll have to rely on plant pearling/growth. Today after my 5th day, I have seen bubbles behind all my Java Fern and Bolbitus, and some tiny bubbles going upwards from some of the plants, so I think the CO2 is doing well. But I have not seen a drop in PH during the day due to CO2. KH remains less then 1.