Σε ό,τι αφορά στο KH και την αυξομοίωση του pH, ρίξε μια ματιά εδώ:
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
Λέει, συγκεκριμένα:
"Myth: A Low KH results in a larger pH swing when adding CO2.
Many people are under the mistaken impression that a low KH results in large pH swings when adding CO2, while raising the KH will result in smaller pH swings. This is not the case. The KH will move the start and end pH values, but the pH swing will be the same for a given level of CO2. You can see this in the chart below, or using the calculation:
Case 1: Assume a KH of 15 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 8.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 7.2, for a pH shift of .8.
Case 2: Assume a KH of just 1.5 degrees, and a starting CO2 level of 4.5ppm, which would result in a pH of 7.0. If we then add CO2, to increase the CO2 level to 28ppm, that would drop the pH down to 6.2, for a pH shift of .8, the exact same as in case 1.
One possible explanation for this myth is that many copies of this pH chart skip some of the higher pH values, for example, jumping from pH 7.4 to a pH of 8.0. If the reader didn't pay careful attention, they might mis-interpret the size of the pH swing. I specifically made sure to include all pH values, between 6 and 8, in steps of .2. This relationship will break down at extremely low KH levels (below 1 degree), when there isn't enough carbonate to completely buffer the acids present. In that case, the pH can drop quickly and dramatically. But if the KH is 1 degree or higher, then the size of the pH swing when injecting CO2 will be determined only by the amount of CO2 dissolved in the water."
Σε ό,τι αφορά στο ΚΗ=3 και pH=7, σύμφωνα με το πινακάκι αυτό εδώ:
http://www.aquatek.gr/vb/showthread.php?t=8483
αυτά αντιστοιχούν σε CO2=9ppm, που είναι μια φυσιολογική τιμή αν δεν έχεις επαρκή παροχή CO2 στο ενυδρείο.. Για την ακρίβεια, το CO2 αν δεν έχουμε παροχή στο ενυδρείο είναι έν γένει ακόμη χαμηλότερα, δλδ. το pH σου θα ήταν ακόμη πιο ψηλά.. Αλλά το pH κατεβαίνει, λόγω των οξέων που απελευθερώνει η τύρφη που χρησιμοποιείς..