Zoone

After an interesting discussion about co2 or not in Swedish municipal tap water in this thread (Swedish) http://www.zoopet.com/forum/showthread.php?t=92855 i tried to verify some part of it.

The text here is the same as in my post in the thread but translated into English.

Test 1

Test 1 was made to establish how the bubble rate is from a normally running aquarium.

The test was done in my 325 liter aquarium with 4x54W T5, pressurized CO2 and PMDD dosing, the light is on between 12:00 and 22:00.

I cut a leaf in half at 17:35 and measured the time between bubbles a couple of times;

22,9
22,8
25,6 -
15,1 -
24,8
17,6
21,5
17,0
25,0

I removed the highest and lowest value and calculated the mean value of the rest, 21,66 seconds (with all values 21,37).

Test 2

The test was done in my 325 liter aquarium without the lights on and in a room which was as dark as it could get, the CO2 was shut totally off at the beginning of the water change.

The water change was of the in-line type (in and out at the same time) and was running between 8:25 – 9:50, i was monitoring some measurements all the time and quit the change when they stopped changing, this was done to have only tap water in the aquarium (no CO2 or other accumulated nutritions).

I cut a leaf in half at 9:40 and measured the time between bubbles a couple of times;

29,8
29,6 -
30,2
30,1
30,9
41,4 -
33,8
31,9

I removed the highest and lowest value and calculated the mean value of the rest, 31,1 seconds (with all values 32,2).

Pictures of this could be found here http://zoone.se/?page_id=515&g2_itemId=5803 , the pictures is so so because of the focusing problem in the darkness but they clearly show all kinds of bubbles from the plants, the pictures are taken between 9:43 & 10:03,the pictures is naturally taken with flash, but the light from the flash is so short i cant imagine it affecting the photosynthesis.

According to me this clearly shows that there is bubbles from the plants at a water change without a running photosynthesis.

Edit 1: It’s somewhat embarrassing that out of the few algae affected leaf i have is clearly shown in some of the pictures.

Edit 2: I would also like to add that the bubbles is extremely hard to see by the eye in the darkness, the bubbles below the leafs is quite easy to see but the bubble bands is almost impossible to see.

Edit 3: My tap water has according to the municipal water company a pH of 8.5 (according to my measurement 8.3) and a KH of 2.5, the Swedish municipal water probably differs some from place to place but from what i have heard from Swedish forums my water represent it quite well.