28
Control
When the solenoid valve is switched to automatic (factory setting, see chapter 7.7), the
device controls the following:
Current actual value in the aquarium: pH 7.80. Auto pH has set pH 7.10 as set point. Symbol
for valve status shows “open” and “A” for automatic. CO is now added until a pH value of 7.00*
is attained. The device then closes the solenoid valve and the symbol for valve status shows
“shut” and “A” for automatic.
Now, due to consumption by plants and the compensation from the atmosphere, the CO
level decreases and the pH level slowly increases. After reaching pH 7.20* the solenoid valve
opens again and CO gets added again, till the pH level is dropped to 7.00*, and so on.
* for pre-selected hysteresis (switching point) of 0.1 (factory setting, see chapter 7.6)
pH value, CO and carbonate hardness (KH)
The three parameters, pH value, CO content and carbonate hardness are inseparably linked,
as they are interdependent.
How much CO is needed to maintain a particular pH value depends on the KH in the
aquarium. The higher the KH, the more CO is required. Once the KH and pH values are
known, the CO content can be calculated. The following table saves you making the
calculations and also shows the pH values which you can set as a set point without any risk to
your sh.
Never adjust pH set point values arbitrarily, without having determined the KH in your
aquarium, e.g. with a JBL KH test.
CO content depending on pH value and KH
CO
2
(mg/l)
KH
pH
2 4 6 8 10 12 14 16 18 20
7,8 1 2 3 4 5 6 7 9 9 10
7,6 2 3 5 6 8 9 11 12 14 15
7,4 2 5 7 10 12 14 17 19 21 24
7,3 3 6 9 12 15 18 21 24 27 30
7,2 4 8 11 15 19 23 27 30 34 38
7,1 5 10 14 19 24 29 33 38 43 48
7 6 12 18 24 30 36 42 48 54 60
6,9 8 15 23 30 38 45 53 60 68 76
6,8 10 19 29 38 48 57 67 76 86 95
6,7 12 24 36 48 60 72 84 96 108 120
6,6 15 30 45 60 75 90 105 121 136 151
6,4 24 48 72 96 119 143 167 191 215 239
6,2 38 76 114 151 189 227 265 303 341 379
Too little CO
CO correct
Too much CO
auto pH curve (see chapter 6.1)
To Next Page
Loading...
