southern homegrower
Well-Known Member
#1952
08-25-2009, 08:03 PM
greenthumb111
Stoner
Stoner
Join Date: Jun 2008
Location: SoCal
Posts: 701
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Quote:
Originally Posted by jberry
yea i forgot to mention the whole screwing up yer meter thing, sorry.
i knew it had something to do with ions.. lol
Ok let me take a crack at this pH issue.
In RO systems you have the feed water (input to the system) and the permeate (after filtering). When your water passes through the RO system you filter out ions (CO3 and HCO3) but not the CO2 which is a gas. This filtering will change the equilibrium of the water because 2 of the ions which control the reaction which produces the hydrogen ion (H+) were removed in the RO process. The H+ ion is what the pH meter is measuring The new equilibrium will always result in a lowering of permeate pHif there is CO2 gas present in the feed water. Usually, the pH drop is largest for waters with high amounts of alkalinity or HCO3. When there is very little CO2, HCO3, or CO3, there is very little pH drop observed in the permeate.
Therefore it is not true that reverse osmosis filters will always reduce the pH level of water to a noticeable amount. The pH difference after the RO depends on the composition of your input water source; depends on whether you have large amounts of gases such as CO2 in your local water supply.
If you are concerned with the pH of your RO water (If you see that your pH is indeed below 7 with a good amount), you can consider putting a pH increaser filter as a final stage of your reverse osmosis system and correct acid water problem easily.
You meters are working its just the water that has changed post RO. Hope this helps
__________________
https://www.rollitup.org/grow-journal...ml#post2419207
08-25-2009, 08:03 PM
greenthumb111
Stoner
Stoner
Join Date: Jun 2008
Location: SoCal
Posts: 701
permalink
Quote:
Originally Posted by jberry
yea i forgot to mention the whole screwing up yer meter thing, sorry.
i knew it had something to do with ions.. lol
Ok let me take a crack at this pH issue.
In RO systems you have the feed water (input to the system) and the permeate (after filtering). When your water passes through the RO system you filter out ions (CO3 and HCO3) but not the CO2 which is a gas. This filtering will change the equilibrium of the water because 2 of the ions which control the reaction which produces the hydrogen ion (H+) were removed in the RO process. The H+ ion is what the pH meter is measuring The new equilibrium will always result in a lowering of permeate pHif there is CO2 gas present in the feed water. Usually, the pH drop is largest for waters with high amounts of alkalinity or HCO3. When there is very little CO2, HCO3, or CO3, there is very little pH drop observed in the permeate.
Therefore it is not true that reverse osmosis filters will always reduce the pH level of water to a noticeable amount. The pH difference after the RO depends on the composition of your input water source; depends on whether you have large amounts of gases such as CO2 in your local water supply.
If you are concerned with the pH of your RO water (If you see that your pH is indeed below 7 with a good amount), you can consider putting a pH increaser filter as a final stage of your reverse osmosis system and correct acid water problem easily.
You meters are working its just the water that has changed post RO. Hope this helps
__________________
https://www.rollitup.org/grow-journal...ml#post2419207