ok i have a general understanding of the three. my question is this. a friend of mine has tap water as follows; gh 2 degree, kh of 2 degree, and ph of 7.8 out of the tap. i dont know what the ph is out of the tap after is sits for 24 hour he will test that soon. why would his ph out of the tap be 7.8 with water that soft? also he has 7 tanks that range from 6.0 to 7.8 ph. he uses no chemicals to alter ph and has the same maintenance schedule on all of his tanks. any insight on this will be greatly appreciated as he and i are tring to gain a better understanding of these values. thanx
gh, kh and ph?
- Thread starter rus
- Start date
excellent article RTR (now i know what rtr stands for). so lets see if i got this right. his ph out of the tap may be high due to very low disolved co2 in the water. once in the tank co2 disolves into the water limiting the disolved metals abilty to buffer the water. and his tanks have different ph values due to different stocking levels(nitrification) and substrate. am i way off or do i need to read it again?
cut-n-paste from www.skepticalaquarist.com:
oft water with high pH can be an obscure headache for some, most commonly fishkeepers living in areas where municipal water originates as groundwater drawn from limestone aquifers. In such waters, when dissolved calcium and magnesium exceeds about150 ppm, municipal water boards may resort to a water-softening technique called the "lime-soda" method in order to precipitate some of the minerals, thus softening tapwater right at the plant. In the lime-soda treatment, first quicklime or its hydrated form is added to the water. Then caustic soda ash (sodium carbonate— Na2CO3) is added to the water, to precipitate out the calcium and magnesium, largely as carbonates and hydroxides, which get left behind in large settling tanks. The resulting water is quite soft, but has a high pH. Further softening with porous cation and anion exchangers would be possible, but that technology is likely to be too expensive for most water utilities
The quicklime (calcium oxide— CaO) used in this :lime-soda" technique is produced in a kiln, where heat drives the CO2 out of crushed coral, limestone or oystershell. The resulting caustic quicklime can be finely ground and slaked with water to form hydrated lime or calcium hydroxide (Ca(OH)2), a fine powdery alkali that is strong enough to neutralize powerful acids. The slaked lime is also an efficient absorber of carbon dioxide, so tapwater treated by "lime-soda" softening generally arrives at the household tap still depleted in CO2, which contributes to its high pH. Often fishkeepers with this artificially softened water that is combined with high pH find that the pH drops somewhat after 24 hours of aeration, curing it for twenty-four hours in a water butt. For the sake of pH stability in the aquarium, lime-soda softened water should always be separately cured before using it.
A do-it-yourself CO2 injection set-up in the water-curing bin could help restored the depleted CO2, dropping the pH to more ordinary levels before you add it to the aquarium. Just a hunch.
Alternately, this is a situation where I think peat filtration would work to drop the pH, all the more effectively because because the buffering is so low."
oft water with high pH can be an obscure headache for some, most commonly fishkeepers living in areas where municipal water originates as groundwater drawn from limestone aquifers. In such waters, when dissolved calcium and magnesium exceeds about150 ppm, municipal water boards may resort to a water-softening technique called the "lime-soda" method in order to precipitate some of the minerals, thus softening tapwater right at the plant. In the lime-soda treatment, first quicklime or its hydrated form is added to the water. Then caustic soda ash (sodium carbonate— Na2CO3) is added to the water, to precipitate out the calcium and magnesium, largely as carbonates and hydroxides, which get left behind in large settling tanks. The resulting water is quite soft, but has a high pH. Further softening with porous cation and anion exchangers would be possible, but that technology is likely to be too expensive for most water utilities
The quicklime (calcium oxide— CaO) used in this :lime-soda" technique is produced in a kiln, where heat drives the CO2 out of crushed coral, limestone or oystershell. The resulting caustic quicklime can be finely ground and slaked with water to form hydrated lime or calcium hydroxide (Ca(OH)2), a fine powdery alkali that is strong enough to neutralize powerful acids. The slaked lime is also an efficient absorber of carbon dioxide, so tapwater treated by "lime-soda" softening generally arrives at the household tap still depleted in CO2, which contributes to its high pH. Often fishkeepers with this artificially softened water that is combined with high pH find that the pH drops somewhat after 24 hours of aeration, curing it for twenty-four hours in a water butt. For the sake of pH stability in the aquarium, lime-soda softened water should always be separately cured before using it.
A do-it-yourself CO2 injection set-up in the water-curing bin could help restored the depleted CO2, dropping the pH to more ordinary levels before you add it to the aquarium. Just a hunch.
Alternately, this is a situation where I think peat filtration would work to drop the pH, all the more effectively because because the buffering is so low."
thank you wetmanNY. maybe a call to the local water treatmant facility is in order. so i wasnt far off then.