Quote:
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Originally Posted by droinablunt
...could anyone give me a tip to lower (my alkalinity)? It ius (currently) at 250 PPM
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Well, for starters:
- What test kits are you using?
- What is your daily pH range (8A(lights on), 12 noon, 4P, 8P(lights off)) ?
- What salinity are you maintaining?
- How do you currently supplement your alkalinity and calcium?
- Can you get a Mg test kit and find us some values?
All these values are interrelated. btw 250 PPM =~ 5 mEq or 14.8 dKH, a little high, but it will depend on what your calcium levels are and whick kit you're using to test for these values. Some kits are more reliable and accurate than others.
Hardness Units: ..................
Eq in PPM CaCO3:
1 mEq/l...................................... 50 ppm
ppm CaCO3................................. 1.0 ppm
1 grain CaCO3/US gal.................... 17.1 ppm
Clark (eng) 1grain/impGal............... 14.3 ppm
10ppm(france) CaCO3................... 10.0 ppm
1 dKH (Germany) 10ppmCaO........... 17.9 ppm
and
If you want to do the conversions:
(mEq/l) X 50 = ppm CaCO3
(mEq) X 2.8 = dKH
(dKH) divided by 2.8 = mEq/l
(dKH)X 1.25 = Clark ( English hardness units)
(Clark) X 14.3 = ppm
(Clark) X 0.8 = dKH
ppm X 0.07 = Clark
The definition of Carbonate hardness is that amount of alkalinity in seawater due to the Carbonate (
SCO2) content of the water column. This includes all the species of the carbonate/bicarbonate buffer system, and as
CARBONATE hardness does not include that alkalinity attributed to boron and it's differing species (boric acid/borate) BY DEFINITION. In practice, however, especially in the
marine aquarium hobby, this is often intended to mean total alkalinity, although this is not correct.
Boron levels in seawater are there mostly as boric acid, and at a pH of 8, are approximately 25% as Borate ion. The TRUE concentration of HCO3- and CO3-- are determined by measuring at least two parameters of the carbonate system (pH; the
total alkalinity, A
T; the total CO2,
SCO2; or the partial pressure of CO2, [pCO2]), and plugging these values into Frank Millero's formula for total alk. However, when we measure total alkalinity of the water column, we can titrate it with an acid, using an indicator dye to detect the point where all the carbonate is utilized to accept protons, as indicated by the color change of the indicator This is TOTAL ALKALINITY, including both borate and carbonate and miscellaneous other minor species, and is the method used by most home seawater test kits for alkalinity. Determination of Borate is possible using permanganate to oxidize all the organic borate to a meaurable inorganic form, then using a complex with mannitol and glycol in the presence of a strong acid, then titrating with a base (Salifert makes a borate test kit using a similar methodology). Seachem salts are unusually high in Boron, which, according to Leo Morin of Seachem, is because they (Seachem) feel that pH stability of the ASW made from this product is more important that the drawbacks of using high levels of Borate (open to debate... ). They now make a reef Seachem salt that supposedly corrects for this, but I am still not too happy with this product, and if you use Seachem ASW, you'll need to get their
alkalinity test kit that makes a bit more sense of the values with the high percentage boate/boric acid buffer presence. Personally, I see this product as fantastic for FO or FOWLR systems, but would suggest using IO or RC salt mixes instead for reef systems.
