salifert kh/alt test kit

[pinner_28]

:( :( hi all having a tough time with the instuctions they give if you use the table they give my kh is 12.2 and myalk 4.34 but if you take the numbers of reading x 16 for kh i get 3.84 and number x 5.71 for alk i get 1.37.Don't know if i'm way high or too low.anybody had this problem with one of there kits.

[Delphinus]

You can just use the table to keep things simpler.

If the table says you have 12.2 dKH and 4.34 meq/L (BTW both values are "alkalinity" it's just that the units are different .... to convert from meq/L to dKH multiply by 2.8 ), then your syringe reading must be "0.24".

So to do the multiply by 16 thing, you need to first take your value of 0.24 and subtract THAT from 1.

So (1 - 0.24) = 0.76 -> (0.76 * 16) = 12.16 dKH

or (1 - 0.24) = 0.76 -> (0.76 * 5.71) = 4.34 meq/L


... Which is quite a decent reading for Alk. They say NSW (natural sea water) has alk in the range of 2.6-2.7 meq/l (don't quote me on this exactly, I'm going by memory which is dodgy at best), and we like to have our Alk values "higher" than that of NSW in our tanks, for optimum calcification and etc., .... long story short: most people who track their alk, like to keep their alk at the 4.0 range. So not bad at all in your case. :)

[pinner_28]

Thanks Tony now it all make a little more sense.but should i try to get it down a little closer to the nsw level. :? .Or would i do more harm than good i have a few zenias that have stoped pulsing over the last few weeks and thought that might be the problem every thing else looks good.

[Delphinus]

No need to try to lower it, that will happen anyways as the reef starts to draw stuff out of the water. Coraline algae, any stoney corals, clams, snails, etc., all take calcium out of the water, and they need alkalinity to be able to do that. So generally say you start off with Calcium at 400ppm and alkalinity at 4.0 meq/l. As things start to grow, they will pull both the calcium and the alkalinity downwards. Once the alkalinity gets lower than NSW, things will not be able to pull calcium out of the water anymore (or not as easily as before), and the calcium will tend to come back up (assuming there is a source for this calcium). So the long term strategy is to keep both levels nice and high, and that's where things like buffers, two part additives, kalkwasser topup, or more complicated gizmos like kalk stirrers/reactors, calcium reactors tend to get used. This of course is a great oversimplification of things but as a model it kind of shows the relationship between the two values and it works for me. A high alkalinity tends to pull the Ca down; a high Ca level tends to pull the Alk down. A see-saw effect.

Tracking Ca and Alk in tanks with minimal Ca draw, such as fish-only tanks, or tanks primarily filled with softies, is probably less urgent than those tanks with high Ca draw such as those with SPS, or even LPS, clams, and so on. But even in the case where it's less important it's still nice to see things like coraline algae grow and so on. So even then it's still nice to know your Alk and Ca values are within good ranges.

cheers