Testing For Calcium & Free Chlorine Vs Total Chlorine

[rjordan390]

Can someone clearify what test kits are really testing. I have the Taylor FAS-DPD pool kit K-2006 pn order. When I test for calcium, am I testing for elementary calcium or calcium as calcium carbonate?

The basic chlorine test kit that I have now only tests for total chlorine. Will the Taylor kit give me both a total chlorine and free chlorine as a result?

[waterbear]

The K-2006 FAS-DPD test will test for FC and CC, To get total chlorine you add both together.

Calcium hardness is the measure of calcium ions (usually expressed as calcium carbonte but the acutal chemical test is only testing the calcium ions, Ca++, since this is what is reacting with the titrant.). The test is an EDTA titration at high pH to precipitate out magnesium so the EDTA will effectively only titrate the calcium ions in the sample and uses a calcon (or calcon like) indicator to determine when all the calcium ions have reacted with the EDTA.

Total hardness is the measure of both calcium and magensium ions and is not a useful measure for pool or spas It is what test strips test (they cannot test for calcium hardness).

Low calcium hardness is only a problem for plaster and fiberglass pools. It is not an issue fir vinyl liner pools.

high calcium hardness is an issue for all pools, as it can promote scaling or cloudy water (in conjucntion with high TA and high pH).

Total alkalinity is basically the same as carbonate hardness (or carbonate alkalinity) for our purposes and is a measure of the amount of bicarbonate ions in the water (there is little to no carbonate ions present in the water at normal pool pH). There are other ionic species that contribute to the total akalinity such as cynaurate alkalinity (only needs to be corrected for when the stabilizer is extremely high -- 100 ppm or greater) and borate alkalinity (if a borate product is used as an algaestat and pH regulator -- however the alkalinity from borate is usually ignored)

[rjordan390]

Thanks,

I assume CC stands for Combined Chlorine. I have to do a search to see exactly what that means.

[waterbear]

it means Combiined Chlorine (or the alternate term, combined chloramines)

other abbreviatons you might find useful:

FC is free chloirne

TC is total chlorine

TA or ALK is total alkalinity (or carbonate alkalinty or carbonate harness or Dkh)

CH is calcium hardness

TH is total hardness

CYA is cyanuric acid or stabilzer

pH is potential of hydroten

ppm means parts per million (bascially the same as milligrams/liter or mg/l

FC is chlorine in an active state that is availble for sanitizing

CC is chlorine that has combined with organics and is not longer an effective sanitizer

TC is both of the above added together