accuracy of API calcium test kit...

[flipteg]

i've been using the Seachem test kit for calcium... yesterday, my father bought the API calcium test kit... comparing it to the Seachem, the readings on both of our tanks are off, but the percentage it was off was the same... the API result was too high but if that result is multiplied by 0.65, the result is the same as with the Seachem... i was wondering if this is consistent with everyone else's experience with this test kit... because even if the API is off, as long as it's consistent, i can use it as an easier to use alternative to the Seachem... plus it's only $7...

[carlso63]

I am not sure about the Seachem but keep in mind the API Ca reading is in 20 ppm intervals (300 /320 /360 /380/400ppm, etc.)...

IMO not a big deal -I myself use the API kit and have found it quite reliable and a better deal (cost wise) compared to a Salifert kit.

I have brought a sample of my tank water to 2 different LFS just for a comparison (one used Salifert kits and one used Elos) and found the readings I got using API kits were all "spot on" for pH /Alk / nH3 / nO2 / nO3 and pO4, compared to the 2 more expensive brands - except for the Ca which read 420 ppm API / 410 ppm Elos & Salifert; but, remember, the API goes in 20 ppm increments while the others have smaller increments...

[carlso63]

.

[dendro982]

I had both too - ended using API. My first API Ca kit gave results in 500+ ppm, what is not possible with the salt mix, I was used (IO). Half of year later was advised to buy another kit - this could be individual or batch defect of the hole size.
The second kit gives believable numbers.

Seachem kits are supposed to be able to measure organic Ca (they are making Ca gluconate), or something, like that - you can see details on their website.

[flipteg]

ok... i guess i'll pick up my own then... i haven't been doing my tests regularly like i'm supposed to... the major reason is because the Seachem calcium test kit is so cumbersome to use... i can use the API regularly and check it against the Seachem from time to time if i get readings that are out of the ordinary...

[impur]

API has always tested spot on when compared to Salifert IME. Cheaper, easier to get, easier when testing too.

[lactose]

My experience is that if the API kit is not old it is spot on with my salifert (I use the API much more often). However if you let the API get old it will shoot up to 500+. Not sure how old they can get and be reliable as I use them up quickly but I have one now as an example that is 9 months old that reads well over 500.

[impur]

Originally posted by lactose
My experience is that if the API kit is not old it is spot on with my salifert (I use the API much more often). However if you let the API get old it will shoot up to 500+. Not sure how old they can get and be reliable as I use them up quickly but I have one now as an example that is 9 months old that reads well over 500.

Now that you mention it, i have seen this as well. I try to get new ones every 6 months or so just in case.

[vessxpress1]

My experience is that the Seachem Ca kits have always read 80 to 100 ppm lower than any API or Salifert I've tried. It never fails. I bought a new Seachem kit. Still the same. They sent me a new bottle of reagent right away to try on my still new kit. Same result. Despite matching it's own test sample very closely.

I have many LPS and a couple SPS that look fine and have been growing. Add B-ionic and Kalk in the top off, DAILY. Test regurlarly.

When pH is 8.3, alk is 9+dKH, Mg 1350, and other calcium tests match each other around 430, should I trust the Seachem kit consistantly giving me 335 to 340 ppm max?? All tests being new? Purchased within the past year.

I am not the only one to have noticed this trend but Seachem stands by their Ca tests and says they have to read right if they match their known test sample.

[Mike O'Brien]

Elos actually reads in 25 ppm increments. Unless you buy solution D seperately, then you can get them in 5 ppm. You'd use C up untill the last drop and then switch to D.