anyone had trouble with API test kits?

[new2saltwater]

Hi, im new to the saltwater hobby and have had a 100 gallon tank for about 5 months. everything is doing well in the tank but i have never been able to measure the calcium with my API test kit. it reads higher than 520ppm when tested. all other parameters seem good. using reef crystals salt. PH was stable at 8.2 but when tested today it is at 7.8. alkalinity is at 7dKH. I bought a magnesium test kit yesterday and it is at 1200ppm with my ELOS kit. Could my API test kit for calcium be inaccurate?

[cellowithgills]

Did you test the pH at the same time of day?

[new2saltwater]

Did you test the pH at the same time of day?

i did full test at about 11 this morning. i read that time of day can effect ph though so i tested ph again about an hour ago and still reading 7.8, which is a little strange because it has always been steady at 8.2.

[Smann]

My API Calcium kit always test 500+, dont use them any more

[new2saltwater]

My API Calcium kit always test 500+, dont use them any more

what kit do you use for calcium? i was thinking of buying one tomorrow and retesting already because i didnt want to try to correct a problem if it was a faulty kit.

[Smann]

You might try salifert, check the date on it though

[Smann]

Maybe take a sample to you LFS and see what test they use/sell and what it reads

[Algae]

If you have high CA and low Mg you are likely precipitating on heater and pump. You really need at least two or three kits (even from different companies) to verify your tests. When you are adding drops do not do them continuously. Drip a drop, let up on the pressure to allow for air to get in and drip again all while having the bottle completely upright. Good luck and post your results!

Here is a good read:

http://reefkeeping.com/issues/2006-06/rhf/index.php

[Electrokate]

I had a bad api alk kit in the last year. 2nd vote for Salifert. I switched all my kits to LaMotte and they are great for me but not so good for all users. Salifert is accurate enough and easier to use. Also watch out for super old kits, they do expire, and store them in a reasonable area. Not the garage where it gets super hot in summer and cold in winter.

I have seen some batches of salt with weird levels of calcium over the years so you might want to have a bit of your newly made up water checked too. That particular brand once had a batch of high calcium salt a couple years ago. Back in I think 04 had a bucket of another brand new to the market where the calcium was around 800. No kidding. LFS I worked at had a special on it and a lot of unhappy customers, myself included.
Kate

[new2saltwater]

ok, took a water sample to the lfs. tested calcium at 450. thats what i was afraid of, my api test kit is not working correctly. i tested my stored mixed saltwater and could not get a reading, just like when i test my display. going to try a salifert kit i think.

[new2saltwater]

finally got a salifert test kit for calcium. calcium measuring 420ppm. big difference from my api kit. been dosing for ph and magnesium, currently at 8.2ph, 9dkh, and 1250 magnesium. I have a candy cane coral that appears to be dying. could my low calcium be the cause? all other corals look good.

[kriz2fer]

I have trouble with the API KH test kit, every time its get down to the last bit it starts to read off. Calcium at 420 should be just fine though.

[markdadof2]

API kits are some of the most innacurate I have ever used. Elos and Salifert is what I use, but wanting to try the new Red Sea kits.