I have a feeling most kits are pretty fair. Its basic chemisty. labs have been using these reagents for a couple hundred years. One problem reefers not familiar with good lab chemistry practices have is contamination of their test kit reagent bottles. Like if you have a couple of dropper bottlles and they have the same type, color cap, dont cross pollenate them by putting reagent A cap on the reagent B bottle. That will rapidly contaminate and neutralize your reagents. and you will get bad results. like mixing up epoxy part A and Part B caps. major NO NO!
that said, maintaining clean, uncontaminated reagents, will keep the kit reading true, but each kit has a different scale of sensitivity. The more sensitive, kits have more dilute reagents. we meter out the reagents by drops, so a drop of more concentrated reagent will react more of the other reagent and ion being tested, like Ca or Mg. and have a larger indicating range per drop like maybe 50 PPM or a whole DKH or PH. a more dilute sollution of the same reagents will give you a finer reading, like maybe 20 PPM per drop. Thats all the accuracy level means. general test kits have wider ranges per drop, and Professional ones are more dilute and give you narrower range indications. but you use more drops of it per test.
I use API test kits for things like Ca, PH and Alk DKH. they are wide range kits. but since there’s a wide tolerance range for these ions , its good enough for me. if my Ca is between 380-450, and DKH between 8-12, I’m happy. for Magnesium, i have used a Seachem test kit i bought a few years ago . does a lot of tests, like 150. and accurate within 30-50 ppm. Seems pretty good to me.
So I’m happy with fitting into the broad ranges, and not so concerned about testing to the last PPM.
But, you can choose test kits based on their level of resolution if you want to be more Persnickedy!
[quote=“fishguy9, post:80, topic:2865”]
there are VERY few reef tanks that are burning more calcium than what is replenished by routine water changes.[/quote]
Really depends on what you consider low. Low enough to kill fish, yeah maybe it nevers get that low. Low enough it isn’t healthy for SPS, and LPS, very easily done. If you use a high calcium, “reef” salt that is actually high in calcium this slows a bit, but still will result in lower calcium. Unless something has changed IO Reef Crystals has a calcium level of 380ppm! I believe tropic marine pro is somewhere around 425-430ppm.
Let me give a really simple example involving a tank that has low calcium absorption, but you still do MASSIVE water changes to try to maintain calcium.(massive = 50% which is greater then is healthy for the tank to do so, but further illistrates the point when you realize this much Ca is not being added during a typically water change) The goal for Ca is 425ppm. At levels below 400ppm growth of stony corals significantly lowers and with low levels of Ca, Mg, and Alk unsightly algae begin to grow.(so if you don’t really care how healthy your corals are just that they stay alive just consider that the unsightly algae have an easier time growing when your levels are off as well.) If you start off with cheap salt or a none reef salt your even more screwed.
Day 1 of record keeping
Ca 420ppm 50% water change done with Tropic Marine Pro resulting in 422.5ppm Ca
i/2 = 422.5ppm[/i]
Day 14
Ca 400ppm, 50% water change done with TMP resulting in 412.5ppm Ca
Day 21
Ca 395ppm, 50% change with TMP resulting in 410ppm Ca
Day 35
Ca 380ppm, 50% change with TMP resulting in 402.5ppm Ca
Day 49
Ca 365ppm, 50% change with TMP resulting in 395ppm Ca
You can see the trend in time even if you are doing massive water changes is headed down hill. If you aren’t paying $80+ a bucket for salt the numbers could be much worse. Most of us want to maintain our tanks for more then a couple of months and with in a couple of months things can get pretty low.
Perhaps people with thriving reef tanks that never dose their tanks attribute the eventual crash to some mystery old tank syndrome. Healthy tanks, wither they are FOWLR of full blown SPS, will grow coralline algae which uses calcium carbonate. If you don’t keep a healthy tank and don’t grow coral or coralline maybe things won’t happen as quickly, but the level will still drop in time as there are countless critters that absorb it.
The other side of this is Mg, which is REALLY low in most brands of salt(because it is more expensive and novice hobbyist don’t really care about it which doesn’t make any sense) Most of the animals in a reef use Mg to some extent. If it is low then it is impossible to maintain high levels of calcium.
Calcium ions are easy to add. but what really slows down corals extracting of Caclium from sea water is low PH. when the PH falls below 7.9 corals have a real hard time extracting calcium from the water. ergo the problem of ocean acidification by absorbing CO2 from the air. calcium is still about 420 ppm in the ocean. but lower is acceptable too if the PH stays above 8. the ocean has an average alk of 7 DKH. we keep our tanks higher than that for a buffer of PH swings. reefers who run calcium reactors often have a low PH number. due to the excess CO2 going back into the tank. . but it still works. plenty of Ca and carbonate ions .
http://www.reefkeeping.com/issues/2004-05/rhf/index.php
I dont know,. I have to try a calcium reactor someday. for now, i just add scoops of CaCl and buffer. .
like i always say. stay in the ranges.
Jon-
A good example, kind of like the build up of toxins in a tank.
Some real numbers here from one of my old log books. I did bi weekly water changes and testing on our 90 that we had in DE when I was getting rid of some cyano.
CA after 30% waterchange - 420.
CA 1/2 Week Later - 340.
Alk after the same waterchange - 9.4
Alk after 1/2 week - 7.2
And this is with only LPS and our Clam. Although I’m pretty sure the culprit was the 12" clam.
[quote=“icy1155, post:85, topic:2865”]
Although I’m pretty sure the culprit was the 12" clam.[/quote]
That’ll do it!!!
[quote=“icy1155, post:85, topic:2865”]
Although I’m pretty sure the culprit was the 12" clam.[/quote]
Ya think? ? ? ? ? ? 