High Calc?

PeterEde · Aug 19, 2022

I bought a Hanna Calc checker today and after using the Redsea test since I started and I believe I was doing it right.
My tests have been consistently 420ish since adding a doser.
Today my first Hanna checker test reports 492?
Is there such a discrepancy or did I do something wrong.

I'll not be dosing Calc for a few days.

But this leaves me wondering how accurate my ALK is also with the Redsea test. Which has been 8.5ish for the last month plus.

I'm thinking I'll have a very out of balance system

vetteguy53081 · Aug 19, 2022

PeterEde said:
I bought a Hanna Calc checker today and after using the Redsea test since I started and I believe I was doing it right.
My tests have been consistently 420ish since adding a doser.
Today my first Hanna checker test reports 492?
Is there such a discrepancy or did I do something wrong.

I'll not be dosing Calc for a few days.

But this leaves me wondering how accurate my ALK is also with the Redsea test. Which has been 8.5ish for the last month plus.

I'm thinking I'll have a very out of balance system

Retest and if still unsure which is right, take a water sample to a trusted LFS that does Not use API test kits and see what readings they come up with and to compare with yours

arking_mark · Aug 19, 2022

Hanna Calcium Checkers are at best +/- 6% assuming best practices are used. So about +/- 30ppm for most tanks.

The other test kit is probably no better than +/- 10% or roughly +/- 45ppm.

So your readings are within the error of those kits...and both are "right".

PeterEde · Aug 19, 2022

I did retest. I found I added about ant extra half of the tank sample.
Retest was down to 442

gbroadbridge · Aug 19, 2022

PeterEde said:
I did retest. I found I added about ant extra half of the tank sample.
Retest was down to 442

The Hanna Ca test is tricky to use.

You have to be very precise with measuring the sample, especially the 0.1ml tank water

I replaced the supplied micropippette with a lab quality calibrated version which helped a lot with measurement errors.

Having said that, the test tends to read high and these days I prefer the Red Sea test as it matches Triton ICP within about +-20ppm

vetteguy53081 · Aug 19, 2022

K

PeterEde said:
I did retest. I found I added about ant extra half of the tank sample.
Retest was down to 442

inda thought so
I find these kits accurate +/- 1

PeterEde · Aug 19, 2022

So if our target Calc is 420 we have next to no hope of testing near true.

I was tossing up getting another redsea. Seems I should have

gbroadbridge · Aug 19, 2022

PeterEde said:
So if our target Calc is 420 we have next to no hope of testing near true.

I was tossing up getting another redsea. Seems I should have

Calcium is such a major component of seawater, that it's not really worth trying to target a number.

Just watch the trend so you can keep on top of it's usage.

If you're using most types of two or three part dosing, if you match alkalinity consumption you'll be replacing calcium pretty well and shouldn't have to test more than monthly. In most cases Alkalinity consumption and Calcium consumption pretty much balance out.

PeterEde · Aug 19, 2022

gbroadbridge said:
Calcium is such a major component of seawater, that it's not really worth trying to target a number.

Just watch the trend so you can keep on top of it's usage.

If you're using most types of two or three part dosing, if you match alkalinity consumption you'll be replacing calcium pretty well and shouldn't have to test more than monthly. In most cases Alkalinity consumption and Calcium consumption pretty much balance out.

I've been match Calc and alk since adding a doser. Just no faith in my levels now.

gbroadbridge · Aug 19, 2022

PeterEde said:
I've been match Calc and alk since adding a doser. Just no faith in my levels now.

It's really not that important

As long as you are over 350 and under 600 it'll be fine

Which is about how accurate most test kits are anyway.

Chasing numbers is no way to enjoy your tank.

I chased numbers for years.

arking_mark · Aug 19, 2022

vetteguy53081 said:
K

inda thought so
I find these kits accurate +/- 1

+/- 1ppm precision. +/- 6% accuracy. Per Hanna.

HudsonReefer2.0 · Aug 19, 2022

Also the Hanna kit is very sensitive and uses such a small sample via the pipette that if u push the plunger past its stop point the reading will b incorrect t flowing the instructions and procedure is important w this specific test

Randy Holmes-Farley · Aug 19, 2022

IMO, the Hanna calcium checker is a poor design, which is freakishly sensitive to calcium in the blank.

As noted above, both 420 and 490 ppm calcium are fine anyway.

PeterEde · Aug 19, 2022

HudsonReefer2.0 said:
Also the Hanna kit is very sensitive and uses such a small sample via the pipette that if u push the plunger past its stop point the reading will b incorrect t flowing the instructions and procedure is important w this specific test

That is what I did first test. Pressed to 2nd point.
I watched the Hanna use video YouTube to see my mistake

PeterEde · Aug 19, 2022

Randy Holmes-Farley said:
IMO, the Hanna calcium checker is a poor design, which is freakishly sensitive to calcium in the blank.

As noted above, both 420 and 490 ppm calcium are fine anyway.

Thanks Randy
I'm using your recipe for alk/Calc. Just trying to keep the balance the calculator gives.
Ie 420 Calc 8.5 alk.

Randy Holmes-Farley · Aug 20, 2022

PeterEde said:
Thanks Randy
I'm using your recipe for alk/Calc. Just trying to keep the balance the calculator gives.
Ie 420 Calc 8.5 alk.

Those numbers are certainly good targets, but don’t take the calculator balance as suggesting target levels.

It’s meaning is more esoteric, being NSW levels plus or minus a balanced amount of calcium and alk. At alk of 8.5 dKH, I doubt you’d see a difference between calcium at 420 ppm and 500 ppm, but the “balanced” alk levels are very different.