Calibrating/verifying test kits - Kh, Ca, Mg, etc.

jjencek

New member
I have burned myself with a test kit that slowly crept down - K in particularly.

I have been nervous about test results since. I would love to check my test kits once in a while against a known value. Are there "simple" solutions I can premix to do so?

I have read that Kh can be checked by (1.1350 grams of baking soda in 1 gallon of distilled water=10dkh).

What about other tests?

Ca, Mg, Salinity, No3, Po4, Ph, etc.
 
Fauna Marin has a Multi-Reference solution bottle.
It lists results for:Calcium,Magnesium,Potassium,Salinity,Strontium,Nitrate & PO4.
 
Thank you. That is exactly what I was looking for. I was already planning to order some corals from Fauna Marin. I will throw it into the shopping cart and report back.

BTW the suggested RODI water with baking soda does not seem to work. I tried three test kits at "RODI water mix calibrated at 10dkh".

RS test kit "“ ALMOST USED UP (expired 10/19) 10.4
RS test kit "“ NEW (expired 08/19) 10.1
Salifert "“ NEW (expires 08/23) 11.0

then I did the same with my DT water ...

RS test kit "“ ALMOST USED UP (expired 10/19) 8.0
RS test kit "“ NEW (expired 08/19) 7.0
Salifert "“ NEW (expires 08/23) 8.0

Sea water vs. RODI water with baking soda, seems to work differently.
 
Thank you. That is exactly what I was looking for. I was already planning to order some corals from Fauna Marin. I will throw it into the shopping cart and report back.

BTW the suggested RODI water with baking soda does not seem to work. I tried three test kits at "RODI water mix calibrated at 10dkh".

RS test kit "“ ALMOST USED UP (expired 10/19) 10.4
RS test kit "“ NEW (expired 08/19) 10.1
Salifert "“ NEW (expires 08/23) 11.0

then I did the same with my DT water ...

RS test kit "“ ALMOST USED UP (expired 10/19) 8.0
RS test kit "“ NEW (expired 08/19) 7.0
Salifert "“ NEW (expires 08/23) 8.0

Sea water vs. RODI water with baking soda, seems to work differently.


Not really. It is the test kits because they are designed to be used with salt water and not fresh.
 
I'd expect some inaccuracy using saltwater kits to test freshwater samples because the end point is different. I think they should read a bit high, since the saltwater end point is lower.
 
I'd expect some inaccuracy using saltwater kits to test freshwater samples because the end point is different. I think they should read a bit high, since the saltwater end point is lower.

The problem was not as much as little "higher" or "lower", but that each test was measuring off different way depending on sea or RODI water. Assuming that the water was 10 dkH for RODI and 8 dkH for sea here are the differences:

1. test kit ... 0.4 off RODI and 0.0 off SEA
2. test kit ... 0.1 off RODI and 1.0 off SEA
3. test kit ... 1.0 off RODI and 0.0 off SEA

If you look, test 2 was accurate for RODI, but was way off on SEA. And test 3 was way off on RODI and then accurate on SEA.
 
I haven't had the best experiences with Red Sea test kits, but the newer designs are supposed to be better. The tests are all within 10% of each other, which might be about all we can expect of hobbyist alkalinity kits. I would have hoped for a bit better, but all likely are close enough on saltwater.
 
I just got the Fauna Marin Multi reference. Here are some results
Calcium: salifert 450, reference 422:
dKH; Hanna 7.1. Salifert 8.1, Reference 6.6
Mag: Saliferrt 1275, reference 1315.

I used the Fauna Marin as the test soultion. Teh reference is th value states the solution is.
 
Check PO4 and NO3
PO4: Hanna 736 .18, Reference .18
NO3 Salifert 10, Red Sea Pro 1, Reference 1mg/L
 
Hmm....on the No3....I've compared Salifert & Red Sea Pro many times and they were always within 1/10 or so from each other.

Did you divide by 10 on Salifert if looking through the side?
 
Hmm....on the No3....I've compared Salifert & Red Sea Pro many times and they were always within 1/10 or so from each other.

Did you divide by 10 on Salifert if looking through the side?

Looked top down
 
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