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

jjencek · 10/12/2019, 01:24 AM

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.

Vinny Kreyling · 10/12/2019, 08:16 AM

Fauna Marin has a Multi-Reference solution bottle.
It lists results for:Calcium,Magnesium,Potassium,Salinity,Strontium,Nitrate & PO4.

jjencek · 10/12/2019, 02:27 PM

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.

hkgar · 10/12/2019, 02:48 PM

Quote:

Originally Posted by jjencek

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.

bertoni · 10/12/2019, 10:13 PM

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.

jjencek · 10/13/2019, 12:23 AM

Quote:

Originally Posted by bertoni

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.

bertoni · 10/13/2019, 10:01 PM

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.

hkgar · 10/18/2019, 01:52 PM

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.

hkgar · 10/18/2019, 02:52 PM

Check PO4 and NO3
PO4: Hanna 736 .18, Reference .18
NO3 Salifert 10, Red Sea Pro 1, Reference 1mg/L

Big E · 10/19/2019, 04:03 AM

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?

hkgar · 10/19/2019, 07:47 AM

Quote:

Originally Posted by Big E

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

10/12/2019, 01:24 AM	#1
jjencek Registered Member Join Date: Dec 2016 Location: Prague, Czech Republic Posts: 366	Calibrating/verifying test kits - Kh, Ca, Mg, etc. 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.

10/12/2019, 08:16 AM	#2
Vinny Kreyling Registered Member Join Date: Nov 2002 Location: Miller Place, NY Posts: 7,206	Fauna Marin has a Multi-Reference solution bottle. It lists results for:Calcium,Magnesium,Potassium,Salinity,Strontium,Nitrate & PO4. __________________ 250 gallon mixed reef, 2 Reefbreeder's Photon V 2, Deepwater BLDC 12, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 6 Tunze pumps.

10/12/2019, 10:13 PM	#5
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	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. __________________ Jonathan Bertoni

10/13/2019, 10:01 PM	#7
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	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. __________________ Jonathan Bertoni

10/18/2019, 01:52 PM	#8
hkgar Registered Member Join Date: Oct 2002 Location: Dewitt MI Posts: 5,051	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. __________________ Gary 180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels

10/12/2019, 02:27 PM	#3
jjencek Registered Member Join Date: Dec 2016 Location: Prague, Czech Republic Posts: 366	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.

10/18/2019, 02:52 PM	#9
hkgar Registered Member Join Date: Oct 2002 Location: Dewitt MI Posts: 5,051	Check PO4 and NO3 PO4: Hanna 736 .18, Reference .18 NO3 Salifert 10, Red Sea Pro 1, Reference 1mg/L __________________ Gary 180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels

10/19/2019, 04:03 AM	#10
Big E Registered Member Join Date: Oct 2002 Location: South Euclid, OH Posts: 4,281	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? __________________ 80g Rimless Acropora System reefcentral.com/forums/showthread.php?t=2197142&page=31 Ed