Alkalinity and calcium problem

[Eggpaul]

OK, so I can't be sure the kit is working right, but that is what the kit says is 4.5 dKH.

Do you think something is wrong with the test kit? expiration is in 2019. The test regent is right on target too. when I tested 4.5 with salifert, I also tested 6 dkh with API though

 

[Randy Holmes-Farley Verified Community Expert]

It’s just super strange to have 4.5 dKH. Other than that, I have no reason to doubt the kit.

 

[Eggpaul]

It’s just super strange to have 4.5 dKH. Other than that, I have no reason to doubt the kit.

I agree. I'm confused. Api test kit shows it at 8 right now. Salifert at 5

 

[Eggpaul]

One thing, the API test kit is expired.

 

[Eggpaul]

It’s just super strange to have 4.5 dKH. Other than that, I have no reason to doubt the kit.

Also, when I did the last few water changes I had mixed and heated the water for days because I was busy. So each time there was a lot of precipitation in the container. Maybe that dropped the alkalinity down?

 

[DMG Reef]

This might not be your issue, but other reefers might benefit from it. I've used Salifert test kits for more than 3 yrs. When doing the alkalinity test, I always used 2 drops of KH-Ind. However, the kit I purchased about 9 months ago required 4 drops of KH-Ind. After doing such a simple test for years, I long ago stopped reading the directions. For some reason, thankfully, I did notice the difference within a week of using the kit. When I mentioned it to my LFS where I'd purchased the test kit, they looked at the kit under their counter that they had been using, and it also required the 4 drops. We looked at the calcium test kits, and those had changed as well, from 8 drops to 10 drops. There was nothing on the packaging to alert that the instructions had changed.

Lesson learned however. I scan over the instructions on new test kits to make sure nothing has changed.

 

[Jet915]

Here is the starting point. Black rubber at 1.0. End point was .67. I had added 100ml soda ash. It raised dkh from 4.5 to 5.0. Will keep raising like you said.

Question. Will I have to test water changes and if needed raise the dkh with soda ash also?

Might be a dumb question but dont you have to account for that air bubble between the black rubber?

 

[beaslbob]

Might be a dumb question but dont you have to account for that air bubble between the black rubber?

FWIW the only dumb question is the one not asked.

Dr Randy did a thread on this in the reef chemistry forum.

The air bubble stays the same. So you just measure by the amount the stopper moves. (well as long as your still pushing liquid out)

I didn't know that until dr Randy's thread.

my .02

 

[Jet915]

FWIW the only dumb question is the one not asked.

Dr Randy did a thread on this in the reef chemistry forum.

The air bubble stays the same. So you just measure by the amount the stopper moves. (well as long as your still pushing liquid out)

I didn't know that until dr Randy's thread.

my .02

So the air bubble always stays the same size with every draw? Hmmm, my magnesium might be lower then expected then.....

 

[Bpb]

So the air bubble always stays the same size with every draw? Hmmm, my magnesium might be lower then expected then.....

Yes you have to completely ignore absolute values on these titration tests. The only thing you measure is displacement at the end of the test. How much fluid you added to reach the end point. It takes new testers a bit to grasp this.

Unfortunately salifert does their chart based on absolute value last time I owner one, so if someone were to purge that bubble, and measure the absolute value, it makes for an inaccurate read. Because that syringe tip has fluid in it also. If you get rid of the bubble, you have MORE than 1 ml of fluid in the syringe now. And that is now how the reading is designed to work. Leave the bubble.

Ensure the plunger is fully depressed and the syringe tip is free of fluid (dry). If you test frequently and forget to manually dry it out, the syringe tip can retain water from cleaning.

Put tip fully submerged in titrant, pull the plunger back to the 1.0 mark.

Ignore the bubble. From here on out, ONLY measure the base of the plunger. Not the fluid level. Not the meniscus. Just the plunger.

If Red Sea, count displacement. If some other brand. And it specifies so, measure absolute value.

Ignore bubble and fluid level.

 

[Jet915]

Yes you have to completely ignore absolute values on these titration tests. The only thing you measure is displacement at the end of the test. How much fluid you added to reach the end point. It takes new testers a bit to grasp this.

Unfortunately salifert does their chart based on absolute value last time I owner one, so if someone were to purge that bubble, and measure the absolute value, it makes for an inaccurate read. Because that syringe tip has fluid in it also. If you get rid of the bubble, you have MORE than 1 ml of fluid in the syringe now. And that is now how the reading is designed to work. Leave the bubble.

Ensure the plunger is fully depressed and the syringe tip is free of fluid (dry). If you test frequently and forget to manually dry it out, the syringe tip can retain water from cleaning.

Put tip fully submerged in titrant, pull the plunger back to the 1.0 mark.

Ignore the bubble. From here on out, ONLY measure the base of the plunger. Not the fluid level. Not the meniscus. Just the plunger.

If Red Sea, count displacement. If some other brand. And it specifies so, measure absolute value.

Ignore bubble and fluid level.

Thanks, ill have to retest. I did my first test and got a really low Mg (like 950, reading from black plunger) so I thought I was doing it wrong. I use reef crystals so I didnt think my Mg could be that low, plus my calcium is 440. So I read off where the air bubble started and it gave me like 1250 (a huge difference!).

 

[Eggpaul]

I'm just dumbfounded by what's happening. Salifert is testing 5.7 dkh and API is at 9. The API expired November 2017, so maybe that is way off. I did the test regent with the salifert (6.7 dkh) and it was right on target! I'm thinking the Alk of my water changes dropped a lot because I left it in the container for about a week stirring and heated. So when I did water changes it slowly dropped my total tank alk down.

 

[beaslbob]

So the air bubble always stays the same size with every draw? Hmmm, my magnesium might be lower then expected then.....

what is important is the plunger goes down say 1lm. Bubble or no bubble or with different sized bubbles, 1ml of liquid is squirted out.

 

[Randy Holmes-Farley Verified Community Expert]

Also, when I did the last few water changes I had mixed and heated the water for days because I was busy. So each time there was a lot of precipitation in the container. Maybe that dropped the alkalinity down?

Yes, but not likely all the way to 4.5 dKH.