Copper level in qt issue.. help please

[Liron Mishal]

Hi
3 tangs in qt, raised copper power to 1.8ppm following the dosing calculation that was posted here.
(I think it was posted by @HotRocks )
The qt has just a few pvc elbows and a hob filter with ceramic media.
I calculated it to the tee and dosed accordingly.
After reaching what should have been 1.8ppm, I tested with the api test kit.
I cant tell for sure, but looks like 0.5ppm?!
Cant get a hanna test kit around here, I think I can get a salifert,
But from my understanding it goes from 1 to 2 so resolution is poor.
The question is whether I should keep dosing or trust the calculation?

 

[Brew12]

Hi
3 tangs in qt, raised copper power to 1.8ppm following the dosing calculation that was posted here.
(I think it was posted by @HotRocks )
The qt has just a few pvc elbows and a hob filter with ceramic media.
I calculated it to the tee and dosed accordingly.
After reaching what should have been 1.8ppm, I tested with the api test kit.
I cant tell for sure, but looks like 0.5ppm?!
Cant get a hanna test kit around here, I think I can get a salifert,
But from my understanding it goes from 1 to 2 so resolution is poor.
The question is whether I should keep dosing or trust the calculation?

I would probably stick with the calculation as the test kits are very challenging.

Care to share how you did the math so it can be double checked?

 

[Big G]

I would probably stick with the calculation as the test kits are very challenging.

Care to share how you did the math so it can be double checked?

+1 ^^^ if you did the calculation to actually measure you tank and know the exact gallonage or volume measured it, that's the first step. As tanks are not actually the size they are sold for. A 20 gallon is not 20. It's usually less, but could be more.
And if you used an accurate syringe for dosing that's a good thing.
So if you've done both of the above, I'd go with the dosing as Copper Power has been right on the money in testing.
Those API tests are horrible.

 

[Liron Mishal]

Thanks
my calculations are:
26.7 gallons
39.32 ml to get to 2.5ppm
0.064 ppm/ml
27.52 ml to get to 1.75ppm

I dosed 29.2 m/l over 5 days. I'd love it if you could double check my calcs

 

[solitude127]

What kind of light are you in when looking at the color of the API test? I got 2 different colors when using inside light and indirect sunlight. Instructions say to use indirect sunlight

 

[Liron Mishal]

@solitude127 really?! I use LED ceiling light.. I will retest tomorrow morning and see if it changed

 

[Brew12]

Thanks
my calculations are:
26.7 gallons
39.32 ml to get to 2.5ppm
0.064 ppm/ml
27.52 ml to get to 1.75ppm

I dosed 29.2 m/l over 5 days. I'd love it if you could double check my calcs

Assuming water volume is correct, your numbers look good to me.

 

[Big G]

Thanks
my calculations are:
26.7 gallons
39.32 ml to get to 2.5ppm
0.064 ppm/ml
27.52 ml to get to 1.75ppm

I dosed 29.2 m/l over 5 days. I'd love it if you could double check my calcs

Looks like your dosage for 1.75ppm is right on the money. What kind of filter media are you running in the HOB?

 

[Liron Mishal]

@Big G
I measured the tank exactly, even subtracted the glass thickness

 

[Radman73]

For what it's worth, I took my 20gal QT and used a measured 1gal pitcher to fill it up 1gal at a time, let the surface movement settle, and marked it with a sharpie. Every gallon up to 17, which is where I stop filling it at. This way I can easily look in the QT and figure out what my volume is. The HOB filter has maybe a quart at most, so is largely immaterial to any calculations. Makes it very easy to dose medications in QT.

 

[Big G]

For what it's worth, I took my 20gal QT and used a measured 1gal pitcher to fill it up 1gal at a time, let the surface movement settle, and marked it with a sharpie. Every gallon up to 17, which is where I stop filling it at. This way I can easily look in the QT and figure out what my volume is. The HOB filter has maybe a quart at most, so is largely immaterial to any calculations. Makes it very easy to dose medications in QT.

+1 ^^^ did the same to mine. Helps my old head when busy and especially if the treatment is urgent to have the tank permanently marked.

 

[Brew12]

My experience is that people tend to over-estimate their water volumes in QT systems which would make copper more concentrated, not less.

 

[HotRocks]

Assuming water volume is correct, your numbers look good to me.

Agree. Math looks good to me.

 

[Liron Mishal]

Thanks guys.
Fish were in the qt for 2 weeks before starting the copper treatment
Ends next Thursday (yippee! ). I would hate to start the copper countdown again.