Cupramine dosing; something fishy going on

TeeJay87 · Mar 31, 2022

I have a 20g long QT. According to the cupramine instructions, 20 drops 2x (i.e. 40 drops total) for every 10.5 gallons is needed to reach the therapeutic 0.5mg/L concentration. So for my 20 gallon tank, 20g/10.5g * 40 drops = 76 drops needed to reach 0.5mg/L.

So my plan was:
start with 40% of the 76 drops,
12 hr wait, 20%
12 hr, 20%
12 hr, 20%.

I did the initial 30 drops yesterday afternoon (40% * 76). I then tested with the seachem copper test kit this morning.

To my surprise, it appeared I was very near the 0.5mg/L concentration, but it should have only been 0.2mg/L (40% * 0.5mg/L). The testing kit provides a reference liquid of 0.5mg/L copper. I tested that and it looked pretty close to the test result of the tank. The reference was a bit darker though so it appeared to my wife and I to be 0.6mg/L.

To dose the cupramine, I dropped it from the bottle. The bottle has a small hole and it was easy to drop 1 drop at a time at a ~45 degree angle. Maybe these drops came out too large? Maybe bad test kit? Thoughts?

Here’s a pic of the results. Top left is tank water test; top right is the 0.5mg/L reference test.

vetteguy53081 · Mar 31, 2022

TeeJay87 said:
I have a 20g long QT. According to the cupramine instructions, 20 drops 2x (i.e. 40 drops total) for every 10.5 gallons is needed to reach the therapeutic 0.5mg/L concentration. So for my 20 gallon tank, 20g/10.5g * 40 drops = 76 drops needed to reach 0.5mg/L.

So my plan was:
start with 40% of the 76 drops,
12 hr wait, 20%
12 hr, 20%
12 hr, 20%.

I did the initial 30 drops yesterday afternoon (40% * 76). I then tested with the seachem copper test kit this morning.

To my surprise, it appeared I was very near the 0.5mg/L concentration, but it should have only been 0.2mg/L (40% * 0.5mg/L). The testing kit provides a reference liquid of 0.5mg/L copper. I tested that and it looked pretty close to the test result of the tank. The reference was a bit darker though so it appeared to my wife and I to be 0.6mg/L.

To dose the cupramine, I dropped it from the bottle. The bottle has a small hole and it was easy to drop 1 drop at a time at a ~45 degree angle. Maybe these drops came out too large? Maybe bad test kit? Thoughts?

Here’s a pic of the results. Top left is tank water test; top right is the 0.5mg/L reference test.

Factor in useable gallons
With Rock and decor- some volume is reduced making it about 15 gallons available
Confirm level with a reliable copper kit other than api brand

LeftyReefer · Mar 31, 2022

I would recommend not using drops, and instead measure out ML's when dosing meds.
I've always found different bottles result in different drop sizes and how you hold the bottle effects it too. Especially when talking about lots and lots of drops, like 76 drops.... Much safer measuring out ML's.

cupramine is supposed to be dosed 1ML per 10.5 gallons on day 1 and then repeated on day 2.
So basically 2 ML on day 1 and then 2 more ML on day 2 should put you close to where you need to be. less room for error vs trying to squeeze 76 uniform drops into a tank.

TeeJay87 · Mar 31, 2022

Appreciate the responses. I will use that advice to measure out MLs. I’ll find a dropper or something on Amazon with ML tick marks.

I don’t have too much in the tank, but very possible I’m a bit less than 20g.

Ultimately, it sounds like I should trust the test and measure drops in the future. It might just be me and that it was my first go with this test, but I find it a bit ridiculous to be trying to determine between these shades of blue in Seachem’s copper Test kit. I see why people recommend the Hanna checker.

MnFish1 · Mar 31, 2022

For example - a popular cycling product - recommends using 'drops' per gallon. When you do - it often results in a huge overdosage

Jay Hemdal · Mar 31, 2022

TeeJay87 said:
Appreciate the responses. I will use that advice to measure out MLs. I’ll find a dropper or something on Amazon with ML tick marks.

I don’t have too much in the tank, but very possible I’m a bit less than 20g.

Ultimately, it sounds like I should trust the test and measure drops in the future. It might just be me and that it was my first go with this test, but I find it a bit ridiculous to be trying to determine between these shades of blue in Seachem’s copper Test kit. I see why people recommend the Hanna checker.

Probably a combination of drop size and under calculating the tank size, and difficulty in reading copper tests. Your tank probably holds around 16 gallons of water. LxWxH / 231 = gallons. Take the measurements on the inside of the glass, and subtract a bit for the PVC pipe.....

Jay

Faffer · Apr 10, 2022

I set up a quarantine tank today and measured out 10 litres of tank water and 5 drops of cupramine (instructions say 20 drops for 40 litres).

I tested using the Salifert kit and it showed 0.5mg/l.

In this case, I'd be inclined to skip the 48 hour dose as per the instructions and just measure copper levels every day and dose or water change accordingly.

MnFish1 · Apr 11, 2022

I would say - there could be an error in any one of your measurements - the volume, the drop size or the copper test. Before doing anything - I would get another copper test from your LFS to verify whatever measurements you're doing - and suggest you get a third test to see which is the correct one. Not a big fan of the salifert test kits in general.

Gigajoulz · Jun 25, 2022

LeftyReefer said:
I would recommend not using drops, and instead measure out ML's when dosing meds.
I've always found different bottles result in different drop sizes and how you hold the bottle effects it too. Especially when talking about lots and lots of drops, like 76 drops.... Much safer measuring out ML's.

cupramine is supposed to be dosed 1ML per 10.5 gallons on day 1 and then repeated on day 2.
So basically 2 ML on day 1 and then 2 more ML on day 2 should put you close to where you need to be. less room for error vs trying to squeeze 76 uniform drops into a tank.

Why do you recommend dosing Cupramine twice was much was what the bottle suggests? The bottle says 1 mL per 10.5 gal on the first day, then wait 48 hours and do it again - that's 2 mL not 4 mL. I'm just curious if I should be doubling the dose for some reason; I currently have an outbreak of Ich and just setup a QT using some API Super Ich Cure just because that's what I got my hands on first before I could make a long trek to my LFS.

LeftyReefer · Jun 25, 2022

Gigajoulz said:
Why do you recommend dosing it twice was much was what the bottle suggests? The bottle says 1 mL per 10.5 gal on the first day, then wait 48 hours and do it again - that's 2 mL not 4 mL. I'm just curious if I should be doubling the dose for some reason; I currently have an outbreak of Ich and just setup a QT using some API Super Ich Cure just because that's what I got my hands on first before I could make a long trek to my LFS.

The OP was using a 20G tank. that dosage was for a 20G tank.