Partial Water Change Question

[simonero]

I need to do partial water changes in my 10gal tank to cycle it with my fish.
 
The dechlorinator I have does not have explicit instructions, because I got it from a friend who works with it in bulk and in painfully non-descript.  It's just a container of dechlorinator + what sounds like what LFS describes as "Stress Coat" added in.  He instructed me, for a full tank, to drop in a "dollop"...
 
How careful do I need to be about exact amounts now that I'm only changing 25% of the water?  How much should I use?  I can't just dilute a "regular dollop" in 10gal and use partial - I have a limited sized bucket.
 
Also, does it make a difference if I put in the tap water first and then immediately dechlorinate it, vs. dechlorinating it before-hand or taking the fish out for a few min?
 
Sorry if this is a dumb question, I just didn't want to leave something akin to chemistry up to chance and risk my fish's life.
 
 

 

[attibones]

Stress coat is a product sold by API. I use it and really like it. For dosing your whole tank, you would add 5 ml per ten gallons. I have a three gallon bucket which I use for my water changes. If you are doing twenty-five percent of your tank, you are removing about 2.5 gallons of water. You'll want to use 1.25 ml of dechlorinator, assuming you add exactly 2.5 gallons back into the water. 
 
If you want to add the tap water first, this is fine, but you'll need to dose the whole tank to be sure that each molecule of water is treated. If you add the dechlorinator to the tap water while it is still in its bucket, you'll just add the 1.25 ml. Don't add the dechlorinator to the tank before the tap water. It is alright to pour the dechlorinator into the bucket before the new tap water, though.
 
As far as removing the fish, I wouldn't do it. You'll just stress them out. They will be fine in lower water for a while, and the chlorine will not kill them in the few minutes it takes for the dechlorinator to get into the water (if you are adding the tap water first). 
 
Stress Coat is safe to overdose, but I'm not entirely sure if that is what you have. I would stick to exact amounts for the meantime. You are looking at .5 ml per gallon, or 2.5 ml per 5 gallons, or 5 ml per 10 gallons.
 
I hope I didn't confuse you... I'm not sure that I worded that in the best way.

 

[fluttermoth]

 Don't add the dechlorinator to the tank before the tap water.

Can I just ask; what's your reasoning for this?
 
Many people, myself included add enough dechlor for the whole tank before they start refilling. I've certainly never experienced any problems doing it that way 

 

[attibones]

I am always just cautious about adding the dechlorinator first because I am unsure if it will work with the new tap water. I would just be more comfortable adding the dechlorinator after the tap water because you can be sure that the chemicals will seek out and neutralize the chlorine in the tap. If you add the treatment first and then the tap water, I don't know if those same agents will still be active by the time the tap enters the tank. 
 
Some dechlorinators are harsher than others. I know Seachem Prime is safe to overdose, as well as Stress Coat, but I think some of the lower quality products are not good to overdose. 

 

[fluttermoth]

Oh, ok, I see
 
Dechlor stays active for a good few hours though (between 24 and 48, for Prime), and even the cheaper versions would be very difficult to overdose on; they're basically the same, chemically, as stronger dechlorinators; they're just more dilute.
 
If it works for you, then no worries; I'm just cautious the other way; I don't want to risk raw tap water getting to my filters or my fish's gills

 

[attibones]

If it works for you, then no worries; I'm just cautious the other way; I don't want to risk raw tap water getting to my filters or my fish's gills

 
That's why I dose the amount going into the tank (plus about five gallons worth extra because I'm bad at math). For my smaller tanks, I usually dose the whole thing just because it is hard to measure out 1.5 ml in a cap. I have a few syringes, but most of them have been used for dog medicine, or for ammonia, and I don't want to risk it.

 

[simonero]

Stress coat is a product sold by API. I use it and really like it. For dosing your whole tank, you would add 5 ml per ten gallons. I have a three gallon bucket which I use for my water changes. If you are doing twenty-five percent of your tank, you are removing about 2.5 gallons of water. You'll want to use 1.25 ml of dechlorinator, assuming you add exactly 2.5 gallons back into the water. 
 
If you want to add the tap water first, this is fine, but you'll need to dose the whole tank to be sure that each molecule of water is treated. If you add the dechlorinator to the tap water while it is still in its bucket, you'll just add the 1.25 ml. Don't add the dechlorinator to the tank before the tap water. It is alright to pour the dechlorinator into the bucket before the new tap water, though.
 
As far as removing the fish, I wouldn't do it. You'll just stress them out. They will be fine in lower water for a while, and the chlorine will not kill them in the few minutes it takes for the dechlorinator to get into the water (if you are adding the tap water first). 
 
Stress Coat is safe to overdose, but I'm not entirely sure if that is what you have. I would stick to exact amounts for the meantime. You are looking at .5 ml per gallon, or 2.5 ml per 5 gallons, or 5 ml per 10 gallons.
 
I hope I didn't confuse you... I'm not sure that I worded that in the best way.

 
Thank you!  That is very informative.  One thing though - are you talking about dosage if I was using Stress Coat or if I was using a regular Dechlorinator?  Or is it the same either way?
 
What I have is, according to my friend, definitely Dechlorinator.  If this is possible, I wouldn't be surprised if it's a mix of the two products.  I wish I could get more details, but I already know I'm going to get a vague answer and I've been bugging him about everything a lot already.  Either way, I think I should treat it as if it is just dechlorinator to be safe.  

 

[fluttermoth]

Stress coat is a dechlorinator.
 
I'm afraid without knowing exactly what you have, there's no way of telling what dosage you need; they vary so much. Seachem Prime needs only 0.25ml per 10l, for example, whereas a cheap one I bought from Tesco, as a tide over, needed 10mls per 10l
 
I really think you might have to try and pin your friend down on this. Although dechlorinator is pretty hard to overdose on, without knowing how concentrated it is, it's very hard to  tell you what amount to use.

 

[simonero]

Stress coat is a dechlorinator.
 
I'm afraid without knowing exactly what you have, there's no way of telling what dosage you need; they vary so much. Seachem Prime needs only 0.25ml per 10l, for example, whereas a cheap one I bought from Tesco, as a tide over, needed 10mls per 10l

 
I really think you might have to try and pin your friend down on this. Although dechlorinator is pretty hard to overdose on, without knowing how concentrated it is, it's very hard to  tell you what amount to use.

 
Intriguing.  Two LFS employees told me that they weren't the same and should still use dechlorinator, when initially I didn't realize what I had was definitely dechlorinator.  Ughh..
 
I'll do my best to get an answer out of him tonight, or at least a quality level, and report back (if you guys haven't already singled it out)!

 

[simonero]

Just to follow up if anyone is interested - turns out it was Stress Coat after all.  My friend is just really bad at describing things specifically, apparently.....  I put in the reduced amount (a little more than you said though, it was hard to pour that little) into bucket water then put it in.  24hrs later and he's fine.  Hopefully it will work out the same tomorrow!
 
Gracias!

 

[snazy]

Just get a dropper bottle or similar. I have a smaller bottle of API stress zyme that has that special cap and I although I no longer use API dechlorinator I remember the dosage was one drop per gallon. I always put two drops to be safe, in case I missed the bucket on the first round I still use the bottle but refill it with another dechlorinator that has nearly the same strenght. It's very handy for very small amounts of water/small tanks where even a syringe can't help.
 

Don't add the dechlorinator to the tank before the tap water.

 
I refill with a hose directly from the tap to the tanks and always add the dechlorinator before adding the water, even though it takes quite a long time for some of the bigger tanks I have. So I don't think there's an issue with it as I've done it since I bought a python which is 1.5 years ago. But for that you need to dose the amount required for the entire tank.
 
If you use the bucket method, then just dose the amount required for each bucket, stir for one second and add that water to the tank.