Med dosing

[Super_Blueberry]

When I comes to dosing a tank for various purposes, should I dose for the entire tank volume or just the close approximation of water volume? Reason I ask is with my 100g tank, between the substrate and sizeable driftwood, I'm a lot closer to 80g of actual water volume. That's a 20% difference and can add up quickly between over medication which probably isn't good, and let's face it, it's a good chunk of $$$ as well.

 

[Delapool]

To me I think they refer to the amount of tank water. That would be the most accurate.

I've never seen any warning labels though on this and have seen instructions on medicines stating how tank volume can be worked put using length, etc.

 

[jlk]

Good question here! Meds should be dosed based on actual water volume rather than what the a tank has the capacity to hold based on physical dimensions. Just make sure you are reasonably accurate in the actual volume as under-dosing meds (particularly antibiotics) can create more problems than you originally started with. I am pretty sure almost all meds state to dose 'x' med at a rate of 1 tsp per 10 gallons of water, not dose 'x' med per tank size (fictitious example here).

This calculator is meant for sw tanks (and theres much more complex ones than this!) but you can use the 'live sand' section to enter your inches of substrate and make an approximation for décor and enter this in the 'live rock' section or just enter '0' and it will give you a ballpark capacity for actual water volume versus a tank's capacity. Not perfect but it does offer a reasonable guess on water volume.

http://www.garf.org/calculators/tankvolumecalculator.asp

 

[Super_Blueberry]

That's what I thought, but then I started thinking along the lines of simplicity. It's easier to figure along the lines of the known tank volume, 10-20-55-220-etc., then to figure out an individual tank setup, so do the manufactures take a 10% variance when they package their meds....

I'm obviously overthinking the situation. K.I.S.S.

 

[Delapool]

I think jlk must be right, dosage is mainly by volume.

But the variance question is interesting when you read half/dose for catfish, etc for some meds. I'll throw it out and suggest +\- 20% is no cause for concern? Just thinking of human medicines. Which then makes me wonder if fish constantly absorb the medicine in a tank or say with antibiotics only take up so much.

I've dosed at half dose and lost fish and others at a desperation double dose and not lost them (although that can't be good for them of course).

 

[jlk]

Hmm....I would venture guess here and say that 'general' med manufacturers such as API or Tetra have some wiggle room (so to speak) in their dosing suggestions as most are quite under-dosed (antibiotics) and/or have a margin of error (ich meds). Medicated foods have limited wiggle room but really should be fed appropriately to ensure they are effective (dose via weight). Purchasing pure meds in bulk from a manufacturer or using non-standard aquatic meds (such as injectables) do not have much leeway for error and typically do not come with specific (if any) instructions.

Quite a bit of all this really is dependent on the type of med being used, fish being treated, tank conditions (some meds do not work in high ph or are made toxic, opposite for some others in acidic water), etc. Which makes all of this more complicated, unfortunately. In my opinion and going back to the original point, I do think general manufacturers incorporate some amount wiggle room for hobbyists or there would likely be a lot more casualties being discussed. Not sure if this helps?