Volume or Illusion?

I am about to add a couple of coral that a friend is providing and will be using supplements. I started reading the dosage requirements as a lot of additives have and they provide an amount (usually capfulls) per quantity of gallons. If an aquarium is loaded with things such as rock what it the real volume to be treated? Example: a 100 gallon tank half filled with LR should the dosage be for 100 gallons, 50 gallons or some estimate in between -or- has the manufacture assumed you have stuff in the tank so dose it for 100 gallons?

The same question could be for water changes in percentage. Is the cup half full or half empty?

Not an emergency question but a bit curious here.

 

Personally I go by the size of the tank. Once you figure out how much your tank consumes it is a little easier to supplement.

 

Thanks for the reply. I guess for my 85 gal. I will use that figure until I have a method without emptying the entire tank to learn the real liquid volume.

 

I would not use or add a lot of this stuff it will casue problems and you would not be the first.. But if you feel the need then I'd suggest Kent's essential elements and dose at a 1/3 of what they suggest.. It as will all elements cause algae and excess nutrients issues .. They all want you to dump it in as they will sell more and then the associated problems they will sell a fix for that also.

 

Forget "additives." In long run will cause you nothing but problems. Just about all are nothing but marketing hype designed to separate you from $ more likely used much better elsewhere...

Do regular water changes and let salt mix take care of needed elements.

Only thing you may need is a Ca supplement if keeping sps...otherwise need nothing in general...

You will eventually discover amount and frequency of needed water changes by state of water params over time.

May need to do larger ones more frequently until tank matures...eventually will need regular smaller ones.

I do 15 gallons a week in my 125...which may even be more then needed. But keeps everything happy and healthy and params and water clarity pristine...

Cheap and very effective practice IMHO.

 

Good question. I've always read the label just as it reads. IMO they don't assume anything. For my 90G, for example, I have a few inches of sand and a couple of cubic feet of LR, I have a 20G long sump/'fuge, that's about 75% full. With the 90G tank and the 15G sump, minus the sand and LR, I dose the product for 95 or so gallons.

If you're feeling sporty with a calculator, and have a refractometer, you can do a water change and get an even more accurate figure. Say your tank salinity is 1.025, and you mix SW for a water change of 1.022 (just for this test, in reality you'd mix your water change at the same salinity as your tank water. .. ) If you do a 10G water change, you can figure out what the resultant salinity should be for 100G. Using a refractometer, figuring out the difference as a percentage should allow you to figure out pretty darn close what the entire system's capacity is.

Hope this helps!

 

Thanks for all the input. The only reason I am considering the additives is that is what my friend has been doing and the coral will be coming from his tank.

Being an engineer I will try out ReefSparky's idea, just for fun. As for the other input, I would much rather not add anything except clean water. I continue that and see how things turn out. The parameters have been spot on, even the Ca, 420ppm. The only thing low is the good iron, Chelated and I guess pretty simple to change but I might not fool around with that one for now.

 

I read my post above, and think it might benefit some to be a bit more specific.

So for clarity, here's what I meant. First, you're going to make an assumption what your entire system volume is. For my 90, with the 75% full refugium, 3 inches of sand and about 100 lbs of LR, I assume my system volume is a total of 95G.

Going from this assumption, say you add X gallons of mixed water at a certain salinity. Using a refractometer to confirm of course, use the refractometer to measure the tank water a few hours after the introduction--and you can compare what it IS, to what you calculated it should be. This way, if it's 8% lower than what you calcluated it should be, then you can deduce your actual volume is 8% more than what you guessed.

As time goes on, you can dial this in precisely--using the same math; do your next water change accordingly. It should be spot on. If it's not, calculate the difference again until a water change at X salinity yields the precise result you calculate.

 

I am going to try it two ways, yours and another to compare. I think using your reasoning that when topping off using un-mixed pure water (maybe 5 gal) should work the same. I will check with my refac in the tank water before and after and determine the dillution to the salinity. The next time I will use mixed, measured 5 gal and do the same testing. Mine is an 85 gal with about 2" of sand and 150 lb LR. Should be interesting and definitely a nice number to be aware of. Will let you know results, maybe tomorrow as we have company today.

 

Absolutely!! You should do it this way instead. It would be less work. Your way you'd only have to mix saltwater once. Great thinking!! Karma to ya.