Dosing wrong?

[JAKos]

So i'm starting to dose 2 part, i used the brs calculator tested alk at 6.9, wanted to get it up to 7.4 did the 39.2 ml dose it said. tested a few hours later and the test said it was 8.1? is this normal? perhaps dosing wrong? all the corals seem to be happy and not stressed. wondering what could cause this? is it normal when you just start out dosing? i also dosed enough according to the calculator to get it to 7.0 but only got it to 6.8 then it went up to 6.9 the following day? any help would be appreciated.

 

[Randy Holmes-Farley]

Might be the solution you dosed was not the one intended by that calculator (the carbonate version is twice the potency of the bicarbonate version of my DIY, which BRS sells).

Could also be you mis-estimated the actual water volume of your system, or maybe the testing was off.

 

[JAKos]

Yeah maybe, i took the tank size and sump size. guess it could maybe be testing? but i only got the test kit a few weeks ago.. guess maybe it could be a bad test kit.

 

[\m/reefsnmetal\m/]

I'm not the expert, but I don't think water calculation is as simple as tank/sump size. I think there is a formula that takes into account the amount of rock and other things that take up space inside the tanks. I've been dealing with similar concerns as I'm just getting into dosing as well.

 

[rmurken]

You’ll get to know how your tank responds to various interventions with different supplements. The calculators are grounded in rock solid scientific knowledge, but as Randy noted, there are a lot of real-world variables that mean your results may vary from the model.

As you routinize dosing and testing and maintenance, you’ll start to see how much of what additives has a given effect, and it will largely be consistent with the models.

 

[A sea K]

If you entered the advertised display tank and sump volume then you entered the incorrect volume into the calculator resulting in an overdose. My 80gal DT and 40gal sump are much closer to 75-80gal true water volume not 120gal.

 

[JAKos]

If you entered the advertised display tank and sump volume then you entered the incorrect volume into the calculator resulting in an overdose. My 80gal DT and 40gal sump are much closer to 75-80gal true water volume not 120gal.

then how much would i put in the calculator? since i put in the calculator 80 and 30 gallons making 110? if that's not how it's done then how is it?

 

[Randy Holmes-Farley]

then how much would i put in the calculator? since i put in the calculator 80 and 30 gallons making 110? if that's not how it's done then how is it?

You just have to try to estimate the actual amount of water in your system. It's not a perfect science, but the number is always smaller than the empty tank volume.

 

[JAKos]

Ah alright makes sense, guess now that i got my alk to where i wanted it to be i'll try and keep it stable there.

 

[A sea K]

then how much would i put in the calculator? since i put in the calculator 80 and 30 gallons making 110? if that's not how it's done then how is it?

The calculators are designed for "actual" water volume and as far as I know there is not a mass produced tank that holds as much water as what the tank claims, to farther skew things your 30 gal sump is likely less than (or close to) 1/2 full, and to go another step farther all your rock, sand and coral (if you have sand) also displace water so when you factor all these things in I would estimate you likely only have around 70-75 gallons of "ACTUAL" water volume between your display and sump tank.

Anyway, when it comes to using the calculator it is probably better to undershoot your tank volume as an underdose in supplements wont be harmful however an overdose certainly can.

 

[piranhaman00]

Back calculate your get your actual size in liters. This is assuming you added exactly 39.2mL and the reading was done accurately. Even if it’s off it will be close for next measurement. You also need to state which form of alk you used. @Randy Holmes-Farley alk solution is 2660dkh approx.

(tank volume)*(1.2dkh)=(2660dkh)*(0.0392L)

or

if 39.2mL raised 1.2dkh then

39.2/1.2=x/0.5

X=16.3mL for 0.5dkh, this will be more accurate because it assumes equal tank volume

 

[JAKos]

I used the soda ash to make the liquid soda ash for the alkalinity, what do you mean by "back calculate your get your actual size in liters"? do you mean instead of using gallons of calculator and put liters? and i'm pretty sure the 39.2 ml was done correctly.