Basic question about nutrient/chemistry/ ph etc calculators

[undbulsu]

Many of these calculators list tank size in gallons. I assume that the calculations are based upon the actual amount of water in the tank and not the listed tank size. For example, I am currently in the process of filling my 72 gallon bowfront with R/O water, 3 gallons at a time. It looks like it will only hold about 55 gallons of water due to displacement from driftwood, substate, plants, etc. I should use 55 gallons for the calculators. correct?

 

[rich311k]

That is wjhat do, when I figure out fertilization amounts.

 

[Jchillin]

Good question. I had read somewhere that some consideration is given to displacement for the calculators, especially Chuck Gadd's. Unfortunately, I cannot recall where I saw it.

 

[Purrbox]

Doing your calculations based on the actual amount of water in the tank will be much more accurate, however it's not 100% necessary. I don't bother as it's easier to use the unadjusted volume and at least with ferts there's no issue with overdosing some.