Water changes?

[Noelemac]

I think my gears are slipping again with this question. If I have a 50 gallon tank but with adding my rocks and stuff it only holds 30 gallons of water, do I measure my water change from the 30 gallon guesstimate or the 50 gallons?

[SGypsyMermaid]

i just drain the tank down to the halfway mark, ignoring the rocks.

[Paul C.]

NO aquarium holds the number of gallons it claims. (in my experience) Measure in inches on the [b:823049ce9f]inside of the glass[/b:823049ce9f] the width, multiply that by the length, multiply that by the height and divide by 231. This will give you a better idea of what it really holds. I have a 100 gallon tank that actually only holds about 78 gallons and a 46 gallon that only holds 40.
Hope this helps. IMOPORTANT: Measurments must be done on the inside!

[SGypsyMermaid]

paul--no offense, but do you [i:7b6da587d4]really[/i:7b6da587d4] need to be that exact? :wink:

[Noelemac]

okay, gotcha. Thanks all.