Quote:
Originally Posted by
Flower http:///forum/thread/379968/anyone-here-have-a-flounder/100#post_3307145
I see only one TINY flaw in your method. A new person does not know how much to drain away. Once it is in the drain it's gone. I always advise to hang onto that last bucket of saltwater until you refill with the new. That way if you over did your change you still have enough water to fill the tank back up. An inch or water off the top of a large tank may not look like much, but it is like 10gs of water.
The question:
so do i keep the pump submerged when doing thing or can i take it out of the water and keep the suction hose in the tank?
The answer: You can do it either way; once the suction has begun you can continue it as long as the hose stays submerged. You can also just let the pump do the work and not concern yourself with the hose.
I agree, it's a good idea to hang on to some of it for someone new in case of accidently taking out too much. That's why I like the syphon method as apposed to using a power head beacause it's slower. But I keep a close eye on mine so I rarely have an issue like that.
I have to dissagree with your generalization about 1" being around 10G of water unless you have a 300G tank that is 30" tall.
For Wayners tank or a standard 75G which is basically the same dimensions of a 55g but a little wider is still 21" tall...1" of water taken out equals 3.95G. So for a 5 gallon water change he'll need to take out 1.1/4" worth of water.
For Wayner, it's good to remember that taking out actual gallons is different than figuring out actuall precentages for doing water changes. For instance, the standard 75G tank when I put it in the calculater says that it holds 79 actual gallons. But once you take into account that most of us don't fill our tanks all the way to the top and you figure in the amount of solid mass that takes up volume in our tanks...things like sand, rockwork, livestock and equipment..etc, then that number changes. So unless somebody has accurately measured the amount of actual gallons in their tank from the start than the best any of us can do is make an educated questimation as to what that mass is.
Lets say that once Wayner eventually adds some extra rockwork in there he gets to somewhere where the solid mass takes up 10% of his actuall volume in the tank and figure he fills his tank about an inch or so shy from the very top. We'll say he ends up with 70 actual gallons totall water volume. In order for him to do a 10% water change he'll need to take out 7 gallons which comes to approximately 2". Essentially 2" would be as close to a 10% water change as I can figure without accurately knowing how many actually gallons his system has.
Edit...Sorry, math was off a touch. Pulled out the calculater...to do a 5 gallon water change you're looking at 1 1/4", Wayner. The 10% guestimation is for when you get a little more rockwork in there but it should get you by for now. A gallon or two here or there isn't going to hurt you to bad when it comes to a simple water change on a FOWLR system for your tank.