Problem calculating sparge wate amount

I compensate for my false botton (2 1/2 gallons of water) in my mlT fill. I then calculate I need 5 gallons for spargung . Do I use this which will end up giving me an extra 2 1/2 gallons due to the mlt compensastion. Then just boil off the extra water,. I did try to comensate my spagre water to donw to 2 1.2 gallons * 5 - mlt false bottom), but that was almost impossible to do it slow. I tried to just dump the 2.5 from the hlt to mlt but would only last so long do to the teperature drop. I think I myabe got 20 mins of sparging this way, The other way I havent tried yet.

Any ideas?

Are you saying you're losing 2.5 gallons because of your false bottom? That seems insanely high. My system loss is a gallon across my entire system.

I have wide 15 gallon pots. Every .9 inches is a gallon. I like them too much to replace them so I think I might have to just boil off 2 1/2 gallons per batch I want to use the full sparge amount. Im not sure if the longer boil would be bad. Like darkening the wort or changing the flavor. Maybe boil the extra 2 1/2 off then add my adjuncts?

Why the hell is the FB lifted so high off the bottom? I assume it's because the bulkhead is below. Why not just lower it to under the bulkhead and use a pickup tube?

In any case, how much liquid is left after you fully drain it? That's deadspace and what you'd have to calculate into your losses, not what happens to be under the FB.

Right. As Bobby pointed out, anything left after you drain your mash as much as possible should be concidered system loss, and you'll just have to figure that into your numbers. If you work it into whatever brewing software you're using, you shouldn't have to boil off anything extra. It'll automatically add an extra 2.5 gallons of water to your brew and work the recipe around it.

If I was losing 2.5 gallons though, I'd be re-thinking my method of draining. Or, as Bobby mentioned...you could lower your false bottom and make sure the pickup tube is right at the bottom of your kettle. As long as you have good seals, it should create a siphon that will suck most of that wort out.

I do have a pick up tube and I can get almost every last drop out. Considering my FB is 2.5 gallons higher than the bottom I add an extra 2.5 gallons to the mash to make sure it's covered. Since Im doing that I would think I need to cut my sparge down by 2.5 gallons. So my question is, does the deduction in sparge water amount make this a bad thing. My eff% is usualy >75% which I would assume would improve if I lowered my FB and reduced the extra 2.5 gallons by somewhat. Dropping it down would be a ton of gridning since my FB has beefy SS legs.

You could put something under there that takes up space, like ziploc bags filled with water, or marbles, or something of that nature.

Hrm.... zip lock with marbles sounds like the way to go. Ill give it a shot with my next brew. Thanks!

You should probably use just marbles, that way they are more evenly distributed and you won't run into any channeling issues.

Marbles are used by vintners and mazers to fill up headspace in carboys due to losses when racking. This is the same concept.