[Secret Agent Man]

it did seem funny it would increase it by 50%.

[FredZarguna]

The other thing, which I point out elsewhere, is that these planets are moving continuously towards this alignment. The gravitational forces for one planet can always be resolved into a vector that points along the same axis as the other planet, plus an additional vector which is tangent to that. The tangent vector gets smaller and smaller as the planets approach alignment, and at full alignment the radial component straight along one single direction towards the earth is at its maximum additivity.

What does this mean?

It means the effect, however large it is would already be seen. It doesn't just magically "turn on" like a light switch when the planets align and then instantly "turn off" when the planets are no longer aligned. It would build continuously toward a maximum, just like the length of the day does, and then fall off slowly once the planets are no longer aligned.

Whatever "magic float effect" there might be would already be well underway -- if it existed.

But it doesn't.