How do i train myself to get lower so I don't loft the ball.. I hear clunk every time.... and i will think i am getting lower but still hear a clunk.. i know this kills my ball everytime..

well for starters some people think that they need to lift up on the ball, hit up on the ball. This causes you to pop up at the line no matter how low or not low you are. Its an excess movement that makes it hard to repeat the delivery. It also lofts the ball too much when often you need to set it down lower.

So thinking stay low to the line might help.

And don't hit up on the ball, let the ball do the work, just roll it off your fingers. That's all it takes. This will also help improve your accuracy.

Another thing to try is to aim closer to you. If you aim at the arrows for your primary target, try aiming at the second set of dots.

A John Jowdy-ism is to think "heavy fingers" at the bottom of the swing. And then just roll the ball off your hand. Again more of the "don't hit up on the ball" theory.

Erin

Reverse pitch in the fingers will also help to stop you from hitting up on the ball....

I have a different question. Why do you use a 15 pound ball and a 12 pound ball?

I used to bowl with a 10lb ball. When i went to the pro-shop to get another ball, i asked for another 10lb ball but he told me to get a 12... so after a few months with the 12 the ball just kept getting lighter and lighter and it felt like it didn't drive through the pins. So back to the pro-shop to get another ball. I don't have the funds to keep upgrading in weight so I just bought something heavy (yeah dumb I know). If I could do it again I would of done a 14lb but to late now. I guess I will just lift a weight to get me stronger.

I don't know your weight or body frame but 12 lbs seems very light, too light. I could see using 12 lbs for spares possibly but the weight difference would throw me off I think. 15 lbs should be a perfect weight, exercising will help I've made it part of my game but just using the ball more will help you build into it.

Well, first of all, are you sure that the clunk is actually the result of loft? It could also be that you are releasing the ball too early, while it is still in the downswing. If you're not sure, have someone watch you, or put a towel on the lane.

Where should I place the towel? I've never heard of it and am interested.

Since, your focus and eyes should NOT be at your feet, a towel is used to find out where your ball is landing.
If you don't know where your ball is hitting the lane, lay a towel at the foul line. If you release the ball at your ankle, it should hit the towel every time. If you are dropping the ball, it will hit behind and drag the towel. Don't worry, it doesn't go very far.
If you want to practice getting the ball out in front of you, lay the towel out a little farther, and see if your ball clears it.

Try what Dennis said, place a towel length wise on the lane side of the foul line, and let us know if you are hitting the towel or going way over it.

Most of these problems are caused by bending at the waist instead of keeping your back fairly straight, all you want is about a 15 degree tilt of the back which to most people who try this feels like they are straight up and down, but try the towel suggestion with your normal approach, then try keeping more up right with your back and bending with your legs into the slide and see if it improves.