I, too, am currently using the "Lisa" method. However, I am researching different ATO's for use in my system. To date, I am not sold on any one method being the "best". Each seems to have failed at one time or another (including the Lisa method
).
The only foolproof method I have found is the restricted siphon system. No float switches, no electronics, simple Greek engineering. I will try to post a link when I find it. As long as you minimize splashing/waves near the siphon hole, and you have room to mount the rigid container in your stand or next to it, it should work 100% of the time without issue.
I can't seem to locate the post on it (it's on Reefcentral) because you can't search if you aren't a member. I will try to find it and post the link though.
EDIT --
Here's an email from someone who's system includes the restricted siphon:
"You need a rigid container. I recommend looking up "brewing supplies" in the yellow pages and ask for a "carboy" (that's what they call glass
bottles). It's the cheapest way to go. You need to get two rubber
stoppers. In one, you drill two holes and push a length of rigid air hose through them. One short... just to connect the air imput, and the other long enough to reach the bottom of the bottle. Both need to be air tight.
The other stopper just has one hole and is used to cork the end of the PVC.
The PVC need to be tall enough to reach the top of the bottle. If your PVC is short, the water will be sucked up into the air hose which will get
clogged. Look at the PVC in my picture... that's at the same hight as the
top of the bottle. I made the mistake in an earlier design of too short of a PVC "straw" and the water in the air tube caused problems.
Drill holes in the PVC straw where you want the water level to be maintained. It will work fine. Most of the time these will be just under water, but they occasionally will be exposed to let bubble up the straw.
Keep the siphon hose from the bottle to your sump under water. Don't let it drip into your sump, but rather empty into the sump below water level.
Actually, it doesn't matter where you let the water into your system...
anywhere would work fine. Just keep the open end of the siphon below the bottom of the bottle, and keep it submerged.
The drawbacks of this system are that the bottle needs to be above your sump level... some people hate that. Also, the bottle is sealed during use, making dosing calcium kind of hit or miss."
I will get some pics and post them later. HTH