We've had this Poolguard PGRM 2 In Ground Pool Alarm or about a month and have found it very easy to use with no false alarms. I've testing twice and it works great. The first test was the first night we had it and I simply "stomped" the water with my foot on the far side of the pool and within 10-15 seconds when the ripple reach the alarm, it activated. The 2nd "test" was accidental when a large windstorm blew a pool umbrella into the pool and bam, it activated. In both tests, the alarm activated properly inside the house and at the pool.
Conversely, we've never had a false alarm including during several large and windy thunderstorms.
We've used the alarm both with and without the solar cover on. It works great either way. Real peace of mind.
2 notes for owners on this Inground Swimming Pools:
1. Unless your pool deck surface is very uneven, the unit will sit nicely on the side of the pool without needing to drill a hole in the pool deck for the small metal brace. Unless your pool deck surface is really uneven, I wouldn't bother adding a hole, the little metal brace unscrews easily.
2. It can be hard to sit the alarm into the pool or remove it without it going off and as other reviewers have noted, the instructions aren't clear. The way to get it in and out is to press the button on the back to reset it, this deactivates it for about 5 seconds which should be time to slide it in or out. If it goes off while doing this, just hold the rest again and it will shut off in a 2nd or two.
By the way, if you are wondering how big this thing is since their description is so lacking in details, it's about a 4 inch by 5 inch retangular tube. The end that sits in the pool is about 11 inches long and the top is about 10 inches. The bottom of the tube in the water should be 2.5-5.5 inches in the water according to their directions with 4 inches being optimal.