It works best when able to be in full sun. Works best in short intervals as well. It still works on long runs but not as evident when placing hand over inlet to pool. It has a labeled IN and OUT but it doesn't matter which you use. Comes with fittings for Intex pool which made hookup a breeze.

Other posters saying they have leaks, I have found this is really due to the fact that it has many different connectors and you need to always make sure there is a piece of rubber between each connection or it will leak. The instructions could be better on how to handle this, but it does come with everything you need to insure you have no leaks. I got no leaks without using any of the included Teflon tape, but it did require me to figure some things out on my own.

Pro:
Ease of installation is the big bonus to this. Other solar setups will require a lot of construction and attachment, but this one only took me about 20 minutes without the purchase of anything else to put together.

Con:
The lack of surface area is the big drawback to this heater, especially for the price. So make your choice, do you want a much larger heater that will more effectively heat your pool but will require a huge amount of time and energy to install, or do you want simple and easy.

One other drawback is that there is a clear input and output on the panel which may make it difficult for you to set up properly. I had to invert mine but was able to cleverly divine a way to get it to work anyway.

I bought this solar panel for a above ground 15 ft round pool. This thing has been great! After 1 day it was keeping the pool at 82 and by day 4 the pool was up to near 90! I will say that if you want to keep that heat though, you must have a solar cover so that your heat doesn't dissipate to badly at night. The last two days, we have had very little sun and cooler temps in low 70's and the pool was still sitting between 80 and 82. Our pump is also less than 1hp so the water flows through it at a pretty decent rate and still warms up nicely as it goes through the coils.

Some things to note though

The hoses are not long at all, so if the panel needs to be placed somewhere away from the pump in order to get full sun, you will need to buy longer hoses.

We have an Intex sand filter and had to get creative at the local big box home improvement store to make adapters to accommodate longer hoses. No stars dinged for that though, because if you just used everything that came with it and you are able to put it right near the pump, you wouldn't have to do anything special. Mentioning this though because many people will be at the mercy of where the sun shines and you will most likely need longer hoses.

Did I mention the sun.. because you will need full sun for the better part of the day if you want to see those pool temps rise. If your panel is only getting sun for a couple hours, your going to have a bad time. Our panel gets a full 8 hours of sun where it sits and our pump runs 6 to 8 hours during that time. Partly sunny days keep it at 82 to 86, full sun days get's our pool near 90, and cloudy days it can drop to 80 if overcast conditions last a few days.

If you have a bigger pool, invest in more than one of these. One of these heats our 15 ft pool nicely, but I would think that if you have something bigger than a 18 ft or even a oval pool, 2 would be your best option. The longer the water stays in the coils, the more it will heat your pool.

I know I mentioned it up top but it is worth mentioning again, you need to have a solar cover. A solar cover is not just for helping heat your pool, it's best use is for keeping that hard earned solar heated warmth in at night. You can easily lose like 5 degrees of heat at night without a cover. If you have this panel and it never seems to get warm or stay warm and you don't have a good solar cover, that's not the panel's fault... that is your fault for letting all that wonderful heat escape into the night.

Overall, this panel delivers as long as you do your part to make sure it can do it's job.

I had to buy extra hoses because my hoses have a 1.5 inch connector on already. Existing hose from the pump to pool works to connect to the heater but I had to buy another hose from the heater to the pool.

The media could not be loaded. This will be our second year using these. We bought two and they have held up exceptionally well. They do exactly as advertised, per the manufacturer's statements.

We have a large pool and with two of these, they work moderately well. While it works in 75 degree outdoor temps, keeping the pool around 80°+, it's not going to make a huge difference when those temperatures get lower, so don't expect hot tub water. It's more likely to cause a 3 to 5 degree difference regardless of time of day or how long its been running. Rated it 5 stars because we knew going in, our pool was too large for these to make big changes, but they do work and they are very well made! You can even see dog feet prints on them and they never broke or cracked.

It is 1: 32pm, the pool cover has been off for just over 24 hours, outdoor temperature is 75°, and the pool temperature is sitting at 79°.