25 years ago I had to choose between stone dust and sand when laying a brick patio using standard sized bricks. The underlying ground here in Virginia is fairly high content clay, I can absolutely state that stone dust is the way to go.... here are a few pointers; 1. Use a rigid but moderately flexible edge guard to define the area. I used aluminum about 4 inches tall. Don's use something softer like plastic or nylon as it will flex and your bricks will start to migrate all over the place no matter whether you use sand or stone dust. 2 . Use 4 inches of stone dust, but apply 2 inches first...then compact it with a manual or mechanical tamper....then thoroughly soak with water and wait a couple of days before applying the 2nd layer of stone dust and tamping and watering again. (BTW, I really don't understand the comments about stone dust not draining well....you will see the water soak quickly through the stone dust.) 3. Make the area as level as possible using a screed (look it up :) 4. Install some water permeable landscaping membrane on a fairly well leveled area. This will promote drainage and stop weeds from infiltrating from below. I will also make it easier to slide the bricks into place. 5. Install the brick. Either full size bricks or the thinner pavers. I used full size bricks which are more stable. To ensure that the bricks are level with one another, place a piece of piece of wood (approx 3" x 8" by 3/4" ) across the surfaces of the brick you are working on and its adjoining bricks...then hammer it with a large mallet until they all the bricks are even. Give then some good wacks...full-sized bricks can take it so long as you use wood as a buffer. Be gentler with the thinner pavers. 6. Depending upon your personal preference, you can butt the bricks directly up against one another or place a think spacer between them. I use pieces of asphalt roofing shingles to maintain uniform spacing. I like the look and using spacers allowed me to adjust the alignment for bricks which may not be uniform size. 7. Regardless of which way you go on item 6, sweep stone dust into the joints between the bricks. Wet the area, let it dry and repeat again. The irregular shapes of the stone dust will lock the bricks into position much better than sand, which is more round. Sand will not get into some of the smaller joints between bricks. 28 years later I am still VERY happy with my results. Occasionally a nearby tree root will distort things a bit but that will happen with either sand or stone dust. I just remove a few bricks and cut out the root. The only periodic maintenance I need to do is sweep new stone dust in the spaces between the bricks one ever 4-5 years. Good luck.

A fiberglass shell MUST have at least a two foot and preferably a 3 foot concrete collar. This provides added weight and rigidity, especially if the pool needs to be emptied for service needs. Concrete crack formation can be minimized by using certain techniques that may add to the up front cost. Some masons cut these corners to come in on a job at a lower cost. Cut corners may include improper soil prep, fewer expansion joints, cheap mix, thin spots, and a litany of other potential variables. While it's true that even with the extra steps taken, concrete may still form a crack, it creates a surface that will last decades and will be unaffected by a salt cell's use. A swimming pool salt water chlorine generator won't create cracks or make them worse. Someone is swinging the FUD bat. FWIW, pavers are usually made of concrete, just in smaller pieces. Some regions actually pour a concrete bed first. Sea water is a different animal than water in a pool. It's a different salt and in a different concentration plus there are a lot of other factors that are different. What the ocean does to concrete and steel vs. what pool water does is comparing apple to oranges. Scott

We had a similar decision to make last winter and ultimately went with concrete. For us, the look of concrete goes better with the house and it's cleaner because there is no sand between pavers to track inside. That, and it was the cheapest option. Wet-laid flagstone and brick are much nicer but about 5x the cost. Depending on the gravel, there may only be minimal surface prep needed before being able to pour right on top since you're already 4" deep. Especially if you go with concrete, make sure you get someone who knows what they are doing and gives you details on exactly what will be done (rebar spacing, type of concrete mix, finish type, cut lines, etc). It's true that concrete cracks. After 1 harsh winter we have a few _hairline_ cracks (you really have to look to see them) but even so we're still very happy how the slab turned out.

If you are going over concrete that slopes toward the house, you won't solve a water problem by putting something on top of it at a different grade, the water will simply find its way between the two layers and then you'll have a different issue of the top layer falling apart in addition to the water still flowing to toward the house. Using the composite paver grids might be the solution for the top layer as it is designed to "float" but it won't direct the water differently. Have you checked at a place that sells pavers to get some advice? Look for some place that sells Belgard pavers or a similar brand (not a box store) or a Siteone landscape supply outlet and go there for some advice.