I've done this type of build several times, it's my preferred way to build a pond. Main pond over flows into a smaller basin which pumps water back. My overflow would always be a stream or skimmer, but same concept. Lots of benefits to this type of design imo. Couple of keys...obviously the infinity edge has to be level...not, "I put the level on that and it looks level", I mean dead level. Really hard to do. If the mason really understands this he can do it. If he says "yes I understand what level means" he may not. If it was me I'd test him. He stood be able to explain why, in detail, why it has to be dead level. Everyone is happy when finished and perfect. Otherwise there's bad feelings and finger pointing. Better for everyone to be happy. A larger pump can some what fix a less than level edge. But the sheet of water will be jacked up. If the sheet isn't seen and you don't care about that then less than level can be OK, will still look like an infinity edge. Wide sheets take big pumps. You can do a drip edge type deal, still looks like an infinity edge but you don't have the sheet to worry about. Sheets are very difficult. Most infinity edges are viewed so you don't normally see the water coming over the edge, but I don't know the goal in this case. Another key is the catch basin has to be sized to the pump size. When the pump goes on it takes a while for water to fill the pipe and then fill the pond enough so water overflows the edge. During that time the pump is sucking water out of the basin, level goes down, pump goes dry, end of story if basin is too small. Even if the pond is filled to the top it still has to be filled more to over come surface tension. Could be talking about 100 gals of water. This can be fixed somewhat by sticking a hose in the pond and filling until it over flows and the basin is full and then turning on the pump. You may even have to keep the hose running. Downside is that when the pump is turned off the basin will overflow. So it's a good idea to install an overflow pipe in the basin and direct flow away from the pond and house. Muddy damp soil can lead to foundation problems. 1" of rain in a 100 sq ft pond will result in 10" water level increase in a 10 sq ft basin. Overflows are good, and very cheap. Last key is all evaporation will appear in the basin. Same deal as the rain only in reverse. IMO the basin should have an auto fill to keep it topped off. I like a regular horse trough automatic float value ($7-15), but fed by a sprinkler valve set to go on for a few minutes everyday. The float valves don't work forever and the sprinkler valve is your insurance of minimum flooding. Unfortunately the horse trough valves only last a couple of years, but are easy to replace. I'd buy a couple.

Yes, it is leaking from the front (pool side) to the trough side. The whole top is tile. It was not waterproofed on top... only the trough side was painted. JustaPB, what is the right way? I will post pics later today. Thanks.

just-a-pb...thanks for clarifying. Makes sense now, on a bigger pool, say greater than 60K gallons, a second filter makes sense to help with the dirt load and turnovers with low speed pumps. There's just not enough hours in the day to turnover larger pools with low flow rates to save energy. For our modest 40K pool, I only need to run the circulation pump at low speed for about 18 hours during the swim season to take care of turnovers and filtering...no need for a second filter and pump. Our negative edge pump only runs for a couple hours per day during the weekdays and off-season and 5-10 hours per day during the swim season and weekends when we tend to swim for longer periods. I should have clarified my post also regarding returning diry water to the pool...this only happens for as long as it takes to carry the water held in the basin to the main pool...after that it's carrying clean and chlorinated water to the pool. Using your logic...one could also argue for a chlorine generator on the negative edge pump in addition to a filter to prevent dirty, unsanitized water from being returned to the pool....just my perspective for what it's worth. For larger pools, I agree with a second filter and pump to save energy during low speed circulating and filtering. If you have a negative edge pool, it makes perfect sense to put that filter on the negative edge circuit. I would also say that for larger pools, the placement of a secondary chlorine generator may also be needed and placing it on the negative edge circuit would also make sense. For smaller pools with a negative edge, like mine, the need for a second filter is not necessary and placing one on the negative edge circuit is overkill in my opinion. I can see the argument either way though.

I just wanted to say THANK YOU, THANK YOU, THANK YOU for posting your pictures. I am not sure if you come back to this site anymore but your pool inspired our design and we are going to put that cool little pool into our design too. I spoke to our PB on Friday and he said it could be done!! YIPPPPEEEEE. I hope your pool makes it into one of those wonderful pool idea books! Katherine Here is our old pool design and below is my sketch of the new design. I put the elevated Baja shelf with spillover on the right and moved the fountain to the left by our existing patio! I can't wait to get started and post pix too! New design courtesy of your wonderful pool: