Quote

“I'd rather regret the things that I have done than the things that I have not.”
― Lucille Ball

Thursday, August 7, 2014

Swimming Pool Re-construction


As a part of our landscaping project, we wanted to make a terrace around the swimming pool.

My suggestion was to add a small children pool as part of the project. It would not be too expensive, as I still had enough tiles for a small pool. Only concrete, steel and plumbing expenses were required.

I will give you some details of the requirements I had, the design, some problems to solve and finally a slide show with photo's that will show you a lot of detail.

The time frame for the reconstruction was from early January until mid May, 2014.


Requirements

  1. No changes to the construction of the existing main pool (MP)
  2. Three external lights on top of the terrace
  3. Shower
  4. Children pool (CP) should have two tile levels for safety:
    • for easy step in and ...
    • also CP fits for children less than 3 years old
  5. CP and MP should be able to operate independently, but also logically as one pool, water levels equal
  6. CP without skimmer, no auto-fill, no lights, but overflow drain pipe with MP which can be closed
  7. Laminars for CP (terrace fountains)
  8. Better water testing capability
  9. Automatic operation for plumbing, chemicals testing and diluting acid, pump and lights
  10. Change switch for MP pool lights from manual to automatic
  11. Fence around it, with 2 entrances (for children's safety and to prevent the dogs will swim at night)

The requirements 1-8 are matched now, 9-11 will be future projects.

Design

The plumbing diagram displayed below tells you how it works.

The basic principle is that we can run (= filtering) the two pools independently, similar as with a combination of a pool and spa. We even can have one pool with water and the other empty for e.g. maintenance.

To be able to do this you need two 3-way valves, although you can do it with four 2-way valves as well. As I want to be able to change the valves automatically and remotely (requirement 9), and knowing that the valve actuators are quite expensive, I choose the 3-way valves. The other 3-way valve is for choosing or (a) the normal inlet in the CP or (b) the laminars (fountains).

Note: I had some problems with the order of 3-way valves in the USA, as they seem not be available in the Philippines. See my blog here regarding this experience.

I plumbed the vacuum outlets of the 2 pools together with a Tee, in stead of using one 3-way or two 2-way valves to switch the vacuum pipe from the pump to the two pools. If the vacuum inlet of the pool that you don't vacuum is closed with a simple pvc screw cover, you don't need any valves.

Further to this I disengaged the second vacuum pipe of the MP, which we never used, so without changing the construction of the MP I had an additional pipe for other purposes, see below why.

There is also an overflow between the CP and MP. If the CP water level becomes higher than the MP water level (because of rain, many people in the pool or the inlet and outlet fluxes from/to the filter pump are not equal for whatever reason, the water will flow to the MP. When I designed/built the MP years ago, I included already this pipe in the MP, but it was never used until now.

If to the contrary the level in the CP is lower than the MP, the flow will be in the opposite direction. Note that water level control and correction is only in the MP (overflow-drain pipes and auto-filling).

We have now a better water flow (flux) balance between the outlets and inlets from a pump point of view. Originally I had three outlet pipes (1-1/2 inch pipes, but metric size, see below) from the pool to the pump (2 skimmers and 1 floor-drain set (vertex plumbing)) and only two return pipes (pool inlet) from the filter to the pool. So the maximum flux was limited by the 2 return outlet pipes.

In the reconstructed design we used 1 of the 2 vacuum outlets in the MP as a third return inlet, as we never use the second vacuum outlet. Check the design diagram. So one inlet pipe of the MP is combined with the only inlet pipe of the CP. The same goes for the floor-drains.

So if there is no water in the CP we still have a flux of 3 pipes in and out in the MP, or if I don't want to filter the CP for whatever reason. Vide versa if the MP is out of order or I don't want to filter it, I have 1 pipe flux in and out in the CP, which is enough for such a small pool.

3-way valves

The 3-way valves are Jandy Never Lube valves with a universal 180 degrees actuator from Pentair, but other manufacturers have them as well. See my blog on the problems I had with ordering these valves.

This valve has a 3-way positioning capability. The central connection is the in- or outlet, the left and right connections are at a 90 degree angle. The following states are possible:

  1. central to left open (right closed)
  2. central to right open (left closed)
  3. central to left & right open (all open)

The problem I had envisioned already when I ordered the valves was that these valves have imperial sizes, while the water pipes we use in the Philippines have metric sizes. So there would be no perfect fit.

To resolve this problem I surfed the Internet for several weeks to find a solution, but not very successfully.  Although I found a solution, it doesn't mean that you can apply it. What I found was an imperial to metric adapter, but when I put a request for clarification on the website of the company regarding international delivery, I got no answer, even after some repeated requests.

Finally I decided to go for a simple local solution: turning the pipes on a lathe to the correct dimensions. I used a machine-shop in Dagupan (Metropolitan in barangay Caranglaan) to do the job.

Of course this introduces another problem. The standard pipes I used are schedule 40, good enough for the swimming pool pump pressure used, but by turning off material the pipe is reduced to probably a schedule 20.

I have taken the risk, because the reduced pipe material thickness is compensated by the thickness of the valve pipe material thickness in which it fits. Together they may have even a schedule 80 size pipe strength.

Water testing

The last one and a half year of operation, we had regularly problems with algae and swimming insects, so I wanted to have better water testing capabilities (requirement 8).

My supplier of swimming pool products has only a simple tester for pH value and chlorine. And having done some research on the Internet, I concluded that also other suppliers in the Philippines do not sell better test sets. So I decided to order a test set in the USA, together with the 3-way valves.

I choose the Taylor Complete FAS-DPD Pool Test Kit K-2006. The pH test method is similar to what I had already, but is much easier to read the color indicator. I am very happy with this test set.

Back-filling

When the project was completed (except for the 3-way valve plumbing, which was delayed because of the problems with customs, see here), we could start the back-filling project of the garden around the pool and our house.

Pictures

We have a collection of photo's available, shared via this link.




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