New 18x36 pool in Upstate NY, plumbing questions

[puppycrack]

Hello-
I am new to this forum, and learning a TON of information about pools. I've never owned a pool or maintained before, and this site has been a terrific resource!


I am shopping pool builders in my area to build an 18x36 vinyl liner rectangle pool. Half will be shallow (3.5'), with the other half 6' deep end. I estimate this to be a ~21,000 gallon pool. I am trying to determine optimal plumbing and equipment options, as I am not too happy with what the PB's are recommending:


PB1: (2) aqua genies; no main drain. one 2" line for both skimmers, one 2" line for both returns (pvc flex buried, rigid at the pad). I have read the mixed reviews on aqua genies, and am thinking I'd rather go with a conventional main drain setup. Additionally, I cannot believe having a single 2" line for suction, and a single 2" line for return is sufficient.


PB2: Main drain system, 1 1/2" lines everywhere (pvc flex buried, rigid at the pad). One skimmer, 3 returns. It seems that 2" line is the norm these days, so maybe he hasn't caught up to the times.


That being said, I have requested from both a modification to their plans to use a traditional main drain system, with 2" lines.


What would the recommended configuration be for # skimmers, # returns, pump and filter? Here is what I'm thinking, but perhaps I am over engineering things for a pool this size. Distance from furthest return/skimmer to equipment pad will be either ~75' to ~110', depending on which location I choose to put the equipment pad.


3/4" stone backfill
2" PVC all around (suction, returns, and at the pad)
Standard double main drain, tee'd and going to pad in (1) 2" line
(2) skimmers on the long end, each 1/3 of the way in from the ends; each w/ dedicated lines
(4) returns. 2 on the short end on either side of the stairs, 2 on the long end opposite the skimmers. Each pair would be run with with a dedicated 2" line, for a total of (2) 2" return lines


So this leaves me with (3) 2" suction lines, and (2) 2" return lines.


For the pump, I am looking at a 1.5hp VS pump (Hayward Superpump, or a Pentair SuperFlo). The filter would be a 420+ sq ft. cartridge filter (again, Hayward or Pentair). There will be a 250k BTU NG heater, and future rooftop solar. No water features.


Does this seem like a good setup? Is the plumbing adequate? If the pump adequately sized? Is this complete overkill? I'm trying to get all my ducks in a row with the engineering, so I can get accurate quotes, prior to pulling the trigger. Thanks for any an all insights!


- pc

 

[atttech-2]

One skimmer is often times all you need. Two is helpful if your prevailing winds change directions from one season to another, ideally the skimmer(s) would be placed so that breezes can help the skimming action along with the returns of course. I would insist on 2" as well but splitting the returns 2 and 2 might be a bit over kill but then again PVC is cheap if that is what you want I don't think it should be a bank breaker. Main drains are not needed but I am one to talk I had one put in too. I would stick with the two major suppliers and buy all the same brand of equipment. Often times you get an extended warranty for having all the same brand.

You didn't mention it but don't let them talk you into a suction or pressure cleaner get a robot instead.

 

[Sseaman]

Our pool is the same size you are thinking, this is what we have that has worked well for us. 2 skimmers on long side getting most wind, 3 returns on opposite side, we also have returns in the steps. I ran each skimmer separate in case I ever need to isolate one or the other, the returns on the side or on 1 run and the returns on the steps are on a separate run. We also have a couple deck jets that each have their own run back to the pump. Probably overkill but it was what I wanted for troubleshooting in the future.

 

[puppycrack]

Thanks for the input. May I ask what pump and filter you are using? I'm concerned the 1.5HP pump the PB is spec'ing out (1.5HP, 2 THP) may be too much for a pool this size.

For anyone else caring to respond on this setup, I took some measurements, and the distance from the corner of the pool that all lines would run from pool to pump is ~65 feet. So the furthest line would be about 100 feet. Skimmers would be closer to the pad than returns.

Thanks!

 

[Nectarologist]

One skimmer is fine but 2 will get debris off quicker (if that would be an issue for you). I have 2 large oaks right by the pool and they drop so much stuff that floats on the water in the spring both skimmers are packed every day for 2 weeks. If I only had one I'd need to empty it twice a day.

I like the main drain because I can still run my pump if the water goes low at the skimmers (I don't have an auto fill). Just yesterday I woke up and I lost a "lot" of water overnight (86 degree pool & 48 degree night). I couldn't run the pump until I raised the water level if I didn't have a main. But I turned off the skimmers and ran off the main drain. I knew it was low the day before but I was expecting rain last night and all day today so I tried to get away w/o paying for the water

One other note, I used to work for a pool company and we had to fix a skimmer line that was the flex. There was only one skimmer (no main). I think strong the suction over the years finally collapsed the flex pipe. With no other way to move water the pool was turning green and we had to dig up the concrete decking and replace the flex line. If they had another skimmer and or main drain the suction would not be so strong on any 1 source and if 1 skimmer failed they still would have been able to circulate water. But prob never needed the repair in the first place.

Of note my plumber used the pb's pvc for the gas line so they ran one skimmer with flex. Flex is fine the above repair was really due to only one suction source (imo).

 

[jbb2388]

We have an 18x34 oasis shape vinyl liner. It has two floor drains, 1 skimmer both of which are plumbed with 2" flex and 3 returns plumbed w 1.5" flex. Seems to be working flawlessly at this point early on. See sig line and pic.

 

[puppycrack]

Thanks for the replies everyone. I've received a response from one of my PBs. They are planning on having three 2" suction lines; one from double main drain, 1 each from two skimmers. For the returns, they are planning on 4 1.5" return lines: 1 to an eyeball in stairs, 1 each to two eyeballs in the pool, and one servicing a swimout with two jets in it.

I know that you should have greater feet of head on the return than on the suction line, but I can't seem to find out how to calculate this in a parallel setup. When it was all 2" piping, I know 3 suction and 2 returns were ok, b/c pipe sizes were same. But with different size pipe on suction and return, I don't know. Can anyone tell me how this is calculated? Maybe Mark (who wrote the excellent Hydraulics 101 post) could chime in?

They are also spec'ing a Pentair SuperFlo VS pump, with a 1.5HP BHP. I might go with an IntelliFlo for future automation integration, but am concerned that the IntelliFlo is too large for a 21000 gallon pool with no water features.

Once again, thank you for all replies thus far, and thank you for this awesome forum.

- pc