Help us start up our new pool! - tiled 6x12m swg

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My PB says he has made the calculations and that 3 hp is correct for this pool.

It would be interesting to try to make the calculations too, if for nothing else, to learn.

So, what are the parameters? We need to know the head. I dont know the PSI now, because the pump has not been run yet.

to get a 8h turnover, i need around 35-40 gpm flow, if i am thinking correctly. what other numbers do we need? i would assume we need to take distance from pool into account and height difference. The pump is 14 meter from the pool, and it is about 1,5 meter over the pool level. Pipe size is 2in.




The pool is now 50% full of water, i expect we start the pump on saturday. I tested the ph, its a little higher in the pool compared to the tap: around 8.
 
Your signature says 17,000 gallons, so 17,000 divided by 360 equals 47 gpm. 2 inch pipe will easily handle that (and the pump should love it!), and I would see no reason why you could not use a 3/4 hp pump (any pump here in the 3/4 hp range will easily push that). Anything else (unless your flow rates are hugely different) is overkill and will just cost you more to run.

Bruce
 
yes, thats correct. why dont we need to know the head to know what pump we need? is it because the head doesnt change that much from pool to pool, when one knows the pipe size? so, even though the pump is far away etc, the head doesnt go up that much?

EDIT: i guess the proper term is head loss.

EDIT 2: the plan now is to start the pump on saturday, add some chlorine, then do a full set of test. I read about the problem that can happen if one adds CYA before chlorine, so i will add CYA later on. The ph is a bit high, so i will add some muriatic acid on saturday after adding chlorine. Are there any other pitfalls than the cya without chlorine problem? I have no experience with this kind of thing. any tips on handling the muriatic acid in the safest way, for example?

I also recalculated the amount of water in our pool, up from 17000 to 20000 gallons. I think this is more accurate.

I was also wondering what the flow rate on the pump spec sheet really is (it says 34 cubic meter pr hour). I understand this has nothing to do with flow rate as usually discussed here (ref frankthailand's post). so, then my question is, what is this number on the pump?

thanks, from us both!
 
Most pumps (again, here) are rated for roughly 60 feet of head. Most times that is sufficient to cover most applications. Your larger pipe diameters should provide good flow without too much worry (although they are too small for a 3 hp pump, in my opinion!).

We add CYA first here, then chlorine (the next day) and then acid, if needed, the following day. I'm sure different areas and different water conditions could change that, but that is how we do a start up here.

Keep us posted!!!

Bruce
 
Here is the pool today. We are very happy with the shape, design etc. later today stone for the deck is coming, and the sand is to be put under the stone. so, today construction will be finalized, only thing left is connect the pump system to the main electricity, this will be done tomorrow.


[attachment=0:2mtc0z10]DSCN0570.JPG[/attachment:2mtc0z10]
 

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Yes.

Fine for your use now but, in time, will build CYA until your pool is unmanageable.....unless you change the water out when it gets too high or switch to an alternate form of chlorine.

PS - simicrinz is absolutely correct about your pump. 3/4 is enough. The 3hp can also push water too forcefully thru your filter unless your filter is designed for a flow rate that I would estimate well over 120gpm with that pump.
 
Hi,

I think that a 3 hp pump will have almost 10 times more friction losses than a 3/4 hp pump.
With the 3/4 you will turn your water in aprox 6 hr. With the 3 hp pump that centainly will not be done
in 1.5 hrs. Maybe 2.5 hrs, so you will be "pumping to waste" your money. I would install 1 hp maximum. The other point is the filtering quality, if you lower the flow rate, the filter works better.

Congratulation for your pool. :wave:
 
i wonder if there is a way to show the pb the argument concerning the hp of the pump. he says he has made his calculations, so if we show a different calculation, it might work better. we need to show we are considering distance from pool, pipe size, pool size etc.

But the realist in me says that he will not change his mind. So, my challenge will be to make this pool work with a 3 hp pump. if i insist on changing pump, the likely scenario is that he will charge full for the pump and the work. i dont want to do that obviously. When we start using the pump i will make some measurements, and we can decide on the likelihood of different problems.
 

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Besides using industry rules of thumb, it can be tricky to right-size a pump. Even pumps with equivalent horsepower vary in their ability to push water. If you have extremely long pipe runs (50, 60, 100 ft...), a large number of elbows, valves and T's supporting lots of equipment and/or large variations in elevation (say, going up a hill or traversing a ridge or roof line) then this might add so much to Total Dynamic Head that you actually require a large pump for your 20K gallon pool.

I'm not hydraulics-educated (except from my months of research prior to contracting my own pool) but I might suggest some sort of compromise with your builder if there isn't any compelling reason to install this macho 3 horse pump. Tell him/her you want to ensure no more than 1 turnover for every 3 or 4 hours or so, then let him/her come back with a alternative pump. Also, remember that the effective "braking horse power" may be different than the HP rating, so a pump that is rated 1.5 HP with a Service Factor of 1.6 will deliver almost 2.5 total horse power.
 
Hello Charlize
Well first of all trying to make your pool work just to keep your PB happy is going work out very expensive for you, also as said before your pump pushes 34m an hour and your filter is rated 30m an hour so even with headloss your filtering will probably not be very good.
Also you just mentioned you got 50kg trychlor so that tells me he he is no expert. 5 kilos of cya is all you needed

Anyway when you get your first bill you will realize that maybe you should have taken heed of what people here all said, get a smaller pump ,
I have lived here for 20 years and built a few houses and 2 pools with another on the way and the trouble is your pb will not want to lose face so he will not admit that maybe the pump is to big. my predictions are 1 when you get your first bill you will think of cutting your run time but with an swg that will be a problem. 2 your first algae outbreak will never clear up because all the Crud will be blown through the filter when you vacuum. 3 3500 bt a month power bill versus 1000 work that out on the cost of a new pump,

By the way what size is your SWG

Also i have a spare 1.5 hp whisperflow if your interested :-D

happy swims
Frank
 
At this point i will let experience tell me what is good. The pump is already installed. Yes, it would really suck if what you write happens frank. But we cant know for sure this will happen. The pump is far from the pool, and the main drain is on the far side on the deep end, so the pipe length from the main drain to the pump house is actually close to 100 feet. And there are many elbows etc. the height difference is 3m, if you measure from the main drain.

But i am not really trying to say that i wont have problems, i am just saying we will see. the worst that can happen is that i must pay extra power the first month and must buy a new pump. If i get an algae galore, i def think my PB will step up to the plate and help me fix it. He is a responsible guy, not a bad man at all (and an engineer). And in the contract i will pay 10% one week after all is up and running, so i can see how the system runs. he has also built over 50 pools, and i have talked to other owners who dont have problems.

btw, the flow of the filter is 32, not 30. The signature was wrong, i have fixed it now. I will go and look at the specs for the swg now, and get back to you on that.

wish us luck,

char


EDIT: the swg is a hurlcon vx 11T max chlorine is 42 g/h. i will add that to the signature too.
 
Beautiful pool, love the pics!
I googled for some info on your equipment, and found that it looks like you have an http://www.astralpool.com/sites/es/pdb.html Aster filter 00501, No Valve, with 2 1/2” connections, 900 mm (35.43 inch) dia., 31 m3/h (8189.3 gallon/hour) flow rate. As noted in the table you took a picture of, it is designed for a pool volume of 170-240 m3(44,909 -63,401 gallons.) An over sized filter is much better then an under sized one. If your pool is 20,000 gallons (75.71 cubic meters) you can filter all of it in 2.4 hours at max flow rate, but you will get better filtering at a slower velocity.
As Bruce alluded to a 6 hour turn-over goal, you would want to flow 12.61 m3/h (3333.33 gallon/h) to get one turn over in six hours (this is assuming no piping restrictions.)
If your pump is 38779 or 38780 on the chart, they are rated at 34 m3/h. A better pump fit might be 38771 or 38773, which are ¾ and 1 hp, and move 11 and 16 m3/h respectively (all are rated with a 10 m head.)
A much better choice, In My Humble Opinion, would be one of the VICTORIA Dual Speed Pumps, but they do not list performance data for them to be able to pick which one best fits your needs(I'd guess the smallest, 45861.) Two speed pumps are usually more expensive to purchase, but will payback in energy savings after a couple of years.
The picture of your SWG controller looks like an Astralpool APR series Salt chlorinator model 40S,code 41350 with a 40 g/h chlorine output, with a cell that looks just like a Zodiac to me. I would be interested in how well you like it, I'm sure that you will! I'd recommend reading so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html about using borates.
Best Wishes, Good Luck, (and more pictures, please)!!!
 
Here is a close up of the swg:

[attachment=1:1h37r8mc]DSCN0592.JPG[/attachment:1h37r8mc]

The stone arrived yesterday:

[attachment=0:1h37r8mc]DSCN0588.JPG[/attachment:1h37r8mc]

My wife and I are going to Chiangmai next week, so no updates. Next update will be heaven or heck i guess, ;).

Thanks for all the help so far!
 

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Hello Charlize how are you :wave:

That's a good size SWG mine makes 24 gph which works out to 1.6 liters of 12.5 % chlorine in 8 hours, i usually run mine 7 hrs a day [12.30_ 2.00 5.00_10.30] and when we are swimming i also turn it on.

So at least if it does work out that your power bill is a bit high you can shorten your run time, you probably could get away with 5 hours maybe.

By the way did you get a good test kit, i got the TF test kit Which was the best thing i ever did. You might able to get something similar in Chang Mai, down here they were 16000 bt. The TF kit cost me 2000bt but i was lucky because a friend bought it over for me. You can order one but you will have to pay for postage obviously. I also got a complete refill kit, if you get it, get extra cya regent.

Just email Duraliegh link below and he will help you out :goodjob:

http://www.tftestkits.net/index.php

Have a good trip
Frank :cheers:

PS are you sure about the 50 kilos of triclhor you will never need to use all that. 10 kilos will add cya 80 ppm fc 120 salt 99 lower ph 6.7 according to the link below :shock: 7 or 8 kilos just cyanuric acid will do

http://www.poolcalculator.com/
 
We got back today. Everything looks fine. They started the pump yesterday. they have added a lot of trichlor at the deep end. I tried to do the chlorine test in the test kit. When i made the simple test, it turned pink. i guess this means chlorine is over 5. i then tried the FAS/DPD. the solution turned pink as it should, after i put the powder in. But then the solution turned clear when i continued to stir. What does this mean? i didnt add the second solution because it says the solution should be pink after the powder.

I havent done any other tests yet.

When the pump is running the PSI meter goes to 1.

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