Its true..0.5 PPM of CC, one can smell it & my ozone result

[SPP]

Hello Guys,

I been waiting for my pool FC level to die down and loosing 1 to 1.5 ppm FC a day and finally I can say that previously without the TF test kit...I been blind...

At 5ppm FC and ZERO CC, I can smell chlorine...nose millimeters away from water
At 3PPM FC and 0.5PPM CC, I can smell chloramine...nose 1" away from water

Today at 1.5PPM FC and ZERO CC, I can't smell anything no matter what. Unless I sweat my hand... put it in water and let it dry by wind..then I can smell "chlorine".

So today I took a party grade bath... ..shampoo and all, remove all sweat and oil from my body, brush my tooth , floss my teeth, Listerine my mouth..scrub here..scrub there and immediately jump in the pool, before any sweat develop.. . Took a leisure 10 minute swim just to check the water clarity, pick up some rust flakes at the deep end that keep falling off my sunshade steel frame.

The water visibility and clarity was just so amazing.... , this is definitely a level better than previous best.
It sort of sparkle...its true. If this pool is 165 feet long Olympic length, with this water I could have seen clearly end to end. My pool is shaded. If it is 100% open air and direct sunlight, I would see more details. Having all white tiles does good for clarity check from surface. Dark blue colored tiles in my friend's pool gives clear water color perception from surface, untill I go in the pool and wear my mask, only then I can check if I am getting his usual minimal 25 meters/82 feet visibility. That is the length of his pool.

I have to admit the recently installed ozone generator does make a difference as far as clarity and "feel" is concerned. I can't prove this scientifically but by being in the water with mask all the time, I know when I do get improved clarity and added "sparkle" to the water.

However I can't say how effective the ozone is in "consuming" chlorine or if it reduces my chlorine consumption.
On 10th August, I shocked the pool to 12PPM FC to clear the 1ppm CC, the day I got the TF test kit. The day I install the ozonator, is also the day i got the TF test kit. So I can't compare previous OTO reading since I realized I can't tell by the OTO yellow color if its is 2ppm or 3ppm. Typically I put 12% bleach a day in quantity for 1PPM increase before I install the ozone. I am at CYA 25PPM.

Since my test on a pail of water somehow showed me that I am reading ozone as CC, I shut down the ozonator untill I can remove CC by super chlorinating.

On 13th Aug 10:00AM, I completed the regeneration of my Zelbrite/Zeolite sand media with 10% salt. Mine is
clinoptitolite type which will catch ammonia. There are 100s types of zeolite for different purposes.
So indirectly I am introducing salt for every ammonia taken off... . Waterbear adviced me to hit 200ppm salt if I want the feel of soft water. I think by 5th regeneration I can get that.

On 14th August 06:45AM I got zero CC and left over of 8PPM FC from the 12PPM shock. I then turn on the ozonator.

On the 15th August I took a dip 5 minutes to test water clarity. It was good, but but not as good as today. FC = 6.5 and CC = 0.2 ( sort of ). This is the day I clean my overflow/balancing tank. There is a lot of black smudge-like stuff on the tiled wall. Oil and whatever gets collected here. Wash entire tank ( its concrete and tiled too ) with soap. Throw water out to drain. Add new city water at 1% of pool water.

On 16th Aug, my wive and kids swam for 2 hours. FC = 7PPM CC = 0
This is when I realized that my water circulation is not that great. I can get 1PPM FC difference by testing different part of the pool. Thank U TF-100 ....

On 17th Aug, 09:30AM. One side of pool with less water flow. FC = 6.5 CC = 0.
The other side of the pool with good water flow. FC = 5.5 CC = 0

On 18th Aug, 08:00AM. Pool side with good waterflow. FC = 5.5 CC = 0

On 19th Aug, 08:05AM. Pool side with good water flow. FC = 4.5 CC = 0

On 20th Aug, 07:45AM. Pool side with good water flow. FC = 3.5 CC = 0

On 21st Aug, 08:30AM. Pool side with good water flow. FC = 3 CC = 0

Today 22 Aug. 08:00AM. Pool side with good water flow. FC = 2.5 CC = 0
I swam 10 minutes today before I do further test.
Today 22 Aug. 14:30PM. Pool side with good water flow. FC = 1.5 CC = 0

Main pump run time since 14th Aug has been reduced to only 13 hours a day and that is 1.1 pool water turn over.
I practically do not use my back up trolley pump since the 14th.

I have read alot on the ozone stuff and I think plumbing plays a very important role for proper operation, aside from how powerful the ozone generator is in terms of gram per hour output against the waterflow GPM at the injected point plus all the "Must Do" for ozone. The longer the ozone bubble stays in water within a plumbing, the more effective it becomes since contact times x concentration of ozone equals kill rate for bacteria/virus. However this is easier said than done. Without a contactor tank, this is close to impossible to be very effective.

I think Dell Ozone and Clearwater has quite a good information on ozone for commercial pools.
Since ozone half life is only 12 minutes at 30* Celsius ( 86 *F ) and longer in cooler water. Those in hotter climates must pay more to get the same result when using ozonator. Sadly I fall in this category. However, ozone killing power is better at 30 *C than at lower temperature.

The way I see it by reading so much on ozone, in a residential pool with small ozone at 2 mg per hour like mine, pool owner must not expect magic out of ozone. Please be aware, some companies will call a 2mg ozonator for a 35K gallon as a decently big residential unit.

To what extend can ozone kill all the baddies thru oxidation and thus help chlorine to do more sanitazion dan less oxidation, giving chlorine longer life in your pool.....its just too expensive and complicated on the supporting equipment required if the performance is expected to be a 5 star rating or kill all baddies. I don't want to go into the details and bored you guys to death.

I think I can summarize this way for ozone.
- The company selling the system must be a real honest professional, honest in terms of explaining the high dollars customers have to spend for the targeted result. If I aim to kill Cyrpto, I will go broke for sure.
- Customers must be willing to accomodate the unique ( & expensive ) technical requirement to have a proper ozonated pool

If one buys an ozonator just because it says this is for a "XXX" gallons pool and believe in that a 100%, I think this is why it is said that ozone is not worth buying from most people's experience. There are so many things that can go wrong on a simple ozone add on in a residential pool. I said wrong..meaning ineffective. The simple analogy is : like buying a 200 gallon aquarium circulation pump for use in a 10,000 gallon pool...well sort of.

If you got the $$, going to built a pool from scratch specific to commercial grade ozone standard, follow the German DIN 19643 standard...let me know how it turns out....

So how about my own ozone generator ?
Well I get to play with it.

 

[Guest]

Waterbear adviced me to hit 200ppm salt if I want the feel of soft water. I think by 5th regeneration I can get that.

That was 2000 ppm!

Your review of ozone units was right on the money, IMHO! Ozone, when done properly, can be useful but it's hardly ever done properly (at least not in residential pools and spas). As you pointed out, one of the big problems is the expense of doing it right. I am very glad you mentioned contact chambers for the ozone. THAT is one of the main requirements, IMHO, but it does add considerably to the cost.

Perhaps one day I will take a trip to your part of the world and see your pool. I think we would have fun playing with it! (I've always wanted to learn to dive!)

 

[SPP]

You wrote 200 ppm Obi-Wan....

"As far as making the water 'feel softer', adding salt to about 200 ppm and adding borates to 50 ppm should make the water feel more 'comfortable' since it brings it closer to the bodies isoelectric point."

Never mind, as long I know its 2,000 now. 2,000 is quite salty, I did a simulation once before considering a salt water generator. I mean I can taste "something" in my tounge at 2,000PPM salt.

You are welcome anytime in my woods WB. I can give you Discovery Scuba try out...

Actually if I want to make my own multi baffles contactor tank, it is possible and must be on a different plumbing....yep it will look as ugly as the hoses from my back up trolley.

I can use a slow flow 25 gallon perminute pump. Custom build a contactor tank of 50-65 gallons. Run a cartridge filter with this ozone set up, since I am pumping water anyway. The ozone exhaust vent that usually goes to a destruction unit and vented to free air, I connect that to an air hose and send it to the pool thru a sand stone aerator. If I can set pressure difference, which is slighly positive for ozonated water by means of some sort of water flow regulator and ozonated air on a lower pressure...maybe I can split the air and water. At the same time if the contactor tank is sort of pressurized, I may get better ozone dilution in water....I think.. .

At slow flow of 25GPM and two minutes contact, in theory.... an honest 4 gram ( 4,000 milligram **EDITED**) per hour ozone generator can do 1 turnover of water for my pool per 24 hours and I will get 0.7 ppm ( 0.7 millligram per liter per minute ) of ozone disinfection value. I must refine the calculation to compensate for ozone solubility, temperature, compressor gas flow and so on. EPA Studies I have, showed at 25*Celcius for a 3-log Gardia kill it only requires Contact Time of 0.5 mg/liter/minute. For water temp of 30*C less CT is required. For killing Cypto I do not have a confimed number yet, some says its 1.6 mg per liter per minute is acceptable, I think this is for 3-log.

Since 1 pool water turnover is not the same as 100% of the pool water being filtered thus being ozonated, free chlorine must still be maintained...I suppose. Maybe I can get away with very low ppm. Any low numbers that produce no chlorine smell for me is good. Maybe 0.5 to 1ppm FC. I am not smelling anything at 1.5PPM FC.

Prozone guys told me that the way the injector/venturi that comes with the unit set up violent mixing of ozone into water but for oxidizing and its life in pool and spa is in order of a few seconds. I can smell the ozone from the bubbles that "burps" out of my pool inlet nozzles. If I can smell it, it means the ozone is still active. I assumed so. Many ozone related studies are for drinking water where there must be residual ozone and based on laminar flow, so I was told its a bit different for what I intend to do.

Anyway, if say the amount of ozone that gass off from my pool is still potent, I must then worry about it as far as its effect to swimmer is concerned. Ozone gaseous half life in air is 3 days at 20 *Celsius, I don't have a 30*C one. At -25*C is 8 days and at 120*C is 1.5 hours...that's it.

British safety standard ( WorksafeBC ) for ozone equipment in a working enviroment stated for gaesous ozone :
I believe the table is the same for US OHSA
- 0.01 ppm as odour treshold.
- At 0.1ppm minor eye, nose & throat irritation
- 0.10 to 0.25 for 2 to 5 hours exposure, headache, cough and some reduction in lung function.
Arc welders also get high intermittent ozone exposure of 9ppm which can lead to pneumonia. Acrc welding will be like ozone unit using corona discharge technology. High voltage arcing produces ozone, like lightning for example.

So I must first buy ozone test units that can read gaseous ozone and another that can read dissolved ozone if I ever want to experiment further.

One way to avoid excessive ozone inhallation by swimmer is that, use a timer connected to a solenoid controlling the off gas in the contactor tank. At pool operational times, vent the surplus gas, when pool closed..all ozone to the pool.
Gee..I am becoming ozone mania...

What do you think Obi-Wan....does the quest make sense in trying to disinfect a pool to possibly a bottled water standard ?
The way I see it, I can do all this for about US$4,000 **EDITED** with local resources, except for the ozone generator and pump which must be imported.

***EDITED, calculation error***

 

[chem geek]

From a sanitation point of view, chlorine alone will give you drinking water standard quality unless you've introduced protozoan cysts into the pool (e.g. Giardia or Cryptosporidium). The problem with pool water is everything else that gets added to it chemically over time including various organics from lotions, etc. You should not use pool water to drink from -- even in an emergency it would be better to drink from a hot water heater though short-term pool water drinking isn't serious.

Ozone is a strong oxidizer, but it doesn't oxidize everything. For example, Cyanuric Acid is in the water and is an organic chemical, but doesn't get rapidly oxidized by ozone. Generally speaking, ozone is more useful in a spa where the bather load is automatically much higher due to the small water volume. Even there, however, sufficient oxidizer (chlorine or non-chlorine shock) can manage spa water and those who have used the Dichlor then bleach method have kept their spas clear well beyond normal times for water replacement.

Ozonators are normally designed to be at concentrations such that they will not persist in the general pool water. Usually, ozonators are under-sized in residential pools and aren't that effective. In your case, however, it sounds like the ozonator is rather powerful so is oxidizing organics faster and that is leading to greater water clarity though people with DE filters (or sand with DE added) and a good chlorine regimen also report outstandingly crystal clear water. The downside with having enough ozone is that it may persist longer which is why you smell ozone.

As for chlorine levels when using an ozonator, the ozone is not in the bulk pool water to any great extent (the excess is mostly bubbling out from the returns) so is not sanitizing the bulk pool water. You definitely need chlorine for that, but you are correct that a low level of chlorine can be used for such sanitation, BUT not algae prevention. Algae takes a higher chlorine level to get killed and any algae that gets stuck to your pool surfaces won't circulate through the ozonator so you are at risk of getting algae if you keep the FC too low. If you really want a low FC (technically, a low FC/CYA ratio since that is what determines how much you smell), you may need to use a supplemental algaecide (PolyQuat 60 or a phosphate remover) to prevent algae growth. Your risk is lower due to killing algae that is free-floating and gets circulated through the ozonator, but just as SWG pools can't get away with much less than an FC that is 5% of the CYA level, your pool probably can't get that much lower either (unless you're lucky and have low algal nutrients in the pool).

Richard

 

[Guest]

You wrote 200 ppm Obi-Wan....

I believe that. I have 'helpers' when I type at the computer...a cat and two dogs that just have to be in on the action so I do make typos! :cat: My other dog can't be bothered with the computer!

 

[SPP]

Thank you Richard.

Ozone is said to be not too effective against algae. It is said it can help "floc" a bit, maybe this is why I can see better clarity. I just like the idea that if I can keep a low chlorine level but have a sanitizing level similiar to say 2.5 or 3 ppm FC. Hoping the ozone can fill that gap. Its not that I don't like chlorine but ozone can kill some things better than chlorine, this is why I invested in one. Having additional oxidizer that can ( & a must for ozone anyway) be generated on site, is also a convenient. Its just an added insurance, even though I need a lab test and controlled test to confirm what additional benefits I am actually getting for overall disinfection quality. I am not looking for a chemical free pool or to drink from it.

The ozone short half life at the said 12 minutes is basically like having no ozone in the pool water, just like what you said, it can't be in the bulk of the pool water. Unless I have a pump that can do 6 minutes per turnover..

However, if my calculation is correct, now I am getting 0.3ppm of ozone oxidizing power at the injector tip with my 50GPM water flow, maybe most concentrated for about 7-10 seconds or so. To what extend this does to the overall pool water sanitizing, I can't say. The additional water clarity alone is worth the investment because I am a maniac for improved water clarity. I see improved water clarity as a personal achievement in pool care. Let's not speak of lab test for bacteria/virus yet...

I am a diver that if I go on a very far away trip, sometimes 7 hours by plane and lugging all those heavy equipment...if I get water that gives me 165+ feet visibility...oh my God, the sensation is awesome. Ask any diver, pristine clear water is just so amazingly beautiful. People pay thousand of dollars to dive far away destination that has superb 150+ feet visibility, its one of the reason to dive, aside from the marine life and all. Sometimes I snorkel fish attracting man made bamboo structure anchored at 3,000 feet deep and the visibility is so stunning...I go speechless.

Here is why I said it is worth the investment as it is now.

01. I got what I aim for, obvious better clarity. The sanitizing part I can't say without a lab test and a proper test method.

02. This 2 gram per hour ozone unit only cost me about approx US$1,300 landed. I got a very good deal, I think. If it can live up to its advertised 20,000 hours UV lamp life, that means at 12-14 hours per day pump running, I pay 6.5 US cents per hour or US$0.91 a day in equipment life if it total loss everything including the 2 ballasts in 20K hours. Electric bill not added yet. I have not yet measured the watts consumed, I think its like 500 watts at best.

03. If my water clarity stability can be achieved because I have this ozone unit, meaning I can get away without much additional pump running hours under normal bather load, per extra hour I do not need to run my pump I save 1,600 watts/hour. If I am correct, the electricity is like US$0.08 per Kw/hr or something in my place. I must check.
So, per hour that I do not need to run my pump above my 12 to 14 hours usual pump run time per day, I save NET 1,100 watt/hr ( pump less ozone ). If it is US$0.08 per kw/hr, I then save US 8.8 cents per hour. That means my pump should last longer too. My pump I think is like US$600 or so. I honestly can't remember. I will give it 30,000 hrs life span. That is US 2 cents per hour pump life savings.

Normally I will need to run my pump 10 extra hours if I have like 4-5 divers in the pool for 3 hours on a given day. If I don't do that, I will loose that "final" clarity. Often I need to also run my back up trolley pump at the same time if the divers are "dirty" so to speak. If I can get away with running only 5 extra hours on main pump on average, that means I save 10.8 cents x 5 = 54 cents. So my cost of that extra clearity by ozone is only US$0.37 a day. If I get chlorine stability or using less chlorine, that is another bonus.


At the end of the day, even if my chlorine consumption or my pump running time do not decrease, a figure of an additional only US$30 a month maximum to get the clarity I am getting now, its worth it. The pool itself cost me like US$40K to built including its filtration system and so on, so its a bit less than 1% ( US$360 ) a year to get clearer water. I mean..... personally I do think its worth while.

This is what I been doing for improved clarity.
I go from basic sand filter and added cartridge, slight improvement but I can vacuum without getting fine dirt back in pool.
I replaced sand with Zelbrite. 3 micron capability at average 80% filtration efficiency. It does work. Better clarity improvement than a cartridge add on.
I added second pump on trolley with 10 micron cartridge filter, nothing beats fast turnover if you want fast clarity recovery.
I added double 1 micron bag from Slime Bag dowstream of trolley pump cartridge. Yes, improved clarity.
Now the ozone.
Next possible add on other than ozone....I am still thinking, I have a "target" in mind though.

If I can throw another US$90 a month on ozone to get confirmed disinfection level to get rid of cyrpto and gardia per 12-24 hours after accidental introduction, maybe I will do it. If spending that can also give me another level of water clarity...dang, I would like that. I heard bacteria test is US$70 in my city by a reputable lab...not so cheap hah ?

5% of FC/CYA for my 25PPM CYA is 1.25 PPM FC. No wonder I smell nothing at 1.5PPM. .. .
Gee, I thought FC/CYA relation is about the release of the "working part" of the chlorine...so it has something to do with the smell too ? Thanks Richard, this is good info...

I won't be able to get Polyquat 60 in this country. I will Google phospate remover in its industrial name, I may be able to back track from there.

Thank u Gentlemen...

 

[chem geek]

Your electricity is inexpensive. I pay a marginal rate over 30 cents per Kilowatt-Hour. If you want to save on pump electricity costs, look into a 2-speed or variable speed (or variable flow) pump since running it longer at a lower flow rate can save you a LOT. I used to have a 1 HP pump at around 1700 Watts which was 65 GPM when the solar is off while now it's 275 Watts at 26 GPM. When the solar is on, I went from about 1800 Watts at 52 GPM to now 1500 Watts at 48 GPM. I also eliminated by 3/4 HP booster pump for my pool cleaner. Overall, I've cut my pump electricity bill in half.

I wouldn't worry about Giardia and Crypto. They are only introduced by sick persons who shed the cysts in diarrhea. It's true that ozone will help against them (UV is even better in most cases), but would take many turnovers to clear a pool (it takes 4.6 turnovers to have 99% of the water flow through the ozonator). As for other pathogens, chlorine will take care of virtually everything else -- bacteria and viruses. Any bacteria that form biofilms would do so on pool surfaces that the ozone won't touch anyway and the way to prevent that is to never let the chlorine drop so that the bacteria always get killed before they can form biofilms.

The chlorine that is attached to Cyanuric Acid does not outgas (it's not volatile). What you mostly smell is hypochlorous acid (it is a little volatile) and a little bit of chlorine gas (very volatile, but is in very low concentration in the water) and both are based roughly on the FC/CYA ratio (the aqueous chlorine, Cl₂, is based on the hypochlorous acid concentration).

If 25 ppm CYA works for you in protecting chlorine breakdown from sunlight, then having about 1.5 ppm FC would work. The only thing to watch out for is a heavier bather or organic load that could consume the chlorine and make it drop too low. You should be OK preventing algae so long as you don't let the chlorine drop much lower so you shouldn't need the algaecide, but that's up to you -- it's more like insurance.

Richard

 

[SPP]

Hello Richard,

I have been eyeing the two speed pump. However due to a high TDH, it can't work in my pool. I already saw the pump curve graph, at lower speed it will not overcome the overall resistance I have now.

Now with clean filters and improved plumbing on suction side I did recently ( i gain 1 hg less ) I am getting 8hg on suction and 18 psi at discharge, that's 50.5 feet TDH. The slow speed RPM of a 2 speed pump is typically 1,750 RPM USA 60 hz version and if based on Pentair Whisperflo graph, I can only get no better than 30 feet head. In a 50hz spec, for my country the low speed will be like 17% less, therefore even less head capability for me.

If the variable speed model can have its RPM decreased nicely say by 50 RPM increment by user, that is a possibility. However I do not get the real benefit since my TDH is just too high. I know the electrical consumption chart when RPM is reduced...I am tempted.

Part of the overall fault is the piping. My PB used 1.5" all around. I think the last time I calculated, my water flow is being burdened by an extra 4.21 psi or 9.71 feet TDH equivalent just because I am pushing 50 GPM in a 1.5", instead of 2" pipe. This is the loss only at the output of the pump only. I could not find on-line calculator that can calculate the loss at the suction for 1.5" against 2". The Hayward manual already stated clearly 2" pipe as minimum for my 2HP pump. Everytime I think of this, I want to the PB...

If only you know what I did and went thru in the name of 1hg reduction, you will laugh the whole day..

If my OTO reading back then before TF100 arrival was accurate ( I must say this everytime I speak of OTO test kit ), I was constantly maintaining 0.5 to 1 ppm, that is before I enrolled in "Trouble Free School".. . I did have clouding issue, rare but twice it happened in a year. No green algae though but it was a start I suppose. After that I was maintaining 2 to 2.5 PPM TC ( no TF test kit yet ). I am confident now at 1.5PPM FC and with the ozone help, I hope to be algae free. Let me test this until my water cloud again.

My CH is in range and my CSI is decent, perhaps calcium clouding can be ticked off the suspect list. So cloudy at next occassion will be most likely from bather overload or algae in early attack....we shall see.

If my pool get 3-4 divers in them everyday for non stop 5 days in a row, this is when mild clouding usually will occur, as per my log book. The last time this kind of loading happened and at approx 2.5 PPM TC, the pool did not cloud but I could smell "chlorine". TF kit came in time and it was from 1ppm CC actually. So its a learning everyday and I hope I can profile my water with the TF kit much better from now on.

Give me a few months and a few heavy bather load for at least 4 days in a row, I shall report back to you.

Thanks Richard.

Later,
Surya

 

[JasonLion]

I have been eyeing the two speed pump. However due to a high TDH, it can't work in my pool. I already saw the pump curve graph, at lower speed it will not overcome the overall resistance I have now.

The TDH goes down as the pump speed goes down. With a standard two speed pump you get exactly half the flow rate at low speed that you are getting at high speed, regardless of what your TDH starts out at.

Dynamic head is just that "dynamic". The higher the flow rate the higher the TDH. Dynamic head is basically resistance to flow caused by friction and turbulence, both of which increase at higher flow rates.

 

[SPP]

Dang...I will look up into that again Jason...thanks so much.
Let me locate my old lap top, I have the link to a very easy to use on like pipe calculator.

 

[SPP]

OK, I looked up at Hayward Super 2HP pump chart, and again the classic problem arises. It is based on USA 60hz spec. No mention of RPM, unlike Pentair which is at 3,450 RPM.

I never get the Hayward 50hz pump curve until today. Anyhow i have done test and by measured real time performance, 50hz model being 2 HP ( SF 1.0) is actually almost equivalent in performance to a USA 60hz spec 1.5 HP Super Pump. This is about right.

So now I got 50GPM flow at TDH of 50.5 feet equivalent.
All I got on the two speed curve is also based on USA 60hz, never mind I shall go for that.

So now with standard two speed pump that reduces my flow by 50%, I am looking at 25 GPM flow.
If I cross reference that to a USA 60hz 1.5HP Super Pump, at the low speed 25GPM the max TDH for this pump is 15 feet !!! Wow...how come so low ? The Pentair Whisperflo can do 25+ feet, maybe the SF ratio is higher, I don't know.

Let let me calculate what friction do I get on slower flow.
I know that I am now at 18psi pump discharge side at 50 GPM with clean filters. That is said to equal in 95 feet of straight PVC pipe of 1.5" ID.

Now I reduce the speed to 25GPM and maintained the 95 feet of straight pipe as my resistance value.
Its calculated that the resistance will be only 5 psi.
What I can not figure out is the reduction of suction ( Hg ), I can't find on-line calculator that does that.
I am now at 8hg if clean filter at 50 GPM. Assuming I can use the same reduction ratio 18/5 psi...can I do this ??..for suction, that means I will only get 2.2hg. Ok for fun sake I use 2.2hg.

So 2.2hg x 1.13 and 5 x 2.31 = ( 2.86 + 11.55 ) = 14.41 feet of TDH equivalent.
So even if I use USA spec ( which I can't ), I will get a flow of 5 GPM only...??... I have to re-calculate.

Sorry Jason, my know-how is stuck at this level.
I think the pump will find its own best flow in real operating condition but half the flow of what I get now seems to difficult to achieve.

and if I calculate real heigh of the equipment, this are the numbers :

Water sucked by pump from main drain need to go up by 2 feet if pool is full of water
Water sucked by pump from balancing tank need to go up by 6 feet, this two suction pipes are always parallel in operation.
From pump to sand filter is a climb up of about 9 feet, but what goes up and comes down, its calculated as zero...right ??

Total piping length and multiple elbows an easy 90+ feet with some branching.
Resistance offered by two filters in series...I don't know if at reduced pumping speed.
Resitance offered by the check valve at balancing tank..."X" number.

My hunch and not based on any hydraulics engineering, I think I wiil get no more than 15 GPM based on 60hz pump.
If I use a 50hz motor in real application...I don't know what reduction I will get.

I once run a small 1" pipe for about 1,200 feet on an island. From the well to the pier. So I bought a small pump. There is no elevation on the pipe run, other than the well water need to be lifted up about 7-9 feet to pump impeller and 6 feet of shower head height at the pier. The small pump typical of 25-30 feet head capability will run forever and probably cavitated and never could deliver water to the pier. So I went for a much bigger pump that has higher head capability....that's when the water start flowing decently. I can't remember the flow rate. I wish I knew on-line pipe calculator back then but some contractor I knew laughed at me for using a 1" pipe for such a long run.

If you were to calculate based on all the resistance values I am getting at 50 GPM, what honest GPM do you think I will get if I use a typical 2 speed pump that supposedly will half my flow ?

How accurate is pump affinity law and the Hazzen-Williams equation for pipe calcultor in real world ?

Thanks

 

[JasonLion]

Ah, I forgot, you sometimes have static head in addition to the dynamic head. If you are pumping from the pool back to the pool the lift and drop cancel out and you only have dynamic head. But if you are pumping from the balancing tank then you have 4 feet of static head (lift - drop). Static head remains the same regardless of what speed the pump runs at.

Priming, filling the pipes with water when the pipes start empty, is yet another thing. Normally you would prime at high speed and run at low speed. To fully maintain prime with your setup you would need a check valve in the balancing tank drain line below the balancing tank water level. If I remember correctly you don't have that, so you may always need to startup on high speed when drawing from the balancing tank.

There is some good background material on hydraulics in this article. There is a section in there on pump affinity equations that should answer some of your questions.

When drawing from the pool at low speed, the flow rate really will be half of the high speed flow rate. When drawing from the balancing tank it will be less than that.

 

[SPP]

Gracias Sir

Indeed, I think I have lost my head...