A public pool is overseen by the health department, I can't just switch from trichlor to anything else. That would require a remodel permit and redoing the entire plumbing to accomodate for the replacement disinfectant, which would require demolishing the hotel tower with over 1000 rooms to build a larger pump room.
UV systems prevent algae growth?
- Thread starter Pcmaker
- Start date
cfherrman
TFP Guide
You already hand fed the pool bleach, can you not do that according to regs? Many people hand feed pools with bleach, including myself.
Every 10 ppm of fc added with triclor, you get 6 ppm of cya. It is unsustainable for all pools(unless you get a lot if rain).
Liquid clorine injection might require a some room for a tank, a swg requires very little room, probably close to the amount and install differences as a uv would need.
Every 10 ppm of fc added with triclor, you get 6 ppm of cya. It is unsustainable for all pools(unless you get a lot if rain).
Liquid clorine injection might require a some room for a tank, a swg requires very little room, probably close to the amount and install differences as a uv would need.
I'll look into salt water. From what I understand, it extracts chlorine from salt. What are the downsides?
For a residential pool I can't think of any, to be honest? I can't only see advantages. Will the health department allow you to use one?
Chlorine purchased over time just about equals the cost of buying the SWG at one time, so unless you're broke now its a wash.
Maddie
- Jul 21, 2013
- 53,437
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Folks here are confusing you with residential pool methods designed for small bather loads versus commercial pools whose water care needs to respond to high bather loads and contamination. We have a few commercial pool experts around but they are not joining in. And people may be reluctant to redesign commercial pool sanitation on an Internet forum.
Whoever decided to mix ORP monitoring with trichlor in your hotel pool made poor design decisions. As stated before high CYA interferes with ORP readings. SWG works best with high CYA. With low CYA you need much more SWG capacity.
You need a knowledgeable professional to design a better sanitation system fir your hotel pool.
The ORP system was installed recently. It hooks up to an electronic valve that opens and closes in relation to the ORP setpoint. It actually works perfectly with our 1.6k gallon jaccuzi.
Before we had it installed, we would just crack open the Rainbow 300-29x and adjust daily. Dial it down when the Chlorine is high, dial it up if it's low. Almost always, the Chlorine would be a lot higher than it should be in the pool. Same with the spa, hence why we decided to have the ORP system installed.
The curious thing is that we didn't have this many problems with the pool turning green before. Could be because the Chlorine was always high. It was always arounf 10ppm or higher FAC.
Before we had it installed, we would just crack open the Rainbow 300-29x and adjust daily. Dial it down when the Chlorine is high, dial it up if it's low. Almost always, the Chlorine would be a lot higher than it should be in the pool. Same with the spa, hence why we decided to have the ORP system installed.
The curious thing is that we didn't have this many problems with the pool turning green before. Could be because the Chlorine was always high. It was always arounf 10ppm or higher FAC.
The original builder was required to put in the pool, and chose the cheapest method to chlorinate it. I look after a commercial spa, and can pretty much tell the FC once I know the TA, for example pH is 7.5 and ORP is 750, if the TA is 80, the FC is going to be high; if the TA is 100 it's going to be pretty much bang on, and if the TA is 120, it's going to be low. The monitor assumes that TA is a constant, and it's anything but, in a 20,000 gallon pool it probably varies a lot less then in a 400 gallon pool, but still.
- Jul 21, 2013
- 53,437
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
What are the CYA levels and CYA variability in the Jacuzzi? Does the Jacuzzi also use trichlor tablets?
Whoever made that decision to add the ORP system did not think through how the CYA in the trichlor will interfere with it's consistent operation.
No could be, definitely is. The chemistry doesn't change. It is all about the CYA/FC ratio. Keep FC high enough and the rising level of CYA is not a problem. Refer to [FC/CYA][/FC/CYA]. I will repeat that this chart is for a low bather load residential pool. A high bather load can need more FC then the high end of the recommended ranges. FC up to the "shock FC" values are safe to swim in.
Your ORP system does not properly adjust itself to the rising level of CYA. You will need to continue to handle the adjustments manually. Either lowering the CYA through draining or raising the settings to allow more FC. The ORP system did not achieve the low manual intervention it was intended to achieve.
Spa uses trichlor also and I drain it once a week as a habit. The CYA goes from under 30 after I drain it to around 70-80 after about a week, the I drain it.
- Jul 21, 2013
- 53,437
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
With a once a week drain of the spa there is no time for algae to take hold late in the week when the CYA/FC ratio gets out of wack.
Drain the pool once a week and you would not have an algae problem either.
So far, my plan is to backwash enough each day, that after a week, an equivalent of the entire pool water volume would have been replaced. If I backash/dump 45 mins every day, it would be equal to draining and filling the pool when it comes to the amount taken out and replaced.
That sounds like the plan you need to follow in order to maintain the FC/CYA ratio with your present equipment. Just keep a closer eye on the FC/CYA ratio from now on.
- Jul 21, 2013
- 53,437
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Actually, that is not the way the math works. You are diluting the water and not draining and starting from zero.
Let's say your CYA is 50. You are draining 1/7 of the water every day. Diluting 50 CYA by 1/7 would lower the CYA by about 4 to 46. During that 24 hour period your trichlor is adding 2-4 ppm of CYA. So draining 1/7 every day may keep you about even in CYA.
It is not the same as if you replaced the water every 7 days and started the water CYA at 0.
If you drain and refill the pool enough to get the CYA down around 20 where ORP systems are designed to work, and then backwash and refill enough water each day to keep the CYA about 20 then your plan can work.
I know it's not as good as fully draining the pool, but it's the second best thing.
With salt water chlorinators, are there any residuals to worry about like CYA? I'm heavily looking into it. If there are no downsides, I'll talk my boss into switching over.
The advantage of a SWG is your pool gets dosed with frequent small chlorine injections which keep the chlorine more steady. No more FC 5ppm at 0800 and 2ppm at noon... You set it up so if the pump is running, so is the SWG. And you monitor it with testing so tweak as needed for more of less FC.
You do run the CYA a bit higher to "protect" the FC.
No residuals at all.
Maddie
You do run the CYA a bit higher to "protect" the FC.
No residuals at all.
Maddie
cfherrman
TFP Guide
A swg only produces clorine when your pump is on, I'm guessing you run your pump a lot so no biggie here.
It is slow to produce clorine, many high use pools have two. Get the biggest ones you can. (40k gallons)
Requires one more thing to balance, 3500 ppm salt. Your pool is around 500 ppm salt and you have to add salt with splash out and backwashing. Recommend to get the Taylor salt test.
Our home pools use the high cya (70-90) method to prolong the life of the cell, in your pool it might not work to get a long life, but a swg cell is cheaper than what you are doing now.
Triclor is acidic and lowers the pH and ta as you use it, switching to swg or bleach requires more closely monitored pH as it will rise. You will use more acid. If you need to know how much more we can figure how much acid was being added with the tabs.
Swg plates can scale up in poorly balenced and maintained pool, and may need a acid wash.
It is slow to produce clorine, many high use pools have two. Get the biggest ones you can. (40k gallons)
Requires one more thing to balance, 3500 ppm salt. Your pool is around 500 ppm salt and you have to add salt with splash out and backwashing. Recommend to get the Taylor salt test.
Our home pools use the high cya (70-90) method to prolong the life of the cell, in your pool it might not work to get a long life, but a swg cell is cheaper than what you are doing now.
Triclor is acidic and lowers the pH and ta as you use it, switching to swg or bleach requires more closely monitored pH as it will rise. You will use more acid. If you need to know how much more we can figure how much acid was being added with the tabs.
Swg plates can scale up in poorly balenced and maintained pool, and may need a acid wash.
Our pump runs 24/7 as it is a heated pool. We also replaster the pool every 5 years, so I'm not so worried about acid washing.
As of now, we use a manual vacuum attached to the skimmer. I'm thinking of getting a robot vacuum that goes around by itself. I'm thinking this will help in keeping the pool from turning green also.
As of now, we use a manual vacuum attached to the skimmer. I'm thinking of getting a robot vacuum that goes around by itself. I'm thinking this will help in keeping the pool from turning green also.
A pool turning green has nothing to do with filtration, it's all chemistry. Maintain the FC/CYA ratio [FC/CYA][/FC/CYA] and no green.
Now, in my pool what I found was that there was kind of a dead spot where circulation was poor. My robot did work well at keeping that area mixed well so there was no drop in FC in the area.
- Jul 21, 2013
- 53,437
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Pentair has SWG cells that can be connected together in a master/slave control for multiple cells in large pools.
You need to decide what you will do with your ORP system and the level of CYA you will maintain with a SWG.
You need more SWG capacity if you run lower CYA then what TFP recommends.
You need to decide what you will do with your ORP system and the level of CYA you will maintain with a SWG.
You need more SWG capacity if you run lower CYA then what TFP recommends.