Painting vs Re-Plastering
- Thread starter JPMorgan
- Start date
The meter I am considering purchasing says it can measure Salinity/pH/TDS/EC and temperature. Wouldn't the meter alone be sufficient?
The K-1766 measures only chloride and bromide ions.
The digital meter measures all ions in solution, so this can help assess how much of the TDS is "Salt" and how much is something other than salt.
Because the tests measure salt in different ways, we can see if they get the same number or significantly different numbers.
If the numbers are significantly different, then that points to a lot of TDS that is not salt.
Received the digital water meter today and did an initial test of the water with these readings:
The K-1766 test kit arrives on Thursday and I will post results from that test (and re-test water with the digital meter) at that time.
- uS/cm (electrical conductivity?) - 3100
- ppm (TDS?) - 1550
- salt ppm - 1570
- salt % - .15%
The K-1766 test kit arrives on Thursday and I will post results from that test (and re-test water with the digital meter) at that time.
Did a Google search and came up with this info on an EC of 3100 microsiemens per centimeter (first reading above):
EC is a measure of a substance's ability to carry an electrical current, and it's a good indicator of water quality. The higher the EC, the more impurities, such as dissolved salts, chemicals, and minerals, are in the water.
Here are some typical EC ranges for different types of water:
EC is a measure of a substance's ability to carry an electrical current, and it's a good indicator of water quality. The higher the EC, the more impurities, such as dissolved salts, chemicals, and minerals, are in the water.
Here are some typical EC ranges for different types of water:
- Pure water: 0–200 µS/cm
- Drinking water: 200–800 µS/cm
- Mineral water: 500–1500 µS/cm
- Freshwater pool: 200–800 µS/cm
- Saltwater pool: 3000–6000 µS/cm
- Seawater: 35000–50000 µS/cm
3100 uS/cm converts to about 1,600 ppm salt.
Can you post all chemistry readings?
Can you post the chemistry for the fill water?
Can you list all chemicals used since the pool was filled?
Do you have an estimate of how much evaporation you get?
TDS is not a valid test for pools.
Do not use the TDS setting.
442 Natural Water™ Standard Solution is used in calibrating many Myron L® Instruments. It is the best choice when measuring boiler and cooling water samples, city water supply, lakes, wells, etc. “442” refers to the combination of salts mixed with deionized water to comprise this standard: 40% sodium sulfate, 40% sodium bicarbonate, 20% sodium chloride.
Standard Solutions & Buffers
Ensure specified water testing instrument accuracy. See a list of our Standards Solutions and Buffers (custom solutions available).
www.myronl.com
Attachments
Br - 4
pH - 7.5
TA - 70
CH - 550
pH - 7.7
TA - 110
CH - 150
Bromine tablets; Baking soda; muriatic acid; liquid chlorine
Hard to estimate, but I would say it is relatively low since this is an indoor pool. About once per week I add water for about 5-10 minutes.... not exactly sure how many gallons that would be.
Based on the information I found online for EC (above), 3100 microsiemens seems high for a fresh water pool. So what does this tell me that I need to do?
That accounts for some of the conductivity.
All of these add salt.
Most of the conductivity is salt and the level is ok.
The biggest concern is DMH, which is most accurately estimated from the amount of bromine tabs used.
You get about 3 ppm DMH per pound of tabs.
How many total lbs of tabs have been used since the fill?
The K-1766 salt test results can help assess the situation.
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Every 10 pounds added to 20,000 gallons will add 31 ppm of DMH.
50 pounds of tabs will add 156 ppm of DMH.
The tabs are about 52 % DMH by weight.
Every 10 ppm Bromine from tabs provides 4 ppm DMH.
2.0 ounces of bromine tabs added to 20,000 gallons will add 1 ppm of bromine, 0.4 ppm of DMH and 0.25 ppm of bromide.
50 ounces of BCDMH tabs will add 25 ppm of bromine, 10 ppm of DMH and 6.25 ppm of bromide.
50 pounds of tabs will add 156 ppm of DMH.
The tabs are about 52 % DMH by weight.
Every 10 ppm Bromine from tabs provides 4 ppm DMH.
2.0 ounces of bromine tabs added to 20,000 gallons will add 1 ppm of bromine, 0.4 ppm of DMH and 0.25 ppm of bromide.
50 ounces of BCDMH tabs will add 25 ppm of bromine, 10 ppm of DMH and 6.25 ppm of bromide.
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I would begin diluting on a regular basis.
Maybe overfill and backwash longer or do a Longer Rinse after backwash or use Waste to lose some water.
Now that you have a Salinity Reading, you can track progress on dilution.
What is the fill water salinity reading?
I need to keep better track of this going forward. We purchased 50 lb buckets of bromine tabs on 1/18/23, 8/5/23, and 5/14/24. Pool was filled in January, 2024, but it sat empty for about 2 months. So... it looks like we go through about 50 lbs every 7 months. Best guess is 60-70 lbs of bromine tabs since last fill.
So.... that puts us somewhere between 180 -210 ppm DMH based on 3 ppm per pound of bromine tabs in 20,000 gallons of water (actually 21,350). Keeping things simple and accounting for some dilution over a 7 month period, it sounds to me like it would be a good rule of thumb to change the water after using 50 lb's of bromine tabs.... or at least annually (assuming no partial drain and fill during the period). Sound about right?
I would reduce or eliminate the use of bromine tabs.
You could go to SWG with your Salinity.
If you use bromine tabs, I would dilute regularly.
I would try to do a full water exchange maybe every 12 months.
20,000/365 days = 55 gallons per day.
If you want, you can do a full drain and refill after 50 lbs. of tabs as long as it is safe to completely drain and refill.
In my opinion, doing a continuous water exchange is probably a better choice.
Maybe switch to liquid chlorine or SWG.
Is there a reason you do not want to go salt water?
I have never managed a salt water pool, so that is completely new to me. I have also heard that running SWGs with Intellichem Controllers can have some issues. Also, this will require drawings and permits from the State since it is considered a significant modification. We have an active Permit and we could request an extension and submit the required equipment modifications. However, I think I'd be more inclined to go liquid chlorine. Since we already have a liquid feeder installed (for the outdoor pool), the modifications to feed the indoor pool would be relatively simple. I'm trying to decide the best path forward to recommend to the HOA between staying as is (with frequent water replacement), converting to straight liquid chlorine, or sodium bromide/ liquid chlorine combination. Simplicity in managing the pool (while utilizing the Intellichem Controller) and overall operating costs are the primary considerations. When I suggested to the HOA recently that we might need to drain and clean the indoor pool every year, there was some resistance, as that cost alone is about $2,000... $700 for water and $1,200 for the drain and clean by our pool company. The option that would be least expensive overall and give us the longest water life between refills would probably be the most desirable.
The SWG does not need to be controlled by the IntelliChem.
In my opinion, SWG is the way to go.
What I would do is get a T-15 cell and set the Cell Type to T-5 and run at 1600 ppm salt.
Or you could set the cell type to T-9 and run at 2,200 ppm salt.
As far as modifications go, it is relatively simple.
Managing SWG is very simple because all you do is adjust the output to meet the needs.
I do not know why it would require so much paperwork, design, engineering, architecture, permits, drawings etc.
Seems like a bunch of nonsense to me.
In any case, you are the one that has to decide what you feel best about based on your values.
My goal is to try to help you get enough information to make an informed decision.
In my opinion, SWG is the way to go.
What I would do is get a T-15 cell and set the Cell Type to T-5 and run at 1600 ppm salt.
Or you could set the cell type to T-9 and run at 2,200 ppm salt.
As far as modifications go, it is relatively simple.
Managing SWG is very simple because all you do is adjust the output to meet the needs.
I do not know why it would require so much paperwork, design, engineering, architecture, permits, drawings etc.
Seems like a bunch of nonsense to me.
In any case, you are the one that has to decide what you feel best about based on your values.
My goal is to try to help you get enough information to make an informed decision.
If you can dilute continuously, then you should never need to drain and clean.
In my opinion, SWG is the way to go with maybe 30 ppm CYA or maybe add about 5 lb sodium bromide.
If you got any CCs, add UV.
Commercial pools should dilute based on bather load anyway to reduce organics like carbon based molecules that create persistent Disinfection Byproducts.
Yes, I agree, but this is the way it works in Illinois with respect to "public" pools. Anything that is not a 1:1 replacement requires an engineer to do drawings and a permit from the state. We had to do this when we replaced an old DE filter with a sand filter on our indoor pool this year and swapped out a trichlor feeder for a liquid chlorine feeder on our outdoor pool. No equipment can be changed without drawings and permits unless it is just replacing what is already there.
If best practice is to dilute regularly no mater what sanitation method is used, then the path of least resistance is probably to just stick with the current system and start regular dilution. Going back to your formula, if we want to turn the water over completely in one year, then we should drain and replace about 410 gallons each week (21,350 / 52 = 410 gallons). If our flow rate on the pump is 65 gpm, then that means the filter should be backwashed, rinsed, and/or run to waste for 6-7 minutes each week (410 gallons / 65 gpm = 6.3 minutes) So... this might be the best way to go for now, as I think the HOA is going to be reluctant to change things. Doing this also means we don't incur a $2,000 expense each year, but rather absorb the water cost slowly each month ($740 fill water cost / 12 months = $61.66 per month). Then, maybe plan on complete drain and fill every 2-3 years.
So going back to my test.... I am consistently getting CH readings around 550. However, the pool company tests at about 350. So, I took a sample to Leslie's today and they did the AccuBlue spin test and came up with 354. Why would I be getting such a different reading? Since two were close and I'm way off I'm going to consider the 350 reading valid (not 550) for CH in the pool. The only questionable thing is that I get 7.5 on pH (both with manual testing and from the Intellichem probe and Leslie's test came up with 7.9.... that seems way off. They did get 1600 TDS on their test and I got 1550 with the digital probe yesterday.