Tds

[dhale1]

Hello,

I use Ben's kit to test for everything but I go to the pool store to test for Total Dissolved Solids. I use HTH Shock n Swim periodically to keep Calcium level around 230. I use regular 6% chlorine bleach for daily chlorination.

Pool Size: 25000
Type: White Plaster
Pool Temp: 63 degrees


Using the PS233 the numbers are:

FC: 5.0
CC: 0
TC:5.0
CYA: 65
TA: 120
CAL: 230


OK, here' s the question. Pool store tells me the TDS is 2100 and that I should consider draining and refilling. Is that necessary? What is an acceptable level of TDS?

Thanks
Dianne

[waterbear]

first question, what is the TDS of your fill water? I would not loose too much sleep over TDS unless you were having some water chemistry problems you can't solve. Then it might be an option to explore. TDS means total dissolved solids and that means EVERYTHING that is dissolved in the water--the calcium and magnesium from the hardness, the sodium and potassium from the softness, the chloride from the use of chlorine, the carbonate and biciarbonate from the alkalinity--in short, every ion that is dissolved in your water whether from the fill, the chemicals you put in, or the reactions that occur in your water.

It seems that some of the chemical manufacturers are blaming TDS for what is essentially a high CYA level problem from using trichlor exclusively (or as a twist on that---a high salt level from NOT using their trichlor exclusivlely and using liquid chlorine!--I've seen it both ways!).Unfortunately many 'pool store guys' just don't have a grasp on what is going on in a pool and everything that they know is what the manufacturers tell them. My pool tests out at over 4000ppm TDS! about 3200ppm of that is the salt for my SWG, abut 150ppm is the calcium that I add, etc. I f you don't have any problems enjoy your swimming. Your numbers look like they are pretty good (what is the pH?). BTW 5 ppm is what many on here recommend as the lowest to run your FC with a CYA above 60. Check out this post:
http://www.poolforum.com/pf2/showthread.php?t=365
Happy swimming!

[dhale1]

Waterbear,

Thanks for the reply. I don't know what the TDS of my fill water is (it's public water though). But I will take it to the pool store next time I go to find out. I will not worry about TDS in the pool though unless I develop a water problem.

The pH is 7.5. I'm also adding bleach later today once I backwash and refill a little. I'm working on removing small amounts of water at a time and refilling to get my CYA between 30-50. It's a cloudy day so as soon as I finish that I'm going to up the bleach some.

Thanks again,
Dianne

[waterbear]

well, the lower your get your CYA by dilution the lower you will get your TDS so don't loose to much sleep over the TDS. You CAN run your pool with your current CYA levels by adjusting the FC and shock levels by the chart that I posted the thread to earlier...Ben's "Best Guess CYA chart" . That way you don't have to drain and dilute. Your decision. Should work fine either way.

[CarlD]

FC: 5.0
CC: 0
TC:5.0
CYA: 65
TA: 120
CAL: 230

And you say a pH of 7.5. Numbers don't get much better than that. I'd try to run FC at 6 or 7 with that much CYA, but that's me.

I think TDS is total BS in real-world conditions. But it sounds impressive (like acid demand). With number like yours, and NO discernable problems, go swim and ignore TDS.