FC/CYA - New Dolphin Triton PS Automatic Robotic

Chdalm

Member
Jul 13, 2020
17
Conroe,Texas
Hello,
I am new here, and already read a lot of posts, very, very useful. I have one question regarding my pool, I have Plaste pool, 21,000 gallons.
I purchased the TF100 kit and doing the necessary tests. My CYA is over 100 (my last measurement in the pool store was 175), I assume that is around 140 (not sure) my FC is around 8 ppm. TA is 170 (it was 200 2-5 days ago, following the strategy that I saw in the forum and it is going down everyday) my PH is 7.5.
My question is regarding the new purchased robot, in the manual informs that can be left in the pool if the FC is 4 ppm, but looking the FC/CYA table according with my numbers above my minimum FC must be 8.0. Can I still leave it inside the pool and just take it out when swimming? or it is better to drain the pool, not entire, but some part 10,000 gallon at least?
Thank you
 

Donldson

TFP Expert
LifeTime Supporter
Jun 12, 2009
4,501
NW Ohio
Well, there's two parts to this question:

Do you need to reduce your CYA? Yes. Your CYA is over 100, FC of 8 is for CYA of 100, not "100+". If your guess is correct (I would bet it's higher) then your minimum would be 12 FC. And that's just the minimum, you should be keeping your FC closer to 20. At those levels the pH test doesn't read correctly. So it's just unrealistic to operate a pool at that level, you need to do a significant water change.

Now, do you need to reduce your FC because of the robot? No. The manual is just parroting the old and outdated "over 4 FC is dangerous" myth. It doesn't take CYA in to account. A pool following the FC/CYA Chart will have a much lower active FC level than a pool with no CYA and 4 ppm FC. So the robot will be fine.
 
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Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
841
Verona, MO
To get a rough idea of how much you will need to exchange to lower your CYA:

Mix 10 mL pool water and 20 mL distilled water in a small glass (all measured with graduated syringe) - stir well.
Take 7 mL of the mixed sample and put it in the CYA mixing bottle.
Add 7 mL of CYA test reagent as usual.
Perform test and multiply result by 3 to account for 1 part pool water and 2 parts distilled water used in test.

I wouldn't spend much time balancing TA or anything else until you get your CYA into a workable range. It will all change anyway.
Good Luck on your mission! :)
 
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Chdalm

Member
Jul 13, 2020
17
Conroe,Texas
Thank you so much for support.
I just did not get the part of multiply by 3 the results. What do I have to do with the result? I just would not like to empty totaly the pool. Is that possible? After draining the water can I clean the walls withs chlorine since there are some yellow spots hard to get it out?
I can send some photos tomorrow morning
Thanks again
Carloa
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
841
Verona, MO
Multiply by 3 because the tested sample is diluted with the distilled water. Which should then show as maybe 30 to 50 in the cya tube.
3x50=150 CYA which means you will need to exchange ~80% of your water to get to 30 CYA. About 50% to get down to around 80, which is at least a little more manageable.
 
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Chdalm

Member
Jul 13, 2020
17
Conroe,Texas
I did the test and the result is 60*3 = 180 so I have to drain 83%, is that correct? can I do it in steps, I mean, drain 20% then refill and test, and next month more %, something like this? I just would not wanted to waste too much water at once.
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
841
Verona, MO
Yes, you can do that. It will "waste" more water in the long run and require re-balancing each time, but I have seen several that chose that route.
Each time you dilute, the next exchange requires more water to make the same percent difference in CYA level.

20% exchange still leaves you very high CYA. If you can swing a 50% one time, at least your at a somewhat manageable level.
 
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red-beard

Gold Supporter
May 27, 2019
222
Houston, TX
My CYA was well over 100 in May. I drained almost completely and refilled 24,500 gallons (~100K liters) in 24 hours. I used two submersible pumps for the drain and refilled using my fill valve plus 2 hoses. I dumped in enough chlorine to get to 20 PPM as I filled. Another 24 hours later, the water was clear. I just had to get my CYA back to normal and adjust "everything else" back to the normal ranges. For me, managing the pool with a CYA of 30 works.
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,997
Laughlin, NV
Your pool should have an overflow. Or you need to purchase a sump pump.
You cannot drain water using the existing equipment. You have a cartridge filter so no path to waste.
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,997
Laughlin, NV
It controls the flow from the main drain. But, you have no valves to close off the skimmers.

I doubt there is much flow from the main drain, which is not a big deal.