Dolphin taking chemicals out of the pool?

Jul 10, 2013
490
Northern Howell, NJ
I have a Dolphin Robot with the very heavy (thick) bag. They advertise that running this unit is like having a separate DE filter on your pool because this bag allows nothing to get through. I was wondering if you guys think I can actually be removing chemicals from the pool that started out as solids. Specifically, stabilizer. Reason I think this is because my CYA always reads low. And year after year I add the recomended amount.

Most recently I added 12 lbs to my 38k Gallon pool. Prior reading was 15. Post reading was only 45. I think it should have gotten to 60-70 with 12 lbs added.

I will mention that when I do clean the bag, very cloudy water rinses from the bag. Now, I do brush pool often, so I always attributed this to plaster dust in the bag. But now thinking it's taking my stabilizer out of solution and trapping it. Thoughts?

As a side note to the moderators, if you believe this discussion belongs in the chemicals and testing section, please move for me. Thanks.

Mike
 
Can't see that being the case (unless you put the Dolphin in before the CYA was dissolved). Do you have an autofill? If so, I"m wondering if you have a leak, and your autofill keeps the pool topped, and you're losing your CYA with the leaking water. Also, how did you test for the CYA?
 
Once the CYA dissolves it will not be removed from the water by a robot. If by chance you added CYA and some of the granuals did not dissolve and you ran the robot, yes it will remove the CYA from the water. The same is true if you added the CYA straight to the skimmer and you backwash before the CYA dissolves.

I have had problems in the past when I have added so many pounds of CYA and it should have raised it up by so much, but it only raised it by half of what it should have. The CYA that I now get from a small pool store, that they sell in bulk, always raises my CYA by the correct amount.

How old is the plaster? If it is more than a month old, you should not be getting plaster dust and you have other things happening in there. It could be as simple the amount of dirt that gets blown into the water.

Pool store testing for CYA is the most inaccurate test they do, computerized or not.
 
Going on the 6th or 7th season. Plaster is in great shape. A little Calcium scale here and there. Worse in the spa, but nothing that rips your feet apart. I guess it's not really plaster dust at this poiunt, but the bag is always very cloudy when I rinse it. Water in pool looks fantasitic. crystal clear.
 
Nope. The computerized tests from a local pool store will not be as accurate as your own readings from the test kit. The fluctuations in your results tell me that the pool store test results are all over the place. I don't think you are losing your CYA like you believe you are. I could be wrong, but you need to post accurate test results. Last year I purchased CYA which happened to be about 50% strength of what it should have been. I had to add twice as much as I should have. Have you got 2 pool stores in your vicinity where you could test for the following:
FC
CC
TA
PH
CH
CYA
 
I do. I have a specialty one and Leslies. I tend to stay away from leslies as they are just kids doing what I would do at home. What home kit you recomend? I currently have a Taylor kit I think I got s few seasons ago at Leslies. It tests the basics, CL, PH & TA as well as CYA & Calcium. But the Calcium uses so much reagent I don't do it too often. and the CYA to me seems very inacurate. The dot doesn't ever go away till I reach the top, but it's the surface tension at that point that's making me not see the dot (if that makes sense)
 

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IN a 38,000 gallon pool 12 lbs of stabilizer would have only raised the CYA by about 35 and there's no way for them to read 15 ppm CYA accurately and the test is only accurate within 10 ppm IF they do it correctly (which they almost never do) so having a reading of 45 after the addition is completely within reason.

People think that because the test results are printed out on some fancy computer gadget it's accurate. That has been proven here time after time to be just the opposite. They are almost never accurate. And the CYA test is the one they are worse at.
 
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