High CYA and shock

[Midnight]

Trying to get water chemistry right. Previous pH problem fixed. Tested a few days ago and had a high CYA. It was over 100, diluted by half & got about 140. Cl was very dark yellow. Figured out the problem (dh & I both trying to fix the problem at the same time), now a high CYA (added stabilizer). Started getting piles of loose green dirt in the crevices of the liner, vacuumed bottom of pool right out to the yard and refilled and added a gallon of 6% bleach. Water was crystal clear the next morning. Piles of green dirt returned, repeat same. (Wasn't home much for 2 days, just wanted to keep it from getting worse). Yesterday drained 1/4 of the water, refilled, added 4 bottles of 8.25% bleach to shock this morning (used the pool calculator for amounts).

CL was bright orange. The test kit is out of CYA regeant and not able to afford the Taylor kit for another week or so.

1. Should I take a sample of water to the pool store to test for CYA and chlorine?

2. Can the pool be swimmable with a high cya for the rest of the season? (Maybe about 4 weeks left.)

3. What level should the chlorine be at to be safe to swim?

[PoolDoc]

1. Should I take a sample of water to the pool store to test for CYA and chlorine?

No. They can't help you.

First they cannot test chlorine at the levels you need; you can only do that with an FAS-DPD test. You can *estimate* levels with OTO, but that's all.

Second, your CYA isn't going to change that much. If it was 140, and you drained & replaced 1/4 of the water, it's now right at 100 ppm.


2. Can the pool be swimmable with a high cya for the rest of the season? (Maybe about 4 weeks left.)

Yes. As I've noted, I've been operating a LARGE (200,000+ gallons) commercial pool with CYA ~100 ppm and chlorine between 10 and 30 ppm, with ZERO problems or complaints. (These levels are 2 point code violations, but the inspector hasn't noticed because he uses test strips! He has noticed the pool looks really good . . . but that's been the case for years.)

However, you MUST run high chlorine levels. Since you have only OTO, you need to dose to orange, and let it fall to DARK yellow, and then re-dose to orange again.

The "Best Guess" page, linked in my signature block, explains all this.


3. What level should the chlorine be at to be safe to swim?

Safe? With CYA = 100 ppm, anything below 100 ppm FC is safe for people. Safe for swimsuits is probably below 40 ppm.

[Midnight]

So dose to orange for dailyuse, when it falls to dark yellow, dose to orange again to keep it at the amount needed for daily use? Sorry to sound dumb, I'm still learning.

Shocked it with 4 gallons of 8.25% bleach and it turns BRIGHT orange, is that right or do I need to add more?

The green dirt in the crevices of the liner, algea? Anything else needed? Figured vacuuming it completely out of the pool might help fight it and slowly diluted the water even more. I haven't found polyquat 60% yet, but have one more pool store to try.

Sorry to bother you with so many questions.

[Midnight]

Oh Ben, I also meant to tell you that the weird film on the water that we originally thought would be copper is completely gone. It disappeard as quickly as it appeared. There was a very fine almost oily appearing residue on the water for a short time, that almost looked like someone had worn a lot of suntan oil in the pool. That disappeared by that evening and it has been totally clear of that since. Maybe something from turning the heater on for the first time? The guy who had the pool before seemed to like to buy everything the pool store and catalogue offered, maybe something residual from last year or aliens. I'm not sure.

[Charlie_R]

There may be a good chance the previous owner used potable water antifreeze in the heater. I've seen that leave an oily looking film on a sink full of water on first use in a camp trailer. It does lose it's pink color over time, so you probable wouldn't have noticed it when you opened the valves for your heater.

[Midnight]

Charlie, it wouldn't surprise me.

I wasn't surprised if it was copper, either, because we have had problems with copper in the water in the past, but drained 3/4 of the water and refilled. Can all the water chemistry being off bind up the copper and it's just going to show up later when the water is balanced maybe? I don't see any other color in the water right now, but maybe it's going to still.

[PoolDoc]

Can all the water chemistry being off bind up the copper and it's just going to show up later when the water is balanced maybe?

Low pH can dissolve metals, which may then reappear as stains when the pH and alkalinity are increased. Adding HEDP prior to 're-balancing' can temporarily keep the metals in the soluble (non-staining, but also non-filtering-out) form. The CuLator bags can remove SLOWLY remove metals from pool water but ONLY when the metals are in the soluble form.

If the metals are not actually removed from the water, they will began to reappear. Depending on a number of factors, metal can reappear as debris collected on the filter -- this is a highly desirable outcome. When HEDP is used, the filter should be run 24/7, so that as the HEDP breaks down and releases the metal, there is an improved chance that it will be caught as particles on the filter.