RE: In-Ground, DE Filter Pool With Clear Green Water

[Watermom]

Just use the 10mL sample instead of the 25mL one as it will save on your reagents.

[barbjack]

Just added the last two gallons of 10% chlorine and 1/3 box of borax tonight after the sun was off the pool. FC was just about zero before the addition. We added 2 gallons last night too and only got it up to 1.2ppm. This a.m. it was pretty much gone.

The water is clear but still Gatorade green, although a little lighter shade. Still have the spider-web like staining on the sides. Could algae be collecting in fine cracks in the plaster? Could this be mustard algae? I've been reading about it, hope we don't have it. And of course, still have the brown iron stains on the stairs. Except for the two white spots where I placed two halves of a vitamin C tablet.

I'm getting pretty frustrated here. My husband seems to think 1-2 gallons of 10% chlorine a day should be enough and is skeptical that we need more. With a CYA level of 90ppm we should be running 5-10ppm chlorine levels at a minimum for manintenence and it looks like we need at least 20-75 for shock levels I think. I have no idea how many gallons that would be for either level. Do we just keep dumping in gallon after gallon until it regesters 20+ppm? And how many would that be? 5 gallons, 10, 20? I want to have the right amount on hand but what is that amount?
Is there a calulator somewhere or a formula that we could plug in our pool gallons + CYA level+ ppm needed? I'm not that good at math, but if I have a formula and a calculator I could probably figure it out. Or is it just add until it's enough, and hold it there for a few days? I guess I want to know how many gallons to have on hand. I don't want to keep running to the store every other day.
My drop dead date of September 1st is fast approching and I've lost a week just waiting for the test kit.

With our CYA levels at 90ppm we would need to keep our Chlorine levels at least to 5ppm for everyday maintenence let alone shock levels. Is there any other method to reduce CYA other than dilution of the pool water? If we dumped 20% of the water would that bring it down to 70%? That wouold be a more manageable level of chlorine to me.

Anyway I'm getting really frustrated and confused at this point. And I haven't even talked about the metal issues.

[PoolDoc]

Your PF is 3.4. 10% chlorine -- if it's still full strength and if it's boxed bleach, it almost certainly is NOT -- contains 10% x 8.5lbs, or 0.85 lbs of chlorine. Multiply your PF x your available chlorine for 5.8 ppm of chlorine IN YOUR POOL, per gallon. In other words, 2 gallons of pool store bleach will add up to 6 ppm. 2 gallons of Walmart bleach (6%) will add about 3.5 ppm.

The fact that you added 2 gallons, and only reached 1.2 ppm tells me your pool store bleach is probably weaker than Walmart bleach!

Your husband is right -- 1 - 2 gallons should be more than enough per day, IF
+ your pool was algae free (but it's not!)
+ had no other chlorine demand (but it doesn't)
+ the pool bleach was full strength (but, in August, it's not)

=> Algae can collect in cracks. Both mustard and black algae do this. BOTH types are VERY chlorine resistant.

=> Adding chlorine, without adding ENOUGH chlorine to kill them, just leaves you in a Vietnam style conflict with your enemy, in which both sides take huge losses and neither side wins. You've got to make up your mind about whether you're willing to do what it takes to win.

=> There's no 'free' way to clean up your pool. We can help you do it better, and for less than a pool store would, but on a 35,000 gallon pool, you are going to have to spend several hundred dollars to get rid of your algae and clean up your stains.

=> You haven't 'lost' any time waiting for the kit: if we take off and start treating your pool without testing and proper prep you could spend several hundred dollars and accomplish nothing.

=> The "PoolCalculator" (poolcalculator.com) allows people to calcuate exact doses . . . but that's only helpful if you know the other stuff you need to know. For example, The PoolCalculator won't help you figure out that your 10% labeled bleach is currently probably 4%! You'd probably end up thinking the PoolCalculator has a math error.

=> This is extremely difficult water:

FC - 1.2 ppm
CC - 0.2
pH - 7.0
TA - 120 ppm
CH - 875 ppm
CYA - 90 ppm

I don't recall ever seeing a calcium level that high, before.

=> Under the circumstances, what I'd recommend is
+ Realize you can NOT use cal hypo (calcium will turn your pool to milk), or
+ Trichlor or dichlor (will add MORE stabilizer)
+ Which leaves bleach . . . BUT your pool store bleach has 'cooked off' in summer heat;
+ Which leaves you buying dozens of gallons of Walmart bleach!
+ 10 gallons tonight; and 10 gallons tomorrow night + brushing would be a start.
+ You MUST keep your pH low, so you need to read the muriatic acid page (see my signature), and get a couple of gallons at Lowes.
+ Once the algae is under control, you have to lower your calcium, because HEDP won't work properly with that much calcium in your water. That's a major process, too.
+ You need to order polyquat, because that's the only thing you can leave in your water while you are messing with all the other stuff.
+ Once you have controlled the algae (not: eradicated -- that's probably not practical, right now!) and lowered the calcium, THEN you can tackle the stains.
+ The only easier path I can think of, is drain and refill, BUT you need to (a) check on the cost, and (b) make sure it will help by testing your fill water and making sure IT doesn't have super high calcium, AND (c) check to make sure there aren't local restrictions on draining and refilling (you are in California, where such restrictions are common).
+ To make SURE you are testing calcium correctly, please watch the Taylor calcium videos on this page: http://www.poolforum.com/pf2/showthread.php?17157

So . . . it's up to you. What do you choose to do?

[barbjack]

Your PF is 3.4. 10% chlorine -- if it's still full strength and if it's boxed bleach, it almost certainly is NOT -- contains 10% x 8.5lbs, or 0.85 lbs of chlorine. Multiply your PF x your available chlorine for 5.8 ppm of chlorine IN YOUR POOL, per gallon. In other words, 2 gallons of pool store bleach will add up to 6 ppm. 2 gallons of Walmart bleach (6%) will add about 3.5 ppm.

The fact that you added 2 gallons, and only reached 1.2 ppm tells me your pool store bleach is probably weaker than Walmart bleach!

Your husband is right -- 1 - 2 gallons should be more than enough per day, IF
+ your pool was algae free (but it's not!)
+ had no other chlorine demand (but it doesn't)
+ the pool bleach was full strength (but, in August, it's not)

=> Algae can collect in cracks. Both mustard and black algae do this. BOTH types are VERY chlorine resistant.

=> Adding chlorine, without adding ENOUGH chlorine to kill them, just leaves you in a Vietnam style conflict with your enemy, in which both sides take huge losses and neither side wins. You've got to make up your mind about whether you're willing to do what it takes to win.

=> There's no 'free' way to clean up your pool. We can help you do it better, and for less than a pool store would, but on a 35,000 gallon pool, you are going to have to spend several hundred dollars to get rid of your algae and clean up your stains. I don't mind spending the money if we get a clean pool, money to me is not the biggest obstetrical. But my husband is still not getting this. (sigh)

=> You haven't 'lost' any time waiting for the kit: if we take off and start treating your pool without testing and proper prep you could spend several hundred dollars and accomplish nothing. True

=> The "PoolCalculator" (poolcalculator.com) allows people to calcuate exact doses . . . but that's only helpful if you know the other stuff you need to know. For example, The PoolCalculator won't help you figure out that your 10% labeled bleach is currently probably 4%! You'd probably end up thinking the PoolCalculator has a math error.

=> This is extremely difficult water:

FC - 1.2 ppm
CC - 0.2
pH - 7.0
TA - 120 ppm
CH - 875 ppm
CYA - 90 ppm

I don't recall ever seeing a calcium level that high, before.

=> Under the circumstances, what I'd recommend is
+ Realize you can NOT use cal hypo (calcium will turn your pool to milk), or
+ Trichlor or dichlor (will add MORE stabilizer)
+ Which leaves bleach . . . BUT your pool store bleach has 'cooked off' in summer heat;
+ Which leaves you buying dozens of gallons of Walmart bleach!
+ 10 gallons tonight; and 10 gallons tomorrow night + brushing would be a start. He's at Walmart now getting 10 gallons of chlorine. But he keeps insisting on getting the 10% pool chlorine, saying it's cheaper. He agreed that the chlorine he bought before was probably dissipated as he buys it at Home Depot and they keep it in the shade but it is outside. I have to work tomorrow, so Monday I'm going to Walmart and get 10 gallons of plain bleach from the laundry area.
+ You MUST keep your pH low, so you need to read the muriatic acid page (see my signature), and get a couple of gallons at Lowes. pH was 7.0 yesterday, will check again today. We still have about 1/2 gallon of muriatic acid on hand, I can get more.
+ Once the algae is under control, you have to lower your calcium, because HEDP won't work properly with that much calcium in your water. That's a major process, too. Then I guess it not a bad thing that I don't have the HEDP yet.
+ You need to order polyquat, because that's the only thing you can leave in your water while you are messing with all the other stuff. I did add 32oz. of polyquat, so I guess this means I need more.
+ Once you have controlled the algae (not: eradicated -- that's probably not practical, right now!) and lowered the calcium, THEN you can tackle the stains. At this point I am putting stain removal on the back burner.
+ The only easier path I can think of, is drain and refill, BUT you need to (a) check on the cost, and (b) make sure it will help by testing your fill water and making sure IT doesn't have super high calcium, AND (c) check to make sure there aren't local restrictions on draining and refilling (you are in California, where such restrictions are common). Don't think our county has those restrictions, but I'll check.
+ To make SURE you are testing calcium correctly, please watch the Taylor calcium videos on this page: http://www.poolforum.com/pf2/showthread.php?17157

OK I did that test now 3 times, 2 times with the instructions to counteract possible high metal ions interference.
I got regular test; 875ppm
interference test; 750ppm both times.


So . . . it's up to you. What do you choose to do?

Just to check I tested the source water;

FC- 0.5
CC- 0.5
pH- 8.0
TA- 75
CH- 75

So our water is a little hard but not much and it looks like the test is good. Could limestone have been leaching into the pool water for a long time? Could this cause such high calcium? We do need to re-plaster soon, we figured we'd do it next summer. If that's the problem with the calcium levels, maybe we'll just try to get rid of the algae and forget the stains, etc. and re-plaster this fall. sigh

Thanks for all the advice, sorry if I sounded impatient, etc. I know everyone is just trying to help and I do appreciate it. I am trying really hard to convince my husband to give up on the pool chlorine and just get plain bleach. He doesn't see the difference even though he admits the Home Depot chlorine is probably weak this time of the summer. We don't use the pool store.
He's figuring that the Walmart pool chlorine has been inside the air conditioned store so it's gonna be better. But I also noticed that the plastic bottles the pool chlorine is packaged in is much thinner than bleach bottles, so it could leach just from that I think even inside a cool store. So I'll get the plain bleach Monday. Thanks again.

[PoolDoc]

Given your source water, I'd DEFINITELY recommend looking at the cost of a partial drain and refill. You actually don't want to drain ALL the way, since with a concrete pool you actually DO have to do all that "water balancing" stuff we normally tell people to ignore -- you NEED more calcium in the water than your fill water has.

Or not -- it would be easier to remover the stains with the soft water, then adjust the 'balance' later, after the metal is gone.

By the way, lime stone (calcium carbonate from the marble dust in plaster, probably) does NOT dissolve into pool water UNLESS your pH is low, as in below 7.0. Given your fill water I'd guess you either had (a) a period where the pH was way too low, OR (b) used calcium hypochlorite shock or chlorine powder for an extended period.

[PoolDoc]

Just thinking. If budget is not a big problem AND you are not planning to re-plaster next spring (which would fix the stains), THEN you might want to do this:
1. Drain the pool.
2. Do a BLEACH rinse to remove as much algae as possible.
3. Refill with soft water.
4. Superchlorinate -- no stabilizer.
5. Then, transition to stain clean-up.
6. Then set up your pool for normal use, and a good winter shutdown, so you are ready to go next spring.