Help with pool!

[illinipdx]

I am trying to help my mom and dad with their pool in Illinois. It's a vinyl liner in-ground pool, L-shaped, between 30K and 40K gallons (I'm trying to get the exact size, sorry).

It's had some algae, which is now at the bottom of the deep end to be vacuumed. They have a Taylor k-2005 test kit (a few years old), so I was able to have them do some of the tests. They also have a new 4-way test so we were able to verify the chorine and Ph, since the taylor kit is a few years old.

FC: off the chart high, pinkish colored (even half diluted)
Ph: Off the chart low (yellow color)
TA: 20
CYA: >100

The vinyl liner and the white plastic parts all took on a yellow tint over the last few days. They tried to brush it, with no sucess.

My mom is headed out to get a new Taylor K-2006 test kit later today- can't wait for Ben's kit :(

Where should I have her start? I'll be visiting her in a week with my kids, so I'm really trying to get this thing figured out before we get there! Any help is really appreciated!

[Simmons99]

Before we can give you any advice - you will need to get us the actual numbers for FC, TC, TA, CA, etc.

For a CYA of 20- you need to shock the pool to 15ppm - testing 3X a day and raising the chlorine level accordingly.

IF the PH is low - adjust that BEFORE getting the chlorine above 10ppm, as a high chlorine level can interfere with accurate PH test results.

Once you have the test results - post those. You may also want to take a sample to a pool store to test for metals (iron and copper) if you have a staining problem - just don't buy anything they tell you to buy.

[DavidD]

FC: off the chart high, pinkish colored (even half diluted)
Ph: Off the chart low (yellow color)


PH, PH, PH, PH! :eek: Start there. Sounds like they are DANGEROUSLY low. Also have her pick up 4 boxes of Borax. Get those numbers as soon as you can.

Dave

[illinipdx]

Here are the updated test results using the new Taylor K2006 test kit:

Fc: 14.8
CC: 2.2
PH: below lowest level (when we did the Base demand test we needed 95 drops)
CYA: >100 (since 100 is the first mark, we are guessing ~110)
TA: 30-40

What should be addressed first? Increasing PH with sodium carbonate, or Increasing Alkalinity with Sodium Bicarbonate? Won't the Sodium Bicarbonate actually increase both? I used the calculator, and it looks like we should use around 22 pounds of Sodium Bicarbonate for the alkalinity.

Just want to be sure before we start.

Thanks for the help!

[SoCalBoo]

Before you start adjusting your chemistry, figure out if you want a CYA level at 100+. Read up on ben's best guess chart and other posts about CYA levels. the problem with high CYA levels is that it takes higher chlorine levels to both sanitize and shock. while CYA is somewhat of a personal choice, I think you'll be hard pressed to find people with pools on this forum maintaining above 90ppm. You'll probably find a few, but I think you'll find most in the 40-60 range. Others feel free to chime in if you think that estimate is off. SWG can influence the desired level of CYA as well.

If you are going to want to lower your CYA level, only way to do it is a partial drain and refill. Since you will be introducing new water if you do that, might make more sense to do the drain first and then react to the new water chemistry. Might help your ph and alk. Would be a shame to work to get them leveled only to decide to drain and refill, and then have to deal with the new chemistry.

If you want to drain, you can figure out how much by 1) figuring out the size of the pool and 2) using the bleachcalc program found on mswsmith's postings (or use google search on 'bleachcalc') to calculate (go to other calcs).