Moving in the right direction

[tim5055]

A little background...

We purchased a home in November with our fist ever pool. It had not been closed (guess I don't really need to here in SC) and was crystal clear. Not knowing any better I dutifully took water samples to a pool store (one we purchased a hot tub from, so they like me ). All winter the numbers the pool store came up with were "perfect" according to them (other than CYA which according to them was 98). I suspect that the previous owner just dumped all his chemicals into the pool as he was leaving, but I can't prove it.

Just for giggles I went to a second pool store and they also said I was OK, but they came up with 151 for CYA. According to them I was getting close to "chlorine lock".

I decided to take matters into my own hand and began searching and found Ben Powell at his web site The PoolForum. After a lot of reading I decided the BBB Method was for me. I purchased a Taylor K2006 kit and began testing. A little more poking around brought me here.....

My first numbers from my testing at the beginning of April:
FC 6.2
CC 0.0
pH 7.8
Alk 120
CYA 200+ (even diluting the sample it was off the scale)
CH 300

The only thing I have been using is bleach and muratic acid for over a month. I have been quick to back wash and refill the pool with tap water. Today I drained it to the the skimmers and refilled. Now I can see a CYA number (still by diluting).

This afternoons numbers
FC 12
CC 0.0
pH 7.4
Alk 110
CYA 180

I still have to work on getting the CYA below 100, but everything is moving in the right direction. My nly issue will be keeping the FC up when we go away a couple of times this summer. Right now it is working out that I only need to add one gallon of bleach about every 2.5 - 3 days, but we do have a couple of week long trips scheduled.

 

[jblizzle]

Plugging in the CYA of 180ppm into PoolMath, you MINIMUM FC level should be 14ppm if you hope to prevent algae from starting ... which means you should be targeting 16-17ppm everyday to keep it above 14.

One issue with this is that the pH test is not valid when your FC > 10ppm.

What you really need to do is replace about 75% of your water (assuming you do not have high ground water). OR replace 50% twice. You need to get that CYA down.

 

[tim5055]

Plugging in the CYA of 180ppm into PoolMath, you MINIMUM FC level should be 14ppm if you hope to prevent algae from starting ... which means you should be targeting 16-17ppm everyday to keep it above 14.

One issue with this is that the pH test is not valid when your FC > 10ppm.

What you really need to do is replace about 75% of your water (assuming you do not have high ground water). OR replace 50% twice. You need to get that CYA down.

I understand and agree with everything you say. The problem I have is that my lot is the lowest in our neighborhood. In a moderate rain hydrostatic pressure pushes water up through the expansion cracks in our driveway/sidewalks so I am very reticent to drain much at all. Today was the lowest I've taken it, which was just enough to keep water spilling into the skimmers.

I think for me it's going to be a long process trying to undo what the previous owner did to the CYA levels. At this point I'm just happy I can read it rather than guess.....

 

[jblizzle]

Then you should consider getting a small submersible pump and drain out the water from one end of the pool while filling at the other. (with the filter pump off of course to reduce the mixing).

 

[frustratedpoolmom]

I handled a pool last year when I took over the CYA was in the 400 range - hard to say cuz with the dilution method you do lose accuracy. I did a series of partial drains with a submersible pump and refills with fresh water to lower it to 180, then every week I vacuumed to waste to the bottom of the skimmer then refilled. Over the course of the summer we got it down to 90. Managed to prevent any algae outbreak by being diligent with the chlorine levels. You can get it done but it's a tedious process to do it this way...

 

[gtemkin]

What others have suggested for similar situations is to purchase a large piece of plastic sheeting (or tape several smaller pieces together). Lay that on top of the pool and pump to drain from beneath the plastic while filing fresh water to the top of the plastic. Sounds like the ideal way with no water wasted.

 

[jblizzle]

What others have suggested for similar situations is to purchase a large piece of plastic sheeting (or tape several smaller pieces together). Lay that on top of the pool and pump to drain from beneath the plastic while filing fresh water to the top of the plastic. Sounds like the ideal way with no water wasted.

Easier said than done. There have been very few people actually try it and we generally do not recommend it any more. The tarp can be expensive, difficult to keep in place, and dangerous if you fell in.

 

[tim5055]

My march downward with the CYA continues. For the past month I have been aggressive with backwashing and vacuuming to waste as well as a couple of partial drains when it's been dry and the ground not too "wet.

FC 10
CC 0.5
pH 7.6
Alk 70
CH 250
CYA 80

I'm happy to have both my minimum and target FC below 10.

Now I have to start looking at my CH/TA as they are both now at the lower levels and have been slowly decreasing over time.

 

[jblizzle]

CH and TA are fine where they are.