Need Help with Numbers

[Hszwill]

Hello,
I have had a hard time keeping my chlorine levels up. My husband has doubted me using the BBB method because he sees us adding bleach multiple nights of the week. I know there must be an error on my part though. Basically I add 1.5 gallons of 6% every other night. I have a feeling I should be adding more bleach, but then it doesn't seem like it works out to be a cheaper deal.

Another thing that I have noticed is my CYA levels might be low. I did raise them a week ago to 50 from 25, but when I checked 7 days later it was back down to 25. Are the chlorine and cya levels related? What number would be ideal to maintain?

I have not needed to backwash in a few weeks. I have had to add water about every 3 days because of rapid evaporation though. I never knew I would have to add water so much. I bring it to the mid point on my tile and 3 days later it has dropped to below the bottom of the tile.

I don't really know what numbers to look for in Alkalinity and Calcium either. Should I be using those various calculators? I would love to know some set numbers that I can always aim to keep the water at for each of the categories below .

Here is what I tested:

FC 0
CC 0
TC 0
pH 7.5
ALK 110
CAL 140
CYA 25
TEMP 86

I appreciate you advice and time.

[Rangeball]

Your PH and alk #s look fine. You may need to bring your CAL up since you don't have a vinyl liner pool, but wait for advice here as I have no experience with non vinyl lined pools.

1.5g of 6% bleach in your 34,500 gallon pool gives you only 2.6 ppm of FC. Your target FC should be 2.8 (11.5% of your CYA). It's not clear if you added CYA to get to 50 ppm but the pool hasn't tested there yet, but it can take up to a week for CYA to fully dissolve and register via testing.

2.6 ppm of chlorine every other day is probably why you are showing 0 TC. Chlorine is consumed by many things, not just sun. If I were you, I'd add enough bleach to get to the target FC, then add what is being lost daily every night. More trips to the pool, but more stable FC and less chance of algae taking hold.

Using bleach for chlorine isn't necessarily cheaper than other options, but if you stay ahead of your pool, it is much cheaper as it doesn't have the side affects of other standard options (broadcasting dichlor or trichlor puck feeders) and it will give you a nice sparkling pool and save you from spending a bunch of money and headache to clear an algae bloom.

[AnnaK]

Using bleach for chlorine isn't necessarily cheaper than other options, but if you stay ahead of your pool, it is much cheaper as it doesn't have the side affects of other standard options (broadcasting dichlor or trichlor puck feeders) . . .

What are some of the side effects of dichlor/trichlor? I know they add CYA and acidity. What else do they do that might not be desirable?

Anna

[mbar]

The downside of trichlor and dichlor are that they add cya, and are acidic.

Hszwil, You need to add calcium. In a pebletec pool you need to have your calcium level between 200-400. Alkalinity should be 80-120, ph 7.2-7.6, and cya 30-50, Your chlorine level should be in conjunction with the amount of cya you have. It does seem that you are losing a lot of water. You can put a bucket of water beside the pool and measure if the water in the bucket goes down as fast as the water in the pool. If it doesn't, then you have a leak somewhere. That could be how you lost cya (cya can take up to a week to show up after you add it though)

Here is the "best guess chart" to see where your chlorine should be. You should shock your pool if it gets more than .5 combined chlorine.


Use the info in this chart to help you figure out what levels of chlorine you need to maintain in your pool based on the amount of CYA (cyanuric acid, also called stabilizer) that you have in your pool. (FC = free chlorine)

Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

[Hszwill]

Thank you Marie and Rangeball.

I now realize that I haven't ever truely "shocked" my pool--ever . I will attempt to raise the FC to somewhere between 12-15 ppm this weekend. Once I get to that point, should I always maintain a steady FC range between 2-6 ppm since my cya averages between 25-30 ppm?

It is good to know that at least my pH and alk are in normal ranges. But, how do I double my calcium numbers?

I forgot to mention something I have noticed this entire swim season that leaves me clueless. On the deep end of my pool I have a retaining wall that has carter stone mortered on for decoration. It is basically a mini cliff for the kids to jump off of instead of a diving board. Anyway, the tile on the deep end has white stuff all over it and it doesn't seem to want to be scraped off with my nails or the pool brush. Is it calcium? This white stuff on tile is only on the deep end tile, below the mortered stone wall.

Thanks again,
Shannon