Water chemistry before closing a mesh-covered fiberglass pool to compensate for rainfall & draining

[ba67]

I'm getting ready to do a soft closing of our mesh-covered fiberglass pool because I'm having a terrible time keeping leaves out of the pool. I plan on running the pump with the cover on for approximately a month until the water temperature gets cold enough to close it. Before I put the cover on, I want to make sure all of the chemicals are in order since it will be difficult to add anything with the cover on before it is professionally winterized later this fall. I just did a water test with my Taylor K2006 test kit and it looks like the calcium, TA, and CYA are all low and PH is high. When I took a water sample to a pool store to confirm my CYA test result, I was told that my phosphates are high, which doesn't surprise me since there are always leaves in the pool. I know that I need to decrease the PH since it is 8.0, but I need to know if I need to increase the calcium, TA, and CYA since I've got a mesh cover that lets water in the pool and have to drain water out 4-5 times over the winter. I also need to know if I need to remove the phosphates that were likely caused by the leaves in the pool. Here are the latest test results from my Taylor K2006 test kit:

FC - 4.0
CC - .5
CYA - approximately 20-30 (pool store says it is 27) -- How high should I raise it to since rainfall will lower it over the winter?
CH - 130 -- Is this high enough for fiberglass or should I raise it to 200-300?
TA - 70 -- Does this need to be increased since I tend to open up to low TA?
PH - 8.0 -- How low should I go since I will be operating the pool with the mesh cover on for a month and rainfall will impact the chemicals?
Phosphates - 260 (according to pool store) -- Do I need to lower the phosphates before putting the cover on?

 

[ajw22]

Increase your FC to half SLAM level or about 6.

Your CYA is fine at 30.

CH of 130 is fine unless your FG manufacturer recommends differently.

TA of 70 is fine. If you rasie your TA it will cause your pH to rise faster.

Lower your pH to 7.4-7.6.

Stay out of Pool Stores and ignore phosphates.

You will need to check your FC and possibly add liquid chlorine until your water temperature gets below 60F.

 

[anthonypool89]

stay out of Pool Stores and ignore phosphates.

Great advice! I also have a mesh cover and over the winter frequently check the pH and adjust as needed. I just pull the cover part way off, pre-dissolve the sodium bicarbonate or sodium bisulfate, then I use my kayak paddle to agitate the water best I can. Works pretty well.