Leaking filter & cloudy water

[Linda M T]

Oh Please help
Been round your site twice and can't seem to get to where I want to be.
I just need some advice on my pool please.
I live in Spain, have a 10 x 5 outdoor pool with a sand filter, its box standard with nowt flash.
Have had no problems for 4 years, just brought it back after a winter of leaving it be, again, and now I have problems.
The in-line filter is leaking no matter what I do, even with a new seal, even when all the valves are closed, is this a problem with the non-return valve on the sand filter pushing water back through the pump?
the leaking stops when I open the release valve on the top of the filter letting air out
And I can't get the water clear, it is cloudy like milk. The chemicals are in spec, I backwash frequently, its not at all green and I have hoovered three times in 4 days, what I am doing wrong?
I am doing the same as every other year but this year its not getting the pool clean.
I only use chlorine shock to start, the chlorine tablets in the skimmers next, a ph balance either up or down as needed, usually down, and when everything else is ok I use copper sulphate in small amounts to clean and "Blue" the water, it has always worked a treat, but this year I am having no luck.
The pool was half drained over winter, as I do every year, and refilled with clean water before I started cleaning.
I am certainly no expert, but not stupid either, and I need some expert advice please as this has me baffled.
Regards

Linda

[Larry]

Hi Linda and welcome to the Pool Care Forums

Can you clarify the following:

Where is the filter leaking from?
Have you opened the sand filter and checked the sand? There may be clumping or solidification of the sand in the filter. The level of the sand may be low. Generally 4 - 5 years is about the useful life of quartz/ silica sand for pool filters.

The cloudy water is due to a chemical imbalance or filtration problems, or both. Please post your numbers and details for the following as per this post:

Problem:

FC:
TC:
pH:
TA:
CH:
CYA:

Other info:

Having all the information at once will enable us to give you better and more accurate advice

Larry