How can I test for this specific potential leak please.

From my filter basket to the inlet pipe entering my pump room, and then from the outlet pipe until the water re-enters my pool.
Please see attached images:

By the look of the entry part of the skimmer box, it could very well leak there. Common spot as they don't install them correctly in a lot of cases.

You cap off each run of pipes on both ends by gluing in PVC ( We use epoxy as it is easier chip apart and take apart when we are done ) and put schrader valve on one end and a 15 # pressure gage on the other end and then pressurise it with a bicycle pump for 4 or 5 days and see if the pressure remains the same.

 

Also after your fitting are installed on both ends and you have pressurised the pipe take a cup of water and put dish soap in and stir it around then take a paper towel and wet it and wipe it around your glued in fitting looking for tiny bubbles . If you see bubbles go back to #1 and start over

Agree with Bagwain; being's where the water is, it's likely pissing through the mouth of the skimmer where it meets the tile.

 

*Pressure testing: bung skimmer and return nozzles and 'squirt' from (removed) valves - the two blue T'eed are skimmer and vac or drain, the top red one is return.

 

Your pool needs a shock by the by. 

Some of the fittings are for low pressure IE rainwater/ wastewater

On 3/4/2020 at 4:59 AM, daveAustin said:

Agree with Bagwain; being's where the water is, it's likely pissing through the mouth of the skimmer where it meets the tile.

 

*Pressure testing: bung skimmer and return nozzles and 'squirt' from (removed) valves - the two blue T'eed are skimmer and vac or drain, the top red one is return.

 

Your pool needs a shock by the by. 

Yes indeed the major leak was found between the tiles and the skimmer.

Greatly relieved that I found it.

Thanks for everybodies in put.