Trek details
The trek starts with an altitude of 11,800 ft and the highest point is Surkhail Lake which is at 14,100 ft.
There can be 2 options to do the complete trek.
1- Start for Sangar Lake (this point is well before the location shown in above pics) and cross the mountain on left of Sangar Lake to go down to Fairy Lake and then continue towards the remaining 5 lakes till u reach Surkhail Lake then u can come back from main trek of Sat Sar Mala.
2- Start the trek from the main valley of Sat Sar Mala which has been shown in above pics and reach Fairy Lake then go to left side mountains to go through 5 lakes till u reach Surkhail Lake. Come back to Fairy Lake and cross the mountain on its right to reach Sangar Lake and come down through the Sangar Lake valley.
Time log
We used second option but rain didn't allow us to go to Sangar Lake on our way back so we came down after visiting 6 lakes.
Starting time: 11: 20 a.m. - 0km - 11,800 ft
Fairy Lake: 1:15 p.m. - 3 km - 13,300 ft
2nd Lake: 1:17 p.m. - 3.1 km - 13,500 ft
3rd Lake: 1:57 p.m. - 3.5 km - 13,640 ft
4th Lake: 2: 05 p.m. - 3.7 km - 13,700 ft
5th Lake: 2:45 p.m. - 4.2 km - 13,975 ft
Surkhail Lake: 3: 00 p.m. - 4.6 km - 14,100 ft
Back on road: 4:55 p.m. - 8.6 km - 11,800 ft
The return leg was shorter because we did a circle around the lakes starting from 2nd to Surkhail Lake.
The trek is tough for sure !!!!
Specially, the first part of 3 km which takes 2 hours and altitude changes for around 1,500 ft. Since, there is nothing to see in this part other than valley so it takes some motivation and courage to go through this part.
Once u reach Fairy Lake, things get very exciting 
One after the other ... blue after blue ... lake after lake 
Trek conditions
The first part of 3 km is through the valley in grass and flowers on cattle made treks. Nothing tricky and straight walk except that u r rapidly climbing up and altitude is making it hard to catch breath.
The second part of visiting upper lakes is climbing though small stones and big boulders. Normally they are hidden under snow but since we were there in September so the whole structure was visible.
This part can be tough for struggling group members as it puts lots of stress on knee joints and front part of feet along with breathing issues. I was breathing hard in first part but when i passed second lake, breathing was not the issue anymore but my knee joints were talking a lot 
Same thing happened to me on Ansoo Lake trek as well. It could be acclimatization after some time which helps at higher altitudes.
