HEATER / CHEMICAL ISSUE

[Ccsluke]

I’m new to the forum but not with pools. I have an 18x36 oval, in ground, vinyl liner with sand filter and pump sized correctly. It’s a “chlorine” pool (as if there’s any difference in a “Salt” pool, they both are technically chlorine pools other than salt water VS fresh water. I prefer fresh water).
My question is:(my chemicals are perfect, chlorine, total chlorine,PH, total alkalinity, stabilization, etc.). WHEN I TURN ON MY POOL HEATER ON AND HEAT THE WATER, only a few degrees, the pool starts to turn green. Even though chemicals are perfect and I had just given the pool a weekly SHOCK? Why is this happening and does anyone have any suggestions? I can re-shock and add algaecide and clear it up in a few hours. Maybe I should do that first? Just looking for the technical reason why this is happening so I can better understand what’s going on.

[Denniswiseman]

You say your numbers are perfect, how do you test?, why do you shock weekly?, how do you chlorinate?
Let's have your numbers (CYA is very important) Use a pool store if you don't have a FAS/DPD kit
FC:
TC:
pH:
TA:
CH:
CYA:

[Teapot1]

Sure its algae? Metals can also turn the water green but usually clear and green.
Phosphate levels?
Pump correct size for the filter, maybe that one is for later but we'll see.
We await actual numbers as Dennis has asked