Yellow algae problem with sand in my cartridge filter

[davevanloon]

I have an old concrete pool that appears to have been resurfaced probably 16 years ago. My filter is a Hayward cartridge type. My pool water chemistry is within norms (PH 7.4, chlorine currently high - trying to control current yellow algae situation - not rampant but annoying). My pool surface is quite rough, I am getting a lot of white powder/sand in the filter. Could this be from "delamination" and will the rough surface contribute to the yellow algae situation? Could resurfacing my pool solve the problem?

[Denniswiseman]

You need to Slam (Shock Level and Maintain) with relation to Chlorine / CYA Chart and Recommended Pool Levels

Let's have your numbers (CYA is very important)
FC:
TC:
pH:
TA:
CH:
CYA:

You are using Trichlor so are adding CYA constantly
Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
To reduce your CYA you have to do a partial drain and refill
Continous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well

[Teapot]

My pool surface is quite rough, I am getting a lot of white powder/sand in the filter. Could this be from "delamination" and will the rough surface contribute to the yellow algae situation? Could resurfacing my pool solve the problem?

Could well be delamination, as Dennis said lets see all your numbers, baring in mind delamination can be a slow process with damage started some time ago. With expensive finishes like this you need an expensive test kit to keep it good and not relying on 10 dollar test strips.