How to make an Sprite turn red and return to the original color?

Question

I am recreating a game in pygame as a hobby, in this game I have a ship that can take a single shot or keep shooting if you hold the button, but the ship will heat up and gain a red coloring. But I’m having a really hard time finding a way to do that, and I’ve even managed to get the ship to turn red, but what it takes is getting her back to normal.

For this I thought to just take away the opacity only of the red Surface, but no satisfactory results.

Below is part of the class code:

class Player(pygame.sprite.Sprite):
    def __init__(self, screen):
        pygame.sprite.Sprite.__init__(self)

        self.image = pygame.image.load(util.decode_b64_img(ship)).convert_alpha()
        self.image = pygame.transform.scale(self.image, (50, 40))

        self.current_heat = 0
        
        self.red_surf = pygame.Surface(self.rect.size, SRCALPHA)
        self.alpha = 255
        self.red_surf.fill((255, 0, 0, self.alpha))

    def heat_cannon(self, heat_value):
        self.current_heat = min(self.current_heat + heat_value, self.resistance)

        self.red_surf.fill((0, 5, 5, 0))
        self.image.blit(self.red_surf, (0, 0), special_flags=BLEND_RGBA_SUB)

    def cool_down(self):
        self.current_heat = max(self.current_heat - self.cool_down_rate, 0)

        self.alpha = max(self.alpha-5, 0)
        self.red_surf.fill((0, 0, 0, self.alpha))
        self.image.blit(self.red_surf, (0, 0))

The problem is in the method cool_down, that the red_surf should be more transparent and not. In my view, it is because of the blend mode that is in the method heat_cannon.

This is only part of the code, but I’ll leave the link to the repository here: https://github.com/HugoPFe/Project-Asteroids

There would be some way around this blend mode and make Surface transparent?