How fill MKCircleRenderer with blur color - ios

Question

I have implemented custom implementation of MKCircleRenderer.I need to have a circle with attached color. I can fill it with specific color. But how can add blur effect?
Here is my code:
- (void)fillPath:(CGPathRef)path inContext:(CGContextRef)context_{
if(!distance)
return;
#synchronized (self) {
if(!image){
rect = CGPathGetBoundingBox(path);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextAddPath(context, path);
CGContextSetBlendMode (context, kCGBlendModePlusDarker);
CGContextClip(context);
CGFloat gradientLocations[2] = {0, 1.0f};
UIColor* color = [UIColor colorWithHTMLString:#"#27B255"];
const CGFloat* components = CGColorGetComponents(color.CGColor);
CGFloat gradientColors[8] = {components[0], components[1], components[2], 0.3, components[0], components[1], components[2], 0.3};
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, gradientColors, gradientLocations, 2);
CGColorSpaceRelease(colorSpace);
CGPoint gradientCenter = CGPointMake(CGRectGetMidX(rect), CGRectGetMidY(rect));
CGFloat gradientRadius = MIN(rect.size.width, rect.size.height) / 2;
CGContextDrawRadialGradient(context, gradient, gradientCenter, 0, gradientCenter, gradientRadius, kCGGradientDrawsAfterEndLocation);
CGGradientRelease(gradient);
if(distance.accuracy > 0){
CGFloat k = (CGFloat)(rect.size.width/(2*(distance.distance + distance.accuracy)));
CGFloat radius = (distance.distance - distance.accuracy) * k;
if(radius > 0){
CGContextSetFillColorWithColor(context, [UIColor clearColor].CGColor);
CGContextSetBlendMode(context, kCGBlendModeClear);
CGContextAddArc(context, CGRectGetMidX(rect), CGRectGetMidY(rect), radius, 0, 2 * M_PI, 0);
CGContextDrawPath(context, kCGPathFill);
CGContextSetBlendMode(context, kCGBlendModeNormal);
}
}
image = UIGraphicsGetImageFromCurrentImageContext();
image = [UIImageEffects imageByApplyingBlurToImage:image withRadius:1 tintColor:nil saturationDeltaFactor:1.0 maskImage:nil];
UIGraphicsEndImageContext();
}
}
CGContextDrawImage(context_, rect, image.CGImage);
}
I use UIImageEffects classes from Apple, but no result that I expect. Could you provide any other varian how to do this?