diff --git a/src/aio.c b/src/aio.c
index f2eb17b..b15e11a 100644
--- a/src/aio.c
+++ b/src/aio.c
@@ -9,6 +9,8 @@ static constexpr uint16_t usb_timeout = 250;
 static constexpr uint8_t buf_size = 32; // needs 32 bc of overflow issue on these aios?
 static constexpr uint8_t max_curve_points = 7;
 
+static uint8_t req[buf_size], resp[buf_size];
+
 static struct aio_params_t params = {
 	.fans = {
 		.setpoint = 43.5f,
@@ -21,18 +23,6 @@ static struct aio_params_t params = {
 		},
 	}};
 
-// posts cmd to the aio, puts n bytes of response inside resp buffer
-#define POST_AND_GET_RESP(cmd, n) \
-	uint8_t req = cmd;        \
-	uint8_t resp[buf_size];   \
-	aio_post(dev, &req, 1, resp, n)
-
-// posts 2 bytes of cmd to aio, puts n bytes of response inside resp buffer
-#define POST_AND_GET_RESP2(cmd1, cmd2, n) \
-	uint8_t req[2] = {cmd1, cmd2};    \
-	uint8_t resp[buf_size];           \
-	aio_post(dev, req, 2, resp, n)
-
 // set the duty of both fans at once
 #define SET_FANS_DUTY(dev, duty)  \
 	const uint8_t d = {duty}; \
@@ -58,7 +48,7 @@ static void aio_usb_release(libusb_device_handle *dev) {
 	libusb_release_interface(dev, 0);
 }
 
-static int aio_post(libusb_device_handle *dev, uint8_t *req, const int req_len, uint8_t *resp, const int resp_len) {
+static int aio_post(libusb_device_handle *dev, const int req_len, const int resp_len) {
 	// applog(LOG_DBG, "writing to aio, %02x", req[0]);
 	int ret = 0;
 	ret += libusb_bulk_transfer(dev, 0x01, req, req_len, nullptr, usb_timeout);
@@ -68,7 +58,8 @@ static int aio_post(libusb_device_handle *dev, uint8_t *req, const int req_len,
 
 static float aio_get_water_temp(libusb_device_handle *dev) {
 	static float last_read = 36.6f; // sane init value so it doenst ramp the fan up
-	POST_AND_GET_RESP(0xa9, 6);
+	req[0] = 0xa9;
+	aio_post(dev, 1, 6);
 	const float temp = (float)resp[3] + (float)resp[4] / 10.0f;
 
 	if (temp > 10.0f && temp < 65.0f) {
@@ -81,18 +72,22 @@ static float aio_get_water_temp(libusb_device_handle *dev) {
 }
 
 static uint16_t aio_get_pump_speed(libusb_device_handle *dev) {
-	POST_AND_GET_RESP(0x31, 5);
+	req[0] = 0x31;
+	aio_post(dev, 1, 5);
 	return (uint16_t)(resp[3] << 8 | resp[4]);
 }
 
 static enum aio_pump_mode_t aio_get_pump_mode(libusb_device_handle *dev) {
-	POST_AND_GET_RESP(0x33, 4);
+	req[0] = 0x33;
+	aio_post(dev, 1, 4);
 	return (enum aio_pump_mode_t)resp[3];
 }
 
 static void aio_get_fan_speed(libusb_device_handle *dev, uint16_t *speeds) {
 	for (uint8_t i = 0; i < 2; i++) {
-		POST_AND_GET_RESP2(0x41, i, 6);
+		req[0] = 0x41;
+		req[1] = i;
+		aio_post(dev, 2, 6);
 		speeds[i] = (uint8_t)(resp[4] << 8 | resp[5]);
 	}
 }
@@ -101,21 +96,21 @@ static void aio_set_fan_duty(libusb_device_handle *dev, const uint8_t *duty) {
 	static uint8_t last_duty = 255;
 	if (duty[0] == last_duty)
 		return;
-	uint8_t req[3] = {0x42, 0, 0};
-	uint8_t resp[buf_size];
+	req[0] = 0x42;
 	for (uint8_t i = 0; i < 2; i++) {
 		req[1] = i;
 		req[2] = MIN(MAX(duty[i], 0), 100);
 		if (params.fans.fan_stop && req[2] <= params.fans.min_duty)
 			req[2] = 0;
-		const int ret = aio_post(dev, req, sizeof(req), resp, buf_size);
+		const int ret = aio_post(dev, sizeof(req), buf_size);
 		if (ret == 0)
 			last_duty = req[2];
 	}
 }
 
 static char *aio_get_firmware_version(libusb_device_handle *dev, char *buf) {
-	POST_AND_GET_RESP(0xaa, buf_size);
+	req[0] = 0xaa;
+	aio_post(dev, 1, buf_size);
 	sprintf(buf, "%d.%d.%d.%d", resp[3], resp[4], resp[5], resp[6]);
 	return buf;
 }
@@ -125,7 +120,9 @@ static void aio_set_pump_mode(libusb_device_handle *dev, const enum aio_pump_mod
 	if (mode == last_mode)
 		return;
 	applog(LOG_DBG, "setting pump to %u", mode);
-	POST_AND_GET_RESP2(0x32, (uint8_t)mode, 6);
+	req[0] = 0x32;
+	req[1] = (uint8_t)mode;
+	aio_post(dev, 2, 6);
 	last_mode = mode;
 }
 
@@ -134,7 +131,7 @@ static void aio_set_color(libusb_device_handle *dev, const enum aio_color_mode_t
 		return;
 
 	constexpr uint8_t modes[] = {0x52, 0x55, 0x55, 0x58};
-	uint8_t req[buf_size], resp[buf_size];
+
 
 	req[0] = 0x56;
 	req[1] = color_count;
@@ -145,7 +142,7 @@ static void aio_set_color(libusb_device_handle *dev, const enum aio_color_mode_t
 		memcpy(&req[5], colors, 3); // copy the same color to the 2nd pos in the table
 		req[1] = 2;
 	}
-	aio_post(dev, req, 2 + req[1] * 3, resp, buf_size);
+	aio_post(dev, 2 + req[1] * 3, buf_size);
 
 	// send speed, skip if fixed color
 	if (mode != AIO_COLOR_FIXED) {
@@ -153,13 +150,13 @@ static void aio_set_color(libusb_device_handle *dev, const enum aio_color_mode_t
 		constexpr uint8_t speed_pulse[] = {0x50, 0x37, 0x1E};
 		req[0] = 0x53;
 		req[1] = mode == AIO_COLOR_SHIFT ? speed_shift[speed] : speed_pulse[speed];
-		aio_post(dev, req, 2, resp, buf_size);
+		aio_post(dev,2,  buf_size);
 	}
 
 	// actually set the aio to desired mode
 	req[0] = modes[mode];
 	req[1] = 0x01;
-	aio_post(dev, req, 2, resp, buf_size);
+	aio_post(dev, 2, buf_size);
 }
 
 static void aio_set_fan_curve(libusb_device_handle *dev, const struct curve_point_t *curve, const uint8_t count) {
@@ -175,7 +172,7 @@ static void aio_set_fan_curve(libusb_device_handle *dev, const struct curve_poin
 	for (int i = 0; i < max_curve_points; i++)
 		padded[i] = (i < count) ? curve[i] : curve[count - 1];
 
-	uint8_t req[16], resp[32];
+	// uint8_t req[16], resp[32];
 	req[0] = 0x40;
 
 	// setup request
@@ -187,7 +184,7 @@ static void aio_set_fan_curve(libusb_device_handle *dev, const struct curve_poin
 	// set curve for both fans
 	for (uint8_t i = 0; i < 2; i++) {
 		req[1] = i;
-		aio_post(dev, req, sizeof(req), resp, sizeof(resp));
+		aio_post(dev, sizeof(req), sizeof(resp));
 	}
 	applog(LOG_INF, "set up AIO fan curve");
 }