diff --git a/ApiCore-Backend/src/extractions/dto/create-extraction.dto.ts b/ApiCore-Backend/src/extractions/dto/create-extraction.dto.ts
index ada16de..69ab7c1 100644
--- a/ApiCore-Backend/src/extractions/dto/create-extraction.dto.ts
+++ b/ApiCore-Backend/src/extractions/dto/create-extraction.dto.ts
@@ -6,6 +6,8 @@ import {
   IsNumber,
   IsOptional,
   IsString,
+  Max,
+  Min,
 } from 'class-validator';
 
 export class CreateExtractionDto {
@@ -22,6 +24,7 @@ export class CreateExtractionDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   amount?: number;
 
   @ApiPropertyOptional()
@@ -32,6 +35,8 @@ export class CreateExtractionDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
+  @Max(100)
   waterContent?: number;
 
   @ApiPropertyOptional()
diff --git a/ApiCore-Backend/src/feedings/dto/create-feeding.dto.ts b/ApiCore-Backend/src/feedings/dto/create-feeding.dto.ts
index b1e6dd6..9bad53b 100644
--- a/ApiCore-Backend/src/feedings/dto/create-feeding.dto.ts
+++ b/ApiCore-Backend/src/feedings/dto/create-feeding.dto.ts
@@ -5,6 +5,7 @@ import {
   IsNumber,
   IsOptional,
   IsString,
+  Min,
 } from 'class-validator';
 import { FeedType } from '../../../generated/prisma';
 
@@ -28,6 +29,7 @@ export class CreateFeedingDto {
 
   @ApiProperty()
   @IsNumber()
+  @Min(0)
   amount!: number;
 
   @ApiProperty()
diff --git a/ApiCore-Backend/src/harvests/dto/create-harvest.dto.ts b/ApiCore-Backend/src/harvests/dto/create-harvest.dto.ts
index c1f606c..100f3b1 100644
--- a/ApiCore-Backend/src/harvests/dto/create-harvest.dto.ts
+++ b/ApiCore-Backend/src/harvests/dto/create-harvest.dto.ts
@@ -7,6 +7,7 @@ import {
   IsNumber,
   IsOptional,
   IsString,
+  Min,
 } from 'class-validator';
 
 export class CreateHarvestDto {
@@ -32,16 +33,19 @@ export class CreateHarvestDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsInt()
+  @Min(0)
   honeySuperCount?: number;
 
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   grossWeight?: number;
 
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   netWeight?: number;
 
   @ApiPropertyOptional()
diff --git a/ApiCore-Backend/src/honey-batches/dto/create-honey-batch.dto.ts b/ApiCore-Backend/src/honey-batches/dto/create-honey-batch.dto.ts
index c20debd..2a82372 100644
--- a/ApiCore-Backend/src/honey-batches/dto/create-honey-batch.dto.ts
+++ b/ApiCore-Backend/src/honey-batches/dto/create-honey-batch.dto.ts
@@ -1,5 +1,5 @@
 import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
-import { IsNumber, IsOptional, IsString } from 'class-validator';
+import { IsNumber, IsOptional, IsString, Max, Min } from 'class-validator';
 
 export class CreateHoneyBatchDto {
   @ApiPropertyOptional({
@@ -22,11 +22,14 @@ export class CreateHoneyBatchDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   amount?: number;
 
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
+  @Max(100)
   waterContent?: number;
 
   @ApiPropertyOptional()
diff --git a/ApiCore-Backend/src/honey-batches/dto/create-honey-measurement.dto.ts b/ApiCore-Backend/src/honey-batches/dto/create-honey-measurement.dto.ts
index 1622202..1e90c44 100644
--- a/ApiCore-Backend/src/honey-batches/dto/create-honey-measurement.dto.ts
+++ b/ApiCore-Backend/src/honey-batches/dto/create-honey-measurement.dto.ts
@@ -1,9 +1,18 @@
 import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
-import { IsDateString, IsNumber, IsOptional, IsString } from 'class-validator';
+import {
+  IsDateString,
+  IsNumber,
+  IsOptional,
+  IsString,
+  Max,
+  Min,
+} from 'class-validator';
 
 export class CreateHoneyMeasurementDto {
   @ApiProperty()
   @IsNumber()
+  @Min(0)
+  @Max(100)
   waterContent!: number;
 
   @ApiProperty()
diff --git a/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts b/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts
index f64f1ed..654294a 100644
--- a/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts
+++ b/ApiCore-Backend/src/storage/dto/create-stock-item.dto.ts
@@ -1,5 +1,5 @@
 import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
-import { IsEnum, IsNumber, IsOptional, IsString } from 'class-validator';
+import { IsEnum, IsNumber, IsOptional, IsString, Min } from 'class-validator';
 import { StockCategory } from '../../../generated/prisma';
 
 export class CreateStockItemDto {
@@ -18,11 +18,13 @@ export class CreateStockItemDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   quantity?: number;
 
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   minThreshold?: number;
 
   @ApiPropertyOptional()
diff --git a/ApiCore-Backend/src/varroa/dto/create-varroa-measurement.dto.ts b/ApiCore-Backend/src/varroa/dto/create-varroa-measurement.dto.ts
index 571eb39..c83fb3a 100644
--- a/ApiCore-Backend/src/varroa/dto/create-varroa-measurement.dto.ts
+++ b/ApiCore-Backend/src/varroa/dto/create-varroa-measurement.dto.ts
@@ -6,6 +6,7 @@ import {
   IsNumber,
   IsOptional,
   IsString,
+  Min,
 } from 'class-validator';
 import { VarroaMethod } from '../../../generated/prisma';
 
@@ -25,16 +26,19 @@ export class CreateVarroaMeasurementDto {
   @ApiPropertyOptional()
   @IsOptional()
   @IsInt()
+  @Min(0)
   durationMinutes?: number;
 
   @ApiPropertyOptional()
   @IsOptional()
   @IsInt()
+  @Min(0)
   miteCount?: number;
 
   @ApiPropertyOptional()
   @IsOptional()
   @IsNumber()
+  @Min(0)
   calculatedValue?: number;
 
   @ApiPropertyOptional()