ISD Link vs HydroponicsCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ISD Link
This app allows interaction with various smart devices. It prioritizes user privacy by saving all data locally and not collecting personal information. Bluetooth is required for device scanning and connection.
- Smart device interaction
- Local data saving
- No account registration
- Bluetooth connectivity
- Supports numerous device models
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ISD Link is an APP specially designed for smart device interaction. 1. ISD Link does not have an account registration function, and all data on the device is saved locally and will not be uploaded to remote servers. It promises not to collect user information. 2. During use of ISD Link, Bluetooth needs to be turned on for device scanning and connection. 3.ISD Link supports the following devices: TESTV co-branded model PB25DW, TESTV co-branded model PB40, MAG20, PB70W, PB40, PB50DW, PB10DW, PB25DW, ZIP, Power200 series, EDGE, NP2GO, 608PD, A8Air, A4Air, Air8, C4Air, B80 /B60, K4, X16, K2Air, NP2Air, LP2Air.
HydroponicsCalc
Manage your hydroponic garden with this comprehensive tool. Track reservoir levels, mix nutrients precisely, calculate pH and VPD, and document your grow with a journal and harvest log. Supports both US and metric units.
- Reservoir management dashboard
- Concentrate and EC mixing calculators
- pH and VPD calculators
- Grow journal with photo timeline
- Harvest log and ROI dashboard
- Light schedule tracker
- US & Metric unit support
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HydroponicsCalc is the complete grow-management companion for hydroponic gardeners — from beginners mixing their first concentrate bottles to experienced growers running multiple systems. RESERVOIR MANAGEMENT — FRONT AND CENTRE Your grow systems live on the home screen where you need them. See EC, pH, temperature, volume, and grow stage at a glance. Tap Log to record a reading or journal entry without digging through menus. Get change-due warnings before problems develop. CONCENTRATE MIXER Two modes for every workflow: • Bottle → EC: Enter bottle size and coverage target — get exact gram weights per component, dose rate (mL per gallon), and a live EC estimate. • Target EC → Dose: Enter your desired EC — get the mL-per-gallon dose you need. Supports MasterBlend 4-18-38, Jack's 321, General Hydroponics Flora Series, and more. Save your favourite configurations as reusable recipes. EC CALCULATOR Dial in nutrient strength with confidence. Input dose → see estimated EC. Input target EC → get required dose. An EC reference strip shows typical ranges from seedling to aggressive feeding, accounting for your source water baseline. pH CALCULATOR Enter current pH, target pH, and reservoir volume — get the exact mL of adjuster needed. Supports White Vinegar, Phosphoric Acid (pH Down), Potassium Hydroxide (pH Up), and custom adjusters with calibration mode. VPD CALCULATOR Vapour pressure deficit tracking with colour-coded zone feedback. Input air temperature, relative humidity, and leaf temperature offset — instantly see whether you're in the Too Humid, Seedling, Vegetative, Flowering, or Too Dry zone. GROW JOURNAL WITH PHOTO TIMELINE Document your grows with a date-sorted photo diary. Log observations, deficiencies, feedings, milestones, and harvests — with camera or photo library support. Export a full PDF archive of any journal. HARVEST LOG & ROI DASHBOARD Record wet weight, dry weight, and crop name for every harvest. Track cost-per-gram from your nutrient spend. See yield trends over time. Calculate energy costs from your light wattage and schedule. LIGHT SCHEDULE TRACKER Set your light schedule (18/6, 20/4, 12/12, or custom), log your flip date, and get an estimated harvest date with a countdown. US & METRIC Every calculator works in gallons/°F or litres/°C. One tap to switch — all values update instantly. NO SUBSCRIPTIONS. NO ADS. HydroponicsCalc is a one-time purchase. Everything is included. By HackerHomeLab.com
Screenshots
Verdict
The clearest difference is price: ISD Link at Free against HydroponicsCalc's $1.99. ISD Link also leads on ratings volume (23 vs 1) and device support (4 vs 2). HydroponicsCalc's advantage is rating (5.0 vs 2.1). On ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
ISD Link is free to download; HydroponicsCalc costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
HydroponicsCalc holds the better App Store score, 5.0 against 2.1. That said, the two scores are not equally well evidenced: ISD Link has 23 ratings behind it against 1, so its average is the more settled of the two.
| Parameter | ISD Link | HydroponicsCalc |
|---|---|---|
| Price | Free — better | $1.99 |
| Rating | 2.1 (23 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 21.0% of reviews | — |
| Number of ratings | 23 — better | 1 |
| Update frequency | Every 3 weeks | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPad, iPod, Apple Watch — better | iPhone, iPad |
| Requires iOS | 13.0 — better | 26.5 |
| Further details — not scored | ||
| Size | 61 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | 深圳艾斯特创新科技有限公司 | Douglas Stieber |
Customer experience
ISD Link
HydroponicsCalc
In-app purchases
ISD Link
No in-app purchases
HydroponicsCalc
No in-app purchases









